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2024-02-01 | The discovery of deepwater oil and gas sources has altered the scenario of world production of oil products, attracting even more attention to nickel superalloys. However, this class of materials can be used in several applications. Furthermore, nickel superalloys are highly dependent on their processing history, and the manner in which superalloys react to machining can directly affect the finished product. This work aims to evaluate the surface integrity of two different materials after cryogenic side-milling in conditions that stimulate severe plastic deformation (SPD) and high heat generation. The results show that the material response to machining depends strongly on the pre-processing route instead of most assumptions. While cryogenic cooling led to significant sub-surface hardness and microstructural changes in wrought Inconel 625 alloy, such changes were not observed for clad Inconel 625. Therefore, in order to achieve significant surface integrity changes, process parameters need to be selected and optimized accordingly. Also, the findings indicate that some new factors established significant affect/change surface integrity: (a) SPD through a high r_β/h ratio; (b) the specific pre-processing thermomechanical history of the workpiece material; and (c) and cryogenic cooling, by changing material properties, reducing temperature and altering cutting phenomena and chip formation. | Inconel 625 sustainable milling surface integrity and the dependence on alloy processing route | 10.1007/s00170-023-12938-1 |
2024-02-01 | Environmental-friendly liquid carbon dioxide (LCO_2) and biodegradable coconut oil–based minimum quantity lubrication (MQL) technique play a significant role in green machining compared to conventionally polluting cutting fluids. In this work, analysis of the drilling performance was made for super duplex stainless steel (SDSS) which finds use in numerous industrial applications in marine, petrochemical, and oil industries. Input parameters chosen were the cutting velocity of 60 m/min, feed rate of 0.03, 0.05, 0.07 mm/rev, and varying environmental conditions such as LCO_2, MQL, and flood coolant. Comparison between output parameters and analysis was made in all the environmental conditions based on cutting temperature (T), surface topography, surface roughness (R_a), tool wear, and chip morphology. The application of LCO_2-based drilling process resulted in the dwindling of the cutting temperature (T), improved surface finish, and better chip breakability in comparison to other drilling conditions. Using a scanning electron microscope (SEM), the LCO_2 condition displays the least amount of flank and crater wear. | Experimental analysis on drilling of super duplex stainless steel 2507 (SDSS 2507) using cryogenic LCO_2 and MQL process | 10.1007/s13399-022-02536-8 |
2024-02-01 | We describe a technique to optimize the dynamic performance of microwave SQUID multiplexer (µMUX)-based systems. These systems proved to be adequate for reading out multiple cryogenic detectors simultaneously. However, the requirement for denser detector arrays to increase the sensitivity of scientific experiments makes its design a challenge. When modifying the readout power, there is a trade-off between decreasing the signal-to-noise ratio (SNR) and boosting the nonlinearities of the active devices. The latter is characterized by the spurious free dynamic range (SFDR) parameter and manifests as an increment in the intermodulation products and harmonics power. We estimate the optimal spectral location of the SQUID signal containing the detector information for different channels. Through the technique, what we refer to as Spectral Engineering , it is possible to minimize the SNR degradation while maximizing the SFDR of the detector signal, thus, overcoming the trade-off. | Spectral Engineering for Optimal Signal Performance in the Microwave SQUID Multiplexer | 10.1007/s10909-024-03049-6 |
2024-02-01 | Fabric composites are widely employed in self-lubricating bearing liners as solid lubrication materials. Although the tribological behaviors of fabric composites have been extensively studied, the cryogenic tribological properties and mechanisms have been scarcely reported and are largely unclear to instruct material design for aerospace and other high-tech applications. Herein, the tribological properties of polytetrafluoroethylene (PTFE)-based hybrid-fabric composites were investigated at cryogenic and ambient temperatures in the form of pin-on-disk friction under heavy loads. The results suggest that the friction coefficients of the hybrid-fabric composites obviously increase with a decrease in wear when the temperature drops from 25 to −150 °C. Moreover, thermoplastic polyetherimide (PEI), as an adhesive for fabric composites, has better cryogenic lubrication performance than thermosetting phenol formaldehyde (PF) resin, which can be attributed to the flexible chemical structure of PEI. The excellent lubrication performance of hybrid-fabric composites is attributed to the transfer film formed by PTFE fibers on the surface of fabrics. | Tribological properties of PTFE-based fabric composites at cryogenic temperature | 10.1007/s40544-023-0746-x |
2024-02-01 | The AnaBHEL experiment aims to detect the analog Hawking radiation emitted by an accelerated relativistic plasma mirror for which the effective event horizon is analogous to that of a black hole, thanks to the equivalence principle. This radiation is composed of a few Hawking photons emitted simultaneously in the infrared band and the ‘partner photons’ in the ultraviolet band. The former is emitted in the opposite direction of the mirror propagation and is redshifted in the laboratory frame. In the AnaBHEL scheme, high-intensity petawatt laser pulses, will be used to produce the relativistic accelerated plasma mirrors from a helium gas jet. Infrared and ultraviolet photons generated by the mirrors will be detected by dedicated superconducting nanowire single-photon detectors (SNSPDs) at very low temperature and by multichannel plates at room temperature, respectively. Details of the setup design are discussed. | Design of the Setup for the AnaBHEL Experiment | 10.1007/s10909-023-03032-7 |
2024-02-01 | The challenging characteristics of Inconel 617 (IN617), such as its modest modulus of elasticity, heightened chemical reactivity, and low thermal conductivity, pose difficulties in employing conventional machining methods for this material. This complexity is further amplified when considering the specific requirements for applications in aerospace. Consequently, electric discharge machining (EDM) emerges as a preferred approach for working with this alloy. However, inherent challenges within EDM, specifically electrode wear rate (EWR) and dimensional overcuts, limit its efficacy. To address these issues, a comprehensive exploration of the potential of powder-based additives in waste cooking oil (WCO) against cryogenically treated brass electrode material has been undertaken. The investigation holds pivotal importance because the careful choice of an optimal dielectric plays a significant role in affecting the heat input to the electrode, thereby influencing the melting/vaporization and tool wear of the electrode. It is essential to highlight that these considerations have not been adequately addressed in the current body of literature. The experimentation employs the Response Surface Methodology (RSM) experimental design. The findings indicate that the shallow cryogenically treated (SCT) brass electrode exhibited exceptional performance, yielding the lowest values for electrode wear rate (EWR) at 1.49 mg/min and dimensional overcuts (OC) at 0.01 mm. These results are notably superior, surpassing the least values obtained with the deep cryogenically treated (DCT) brass electrode, showcasing a 202.68% improvement in EWR and a 2.33% improvement in OC. | A comparative study on the effect of deep and shallow cryogenic electrodes on tool wear rate and overcut with waste bio-oil in electric discharge machining | 10.1007/s00170-023-12860-6 |
2024-02-01 | Increasing demands on component properties are leading to the development of high-performance materials for which conventional production methods are reaching their limits from an economic and ecological point of view. In recent years, two technologies have been developed that show great potential compared to conventional machining processes, particularly in machining high-performance materials such as the titanium alloy Ti-6Al-4V. Ultrasonic-assisted machining leads to reduced cutting forces and increased tool life. Cryogenic minimum quantity lubrication prevents the occurrence of high machining temperatures and allows higher material removal rates without a negative impact on tool life. This paper shows the influence of ultrasonic-assisted milling and grinding processes in combination with cryogenic minimum quantity lubrication on the machinability of the high-strength materials Ti-6Al-4V and Zerodur. The investigation addressed cutting forces, tool wear, and surface roughness. The superposition of the technologies resulted in longer tool life and lower tool wear for both milling and grinding. However, the surface roughness was consistently higher due to the ultrasonic superposition. Nevertheless, machining with ultrasonic vibration-assisted cryogenic minimum quantity lubrication has great potential for difficult-to-machine materials, especially due to the reduction in tool wear. | Experimental investigation of ultrasonic vibration-assisted cryogenic minimum quantity lubrication for milling of Ti-6Al-4V and grinding of Zerodur | 10.1007/s11740-023-01214-6 |
2024-02-01 | An experimental apparatus was custom-designed to scrutinize the evolution of temperature and methane pressure during the freezing process in both soft and hard coal samples. Additionally, a thermal–hydrological–mechanical coupling theoretical model was developed, and temperature and methane pressure evolutions were simulated using COMSOL software. It was observed that methane pressure and temperature within the coal samples underwent two distinct phases during the freezing process: an initial rapid decline followed by a more gradual reduction. An exponential function was found to describe aptly the correlation of methane pressure or temperature in the coal samples with both freezing time and radial direction. Moreover, it was discerned that the thermal conductivity of soft coal is inferior to that of hard coal, and the radial decay coefficient of methane pressure or temperature in both types of coal is inversely proportional to freezing time. Significantly, it was revealed that, in post-freezing treatment, ethane pressure in both soft and hard coal could be reduced to 0.74 MPa. This finding elucidates the potential applicability of cryogenic methods for the theoretical elimination of coal seam outbursts. The results furnish a vital understanding of the physical properties of coal under cryogenic conditions, and they can inform the optimization of cryogenic treatment procedures for industrial applications. | Spatial–Temporal Evolution of Temperature and Gas Pressure in Soft and Hard Coal During Cryogenic Treatment: An Experimental and Theoretical Investigation | 10.1007/s11053-023-10287-0 |
2024-01-26 | The study investigates the impact of cryogenic treatment (CT) on the microstructural characteristics and mechanical properties of chromium–molybdenum–vanadium (CrMoV) steels. The microstructures of CrMoV steels were extensively characterized using optical microscopy, scanning electron microscopy, and X-ray diffraction after they underwent CT in this study. Changes in grain size, phase composition, and precipitate distribution were examined to evaluate the impact of the CT on the steel's microstructure. Hardness, tensile strength, and elongation tests were also used to assess the treated CrMoV steels' mechanical characteristics. The investigation aimed to ascertain whether the steel's overall performance was enhanced by CT and to what extent it affected these important mechanical properties. Lastly, Charpy V-notch impact tests were used to evaluate the treated CrMoV steels' impact behavior. In order to understand how CT affected the steel's capacity to sustain dynamic loading circumstances, the impact toughness and energy absorption capabilities were examined. Recrystallization and restriction of grain growth during annealing reduced the average grain size, and further, grain refinement took place during CT. The CT samples had tiny precipitates generated inside them, according to SEM examination. These precipitates are essential for strengthening the substance and preventing grain development. By encouraging the production of these precipitates, the CT strengthened and further refined the microstructure. Phase changes, such as the introduction of new phases or modifications to the relative phase fractions, were seen in the CT samples. CT also caused phase shifts, such as converting residual austenite to martensite. The hardness, tensile strength, and impact energy values of the cryogenic-treated specimens showed a considerable improvement compared to the untreated samples. | Cryogenic Treatment of Chromium–Molybdenum–Vanadium Steels: Unveiling Microstructural Features and Improved Mechanical Properties | 10.1007/s40033-024-00638-3 |
2024-01-25 | In the context of the ATHENA X-IFU Cryogenic AntiCoincidence detector (CryoAC) development, we have studied the thermalization properties of a 2 × 2 mm SQUID chip. The chip is glued on a front-end PCB and operated on the cold stage of a dilution refrigerator ( T _BASE < 20 mK). We performed thermal conductance measurements by using different materials to glue the SQUID chip on the PCB. These have been repeated in subsequent cryostat runs, to highlight degradation effects due to thermal cycles. Here, we present the results obtained by glues and greases widely used in cryogenic environments, i.e., GE 7031 Varnish Glue, Apiezon N Grease and Rubber Cement. | Thermalization of a SQUID Chip at Cryogenic Temperature: Thermal Conductance Measurement for GE 7031 Varnish Glue, Apiezon N Grease and Rubber Cement Between 20 and 200 mK | 10.1007/s10909-023-03038-1 |
2024-01-19 | An electron-on-helium qubit is a promising physical platform for quantum information technologies. Among all the “blueprints” for the qubit realization, a hybrid Rydberg-spin qubit seems to be a promising one toward quantum computing using electron spins. The main technological challenge on the way to such qubits is a detection of fA range image current induced by a Rydberg transition of a single electron. To address this problem, we aim to use a tank LC-circuit in conjunction with a high-impedance and low power dissipation cryogenic amplifier. Here, we report our progress toward realization of a resonant image current detector with a homemade cryogenic amplifier based on FHX13LG HEMT. We present a detailed characterization of the transistor at room and cryogenic temperatures, as well as details of the amplifier design and performance. At the power dissipation level of amplifier well below 100 μW, the measured voltage and current noise level are $$0.6~{\hbox {nV}}/\sqrt{\textrm{Hz}}$$ 0.6 nV / Hz and below 1.5 fA/ $$\sqrt{\textrm{Hz}}$$ Hz , respectively. Based on the actual image current measurements of the Rydberg transition in a many-electron system on liquid helium, we estimate an SNR = 8 with a measurement bandwidth 1 Hz for the detection of a single-electron transition, providing the noise level at the output is solely determined by the noise of the amplifier. | Cryogenic Resonant Amplifier for Electron-on-Helium Image Charge Readout | 10.1007/s10909-023-03033-6 |
2024-01-18 | In this study, a control concept for the simultaneous adjustment of the workpiece residual stresses and the surface roughness when cryogenic hard turning AISI 52100 is presented. The turning process is comprised by two consecutive cuts in which the process parameters vary, focusing on roughing and finishing; i.e. first a high, then a low depth of cut. On the first cut, the surface residual stress is adjusted via the cutting speed. On the second cut, the surface roughness is minimized by adjusting the feed rate while maintaining high compressive residual stresses. The surface residual stresses are determined by XRD and hole drilling measurements. For the estimation of the residual stresses the passive force is used. Based on these results, a control concept is presented which makes several assumptions that are partly validated by experiments. | Control concept for the regulation of the surface layer properties using consecutive cuts in cryogenic hard turning of AISI 52100 | 10.1007/s11740-023-01259-7 |
2024-01-12 | We have developed a cryogenic characterization platform for ultrafast photodiodes, whose time domain responses are extracted by electro-optic sampling using femtosecond laser pulses in a pump-probe configuration. The excitation of the photodiodes with the pump beam and the electro-optic sampling crystals with the probe beam are realized in a fully fiber-coupled manner. This allows us to use the characterization platform at different temperatures, ranging from cryogenic to room temperature. As an application example, we characterize the time-domain response of commercial p-i-n photodiodes with a nominal bandwidth of 20 GHz and 60 GHz at temperatures of 4 K and 300 K and in a large parameter range of photocurrent and reverse bias. For these photodiodes, we detect frequency components up to approximately 250 GHz, while the theoretical bandwidth of our sampling method exceeds 1 THz. Our measurements demonstrate a significant excitation power and temperature dependence of the photodiodes’ ultrafast time responses, reflecting, most likely, changes in carrier mobilities and electric field screening. Since our system is an ideal tool to characterize and optimize the response of fast photodiodes at cryogenic temperatures, it has a direct impact on applications in superconducting quantum technology such as the enhancement of optical links to superconducting qubits and quantum-accurate waveform generators. | Cryogenic Fiber-coupled Electro-optic Characterization Platform for High-speed Photodiodes | 10.1007/s10762-024-00966-1 |
2024-01-06 | Aluminium alloy 6061-T6 (AA6061-T6) shows a promising potential for cryogenic structural applications. This alloy exhibits remarkable monotonic tensile properties at low temperatures. However, there is a limited number of studies on the cryogenic deformation behaviour. In this study, both monotonic and cyclic loading were conducted, and various microstructure characterisation techniques were performed to understand influence of cryogenic temperatures on microstructure evolution and deformation behaviour of this alloy. At cryogenic temperatures, the aluminium alloy exhibited superior mechanical properties over those at room temperature. Yield stress, UTS and elongation at failure increased by 18%, 33%, and 53% at 77 K compared to those at room temperature. Such increase in mechanical properties was attributed by the stronger resistance to dislocation movement due to the reduced thermal assistance. Work hardening rate also increased as dynamic recovery was suppressed at lower temperatures. As a result, a high density of dislocations was evenly distributed within grain interior and led to a homogeneous deformation. The test temperature appeared to have a significant influence on fatigue performance; maximum stress response increased by 23% at 108 K with respect to those at room temperature. During cyclic loading, a high number of dislocations was generated to accommodate prescribed strain because of the resistance to dislocation movement including the pinning of dislocations by β’’ precipitates which are known to be sheared at room temperature. Thus, the alloy exhibited an enhanced cyclic hardening behaviour without a noticeable cyclic softening phase. Fatigue life improved by 143% at 108 K with respect to that at room temperature as the homogeneous deformation prohibited localised slip activity and delayed formation of slip bands which act as crack initiation sites. Moreover, the initiation and propagation of secondary cracks at 108 K retarded the propagation of main crack to improve fatigue life. Graphical Abstract | Cryogenic Deformation Behaviour of Aluminium Alloy 6061-T6 | 10.1007/s12540-023-01594-5 |
2024-01-06 | We demonstrate that cryogenic rolling can simultaneously achieve ultrahigh strength and significant ductility in 316L steel, thereby overcoming the existing limits of its tensile properties. The cryogenic-rolled 316L steel exhibited a 1.1 GPa yield strength (YS) at 298 K. Typically, deformed materials exhibit strain softening immediately after yielding with poor uniform ductility. However, during tensile straining, the cryogenic-rolled 316L steel underwent significant strain hardening despite being severely deformed, thus demonstrating exceptional uniform ductility. Consequently, the cryogenic-rolled 316L steel showed a significantly superior strength–ductility combination, impossible with typical cold rolling. The significantly increased YS of the cryogenic-rolled 316L steel resulted from the combined effect of the presence of the hard martensite phase and the refined austenite grains formed by high-density deformation bands. The significant strain hardening in the cryogenic-rolled 316L steel was possible because the low density of dislocations in the austenite matrix enabled the generation of substantial back stress when newly formed dislocations accumulated at obstacles such as grain boundaries during tensile deformation. Partial dislocations in the cryogenic-rolled 316L steel also contributed to considerable strain hardening by suppressing cross-slip during tensile deformation at 298 K—a well-known major mechanism that weakens strain hardening by facilitating dynamic recovery in metallic materials. Our findings suggest a new microstructural strategy for developing commercial steels with superior tensile properties. Graphical Abstract | Ultrahigh-Strength and Ductile AISI 316L Steel Processed by Cryogenic Rolling | 10.1007/s12540-023-01596-3 |
2024-01-01 | Aluminum alloy thin components are widely applied as structures in aerospace, aircraft, and electric vehicle. It is very challengeable to overcome the coexistence of wrinkling, splitting, and destroyed microstructure by the cold forming or hot forming processes when the components’ size is larger and thickness is thinner. A phenomenon was found by authors that the ductility and hardening ability can be simultaneously enhanced at cryogenic temperatures, which can be used to develop a novel cryogenic forming process for overcoming those problems. In this paper, the bulging and drawing abilities were studied at cryogenic temperatures, which demonstrates that aluminum alloys also have excellent cryogenic formability at complex stress states. Thus, a novel forming process at ultra-low temperature gradient has been developed, and the related development and prospect were introduced. The world’s first cryogenic forming device was developed with a drawing force of 22 MN and a platform size of 3 m. An integral 2219 aluminum alloy rocket tank dome with a diameter of 2.25 m was directly formed from a blank by the novel process at an ultra-low temperature gradient. The cryogenic forming process has considerable potential for large-sized and thin-walled components made of high-strength aluminum alloys, such as 2219 and 2195 aluminum alloys. | Cryogenic Forming Process and Equipment for Aluminum Alloy Thin Shells | 10.1007/978-3-031-40920-2_34 |
2024-01-01 | To fully deploy power of quantum computing (QC), practical quantum computers require the integration of a large number of qubits, e.g., in the thousands and millions, to overcome the fragility of the quantum states. Those qubits reside in extremely low temperatures (e.g., tens of mK) and demand a high degree of integration, low noise, and low power consumption for the control and read-out electronics. Following decades of technology scaling, classic CMOS has achieved extreme miniaturization with a well-established global eco-system. QC/CMOS integration is thus poised to be one the best solutions for the scalability problem for quantum computing. Although intended for applications operating well above 200K, standard CMOS technologies have been experimentally verified to perform well at cryogenic temperatures (cryo-CMOS). However, many challenges remain to enable deployment of cryo-CMOS and integration of QC/CMOS. In this chapter, we explain and address a few of such challenges, focusing on the background and progress of the device physics research. The background and progress of QC, with particular emphasis on silicon spin quantum dot (QD) and its need for QC/CMOS integration, is first introduced. Two critical aspects of the cryo-CMOS behaviors, namely transport and high-frequency noise, are then highlighted. Finally, the chapter is concluded with a brief overview on the needs and challenges of cryogenic numerical simulation tool. | Cryogenic CMOS for Quantum Computing | 10.1007/978-3-031-42478-6_22 |
2024-01-01 | In manufacturing sector, looking for a balance between environmental and technical efficiency taking into account productivity is mandatory. Some sectors, such as the biomedical manufacturing sector, also needs to consider the cleanness inherent to prosthesis manufacturing processes for avoiding pathogens transfer to the human body, that is, neither chemicals, bacteria, nor uncontrolled metals can be introduced during the surgical intervention. This work here presented stems from the idea of analyzing the cleanness of cryogenic cooling to be applied to medical pieces. For this, several samples were machined using CO2 cryogenic technology and oil emulsions, respectively. In particular, a modified milling tool was used to apply not only efficiently as cutting fluid but also as cleaner fluid. Afterwards, they were analyzed by Scanning Electron Microscope (SEM) with the aim of looking for biological remains. Finally, with the aim of validating the modified tool in which CO2 is introduced axially as internal coolant, its tool life was tested in comparison with a conventional one. The results shown that the use of CO2 as internal coolant significantly improves the cleanness of current machining processes in comparison with the use of oil emulsions and the way in which is injected does not affect to machining performance. | A Cleaner Milling Process Replacing Emulsion Coolant by Cryogenics CO2 | 10.1007/s40684-023-00530-7 |
2024-01-01 | The main objective of this article is description of modeling of a cryogenic tank which is fitted for warehousing Liquefied Natural Gas in the event of earthquake. The tank consists of two other tanks: the inner steel tank and the external reinforced prestressed concrete tank. The model of the tank is made in the FEM program—ADINA. The designed structure is a shell structure where walls of the tank are designed as single layer elements and the bottom of the inner tank is designed as multi-layered element. The emphasis in the article is put on the work of the inner tank and the interaction of the tank with the warehoused liquid. Earthquake is an accidental action that is taken into account during the analysis. In the analysis a New Zealand earthquake signal was taken as an excitation signal. The analysis is executed in the time domain. Stress graphs, pressure graphs, displacements graphs maps of reduced stresses and yield stress graphs are shown in the article. | Modeling of the Cryogenic Tank to Warehouse Liquefied Natural Gas (LNG) in the Event of the Earthquake | 10.1007/978-3-031-44955-0_42 |
2024-01-01 | Laminates with ultra-thin plies is a promising new development for polymeric composite materials expected to provide superior resistance to intralaminar crack propagation. The ply thickness effect on the crack initiation stress that according to some theoretical studies on fiber/matrix debonding does not depend on the ply thickness was investigated. Ultra-thin ply carbon fiber/epoxy cross-ply laminates subjected to tensile loading at room, –50, and –150°C temperatures relevant for cryogenic fuel storage, aeronautical, and aerospace applications were studied. The stochastic nature of the crack initiation stress in the 90°-plies was analyzed using Weibull strength distribution. The results obtained show delayed transverse crack initiation only in the thinnest plies with a clear trend that the scale parameter is much larger. This thickness effect on initiation is different than that for crack propagation which is observable in much larger ply thickness range. Regarding crack propagation, it was found that in most cases even at very high applied strain levels (1.5%) only a few transverse cracks have propagated from the specimen edges to its middle. | Transverse Crack Initiation in Thin-Ply Laminates Subjected to Tensile Loading at Low and Cryogenic Temperatures | 10.1007/s11029-023-10156-0 |
2024-01-01 | Cryopreservation technology is used for the storage of biological substances. The present work shows the effect of cryogenic temperature (230 °K) on graded PDMS scaffold degradation at the different rates of cooling (− 5, − 2 and − 1 °K/min). Different 2D structures of 5 × 5 PDMS scaffolds had been designed by variation of hole distance and hole diameter. Transient analysis of different structures was evaluated for defined rate of cooling by using of fully coupled heat transfer in solid and fluid along with solid mechanics physics. Five different parameters (temperature, stress, displacement gradient, strain tensor and deformation gradient) associated with scaffold degradation were observed in the presence of water at the different region of interest (ROI). The result shows that significant variation had been found in all parameters affecting the scaffold's degradation. | Influence of Cryogenic Temperature on Degradation of Step-Graded Scaffold: A CFD Study | 10.1007/978-981-99-6343-0_4 |
2024-01-01 | This paper investigates the feature attribution in remaining useful life (RUL) prediction model of cryogenic ball bearing. The RUL prediction model is constructed based on artificial neural network (ANN) by using the TensorFlow platform for training the degradation curve of bearing. To train the models, 5 run-to-failure (RTF) data of cryogenic ball bearings were used. The experiment was driven to 3,600rpm with 20kN axial load and 2.5kN radial load for accelerated life test (ALT) of bearing. 6 sensor data (motor input current, bearing outer race torque, test bearing temperature, and support bearing top and bottom temperature) were used in each case. Before training, min-max scaler was used to avoid biased toward a specific range of values. The model has 3 hidden layers with 0.25 dropout for each. Mean absolute percentage error (MAPE) and Root mean square error (RMSE) were used for evaluating the model. By applying SHapley Additive exPlanations (SHAP), it was confirmed that the current is the most attributing feature for the RUL prediction model, then the torque. Temperature also attributes to the model in order of distance away from the test bearing. | Investigation on Feature Attribution for Remaining Useful Life Prediction Model of Cryogenic Ball Bearing | 10.1007/978-3-031-40455-9_25 |
2024-01-01 | This article presents the reliability analysis of a High- k stacked Dual Gate Junction-less MOSFET at Deep Cryogenic Temperatures (as low as 50 Kelvin) in terms of dc, analog and RF stability performance metrics. Furthermore, the dc and analog figure of merits in the presence polarized interface trap charge densities has been analyzed at sub-ambient temperatures. The steep ON–OFF switching and the sub-threshold slope profile shows heavy reliance on temperature variations and confirm that the transistor electrostatics improve at lower temperatures. The study reveals the compatibility of the device to perform at cryogenic temperatures and can be integrated with CMOS technology for quantum computations. | Impact of Deep Cryogenic Temperatures on High-k Stacked Dual Gate Junctionless MOSFET Performance: Analog and RF analysis | 10.1007/s12633-023-02705-y |
2024-01-01 | For some modern steels with a body-centered cubic (bcc) crystal structure, it is observed that both tensile strength and ductility are significantly improved with decreasing temperature, which motivates the exploration of the cryogenic formability and fracture properties of these materials. The temperature-dependent plasticity and fracture phenomena of a modern bainitic steels with the bcc structure have been investigated by performing a comprehensive experimental program and finite element simulations, covering a broad range of loading conditions. Uniaxial tensile tests have been performed at different temperatures along three loading directions. Tensile tests using flat specimens with various geometries, including shear, central hole and notched dog bone, have been performed along the rolling direction at room temperature and –196 ℃. An advanced non-associated constitutive plasticity model is used to describe the temperature-dependent strength and hardening properties of the material. The local critical stress and strain variables extracted from finite element simulations of different fracture tests have been used to calibrate a unified fracture criterion, which considers the stress state dependence. The effects of temperature on the plasticity and stress state dependent fracture behavior of the modern bcc steels have been quantitatively determined. | Temperature-Dependent Plasticity and Fracture Properties of Modern BCC Steels | 10.1007/978-3-031-40920-2_50 |
2024-01-01 | Chip formation is dependent on the machining environment and is a major factor representing machining characteristics. This paper experimentally investigates the influence of cryogenic cooling and minimum quantity lubrication (MQL) on chip formation during titanium milling and their effects on tool wear and cutting force. Chip segmentation, shear angle, grain size, and compositions were evaluated according to the tool wear evolution. An application of cryoMQL strategy, which means the use of cryogenic cooling and MQL simultaneously, delayed the time of chip serration; serrated chips appeared at long machining distances compared to the dry machining. Then, the cryoMQL machining increased the shear angle and decreased grain size and oxygen atomic percentage. The phenomena represented occurrences of effective cooling and lubrication and reduced the tool flank wear length and the resultant force by 56.5% and 13.5%, respectively, compared to dry condition. The improvement in machinability was more remarkable in the cryoMQL condition than in the condition where cryogenic cooling and MQL were separately applied. | Tool wear evolution and chip formation of the Ti-6Al-4V end milling under cryogenic cooling and minimum quantity lubrication conditions | 10.1007/s00170-023-12704-3 |
2024-01-01 | In this paper, the process model for cryogenic forming with macro-structured tools is analyzed regarding the continuously changing thermal conditions during the deep drawing process. For this purpose, the transient contact conditions within the macro-structure are investigated for different tool designs of the macro-structure as a function of the immersion depth and resulting contact pressure in a numerical analysis. The determination of the heat transfer coefficient between the aluminum sheet metal and the tools as a function of the contact pressure is carried out experimentally. Numerical investigations are used to determine an improved macro-structure in terms of low-heat flow and reliable suppression of wrinkling. The influence of the tool design on the temperature distribution is presented and compared with the conventional deep drawing process. | Contact Conditions and Temperature Distribution During Cryogenic Deep Drawing with Macro-structured Tools | 10.1007/978-3-031-40920-2_25 |
2024-01-01 | The large-diameter and thin-walled aluminum alloy tube has superiority in terms of weight reduction and high transmission efficiency which has been widely used in the aerospace field. However, it is a tough issue to deform a desirable bent tube with such extreme specification and small bending radius. In recent years, aluminum alloy materials have been found to show strong enhancement in both strength and ductility when deforms at cryogenic temperature (CT), which provide the cryogenic forming potential for the hard-to-bend aluminum alloy tubes. In this work, tube formability at room temperature (RT) and CT was explored. The anisotropic characterization of the thin-walled tube was realized by combining experiment and viscoplastic self-consistent (VPSC) model. The overall mechanical properties at CT are significantly improved compared to those at RT. Furthermore, a finite element model of cryogenic bending of the thin-walled 6061-O aluminum alloy tube was constructed. The results provide evidence from two aspects of wrinkling and wall thickness reduction that the thin-walled aluminum alloy tube difficult to form at RT can achieve better formability when bent at CT. The average wrinkle height decreases first from 1.182 mm at RT to 0.201 mm at −60 ℃ with 83.0% reduction, and then increases to 0.425 mm at −180 ℃. The average thickness reduction rate decreases monotonically with temperature decreasing, and the drop is fastest at −60 ℃ of 15.4% reduction. Cracks no longer appear in cryogenic bending. In terms of the effect on the two defects of wrinkling and wall thickness reduction, −60 ℃ is the temperature at which the best forming properties are obtained. | Cryogenic Forming Potential of Large Diameter and Thin-Walled Aluminum Alloy Tubular Materials | 10.1007/978-3-031-42093-1_32 |
2024-01-01 | Cryogenic centrifugal submersible pump is a core equipment that pressurizes and transports fluid with the centrifugal force generated from impeller’s rotation. Problems like cavitation and surging, attributed to the working fluid and multistage structural characteristics, negatively affect the lifespan, noise, vibration, and performance of the pump. Therefore, this study develops a pump for a general-purpose specific-speed liquified natural gas fuel-supply system. The internal flow characteristics and performance prediction were analyzed using a commercial computational fluid dynamics analysis software. The numerical analysis results demonstrated that the average head varied across all conditions, where cavitation was absent within the inducer. NPSHre was determined at a cavitation coefficient of about 1.07 and head reduction of 97 %. It was confirmed that the swirl component generated at the trailing edge had a negative effect on the impeller when the flow passed through the inducer region. Upon analyzing the existing model, we identified the problems and discussed the future research directions for improving the pump performance. | Influence of cavitation on inducer and return channels of LNG pump | 10.1007/s12206-023-1222-y |
2024-01-01 | The terahertz spectrum of paper has been measured from room temperature to cryogenic temperatures. As the paper is cooled, the main absorption lines move to higher frequencies. The same behaviour is observed for two types of paper. The spectrum at base temperature provides the most direct comparison yet with calculations made using density functional theory, which assume the studied material to be at absolute zero temperature. These unique experiments should spur the development of better theoretical models of cellulose and cognate materials. | Terahertz spectroscopy of paper to low temperatures | 10.1007/s10570-023-05663-1 |
2024-01-01 | Cryogenic frosting is a common phenomenon in the field of aerospace industry. However, for the case that the cryogenic surface is cooled from room temperature, such as a cryogenic propellant fueling to an uninsulated cryogenic tank, the frost formation process could be unique. In this paper, the density and thermal conductivity of frost deposited on the cold surface cooled from room temperature to cryogenic temperature were experimentally investigated under forced condition. Weighting method was adopted to measure the final frost density at the end of each experiment, and frost thermal conductivity distribution inside the frost layer was obtained by analyzing the temperature profile measured at different heights. The results show that the final frost density increases with air velocity and air absolute humidity and varies from 54.7 to 556.7 kg/m^3 in this study. The cooling rate in the initial cooling process exerts a certain effect on the frost structure, which could be observed by the variations of frost density. The frost thermal conductivity is layered along the thickness direction of the frost layer, but the thermal conductivity value, which has been formed at a certain height, does not change significantly with time. Moreover, correlations of frost density and frost thermal conductivity are established with ambient temperature, ambient humidity, and incoming air velocity as variables. Compared to the experimental data, the deviations of the predicted frost density and frost thermal conductivity are both within 10%. The present study could deepen the understanding on frost features in cryogenic conditions, and the established correlations provide reliable tools of estimating frost properties, which are beneficial to the design of cryogenic propellant fueling process. | Experimental Investigation on Frost Density and Thermal Conductivity Under Cryogenic Condition | 10.1007/978-981-99-8045-1_40 |
2024-01-01 | Mainly used in the automotive and aircraft industries, Al–Si-based metal matrix composites stand out with their superior tribological properties under difficult operating conditions. Machinability studies were carried out to prevent and solve the problems that may occur during the shaping of these materials. It is important to improve these composites' machinability performance and environmental impact during machining. Traditional machining fluids have a harmful effect on the environment and human life. It is critical to utilize alternate cutting fluids to eliminate these consequences. It is seen that the studies on this subject are insufficient. In this study, Al–12Si-based composites reinforced with hybrid reinforcements were milled under sustainable cooling/lubrication conditions. According to the results obtained, with cryo-LN_2 assisted cooling, surface roughness, tool wear, and cutting temperature were reduced, resulting in better performance than dry machining. It was also determined that energy consumption was reduced with cryo-LN_2 compared to dry machining. As a result, the cryogenic cooling technique proved to be the best option for the sustainable manufacturing of Al–12Si-based hybrid composites. | Machining and Energy Aspect Assessment with Sustainable Cutting Fluid Strategies of Al–12Si Based Hybrid Composites | 10.1007/s40684-023-00544-1 |
2024-01-01 | This paper investigates the leakage characteristic of a non-contact cryogenic seal applied through experiment and CFD analysis. Plain seal (PS), labyrinth seal (LS), and floating ring seal (FRS) were designed for leakage performance test of cryogenic environment. ANSYS Fluent (18.2) was used for creating the flow field of the sealing unit for leakage performance analysis. In order to validate the CFD analysis results, the leakage experimental performance test was also conducted in a cryogenic environment. To create a cryogenic environment, liquid nitrogen (83K) was injected into the test chamber at 0.5 bar, and the test time for each seal was 5,000 s. The results show that among the three types of seals, the FRS had the smallest leakage and the amount of leakage converged quickly. It was confirmed that the largest turbulent kinetic energy was generated when an FRS was used. Also, FRS effectively reduced leakage compared to PS and LS due to the characteristic that clearance changes according to pressure difference. After the leakage performance test, the wear characteristic according to the seal shape was analyzed through surface roughness measurement. In the case of PS, the wear of the surface progressed considerably more than the FRS. Inadequate fluttering adversely affects the wear and leakage performance of the seal. It was found that the wear of PS due to thermal contraction accelerated the friction, and in contrast, the FRS had less friction even with thermal contraction. | Experiment and CFD Analysis of Plain Seal, Labyrinth Seal and Floating Ring Seal on Leakage Performance | 10.1007/978-3-031-40455-9_32 |
2023-12-20 | Considering the current demands for resource conservation and energy efficiency, innovative machining concepts and increased process reliability have a significant role to play. A combination of martensitic hardening of the subsurface and near-net-shape manufacturing represent a great potential to produce components with wear-resistant subsurfaces in an energy- and time-saving way. Within the scope of the present study, the influence of cryogenic machining of metastable austenitic steel on the martensitic transformation and surface quality was investigated. Different cooling strategies were used. A soft sensor based on eddy current in-process measurements was used to determine and subsequently affect the martensitic transformation of the subsurface. The feed rate and component temperature were identified as significant factors influencing the martensitic transformation. However, a high feed rate leads to an increase in surface roughness, and thus to a reduction in component quality. For this reason, a roughing process for achieving maximum martensitic transformation was carried out first in the present study and then a reduction in the surface roughness by maintaining the martensitic subsurface content was aimed for by a subsequent finishing process. With the knowledge generated, a dynamic process control was finally set up for designing the turning process of a required subsurface condition and surface quality. | A process-reliable tailoring of subsurface properties during cryogenic turning using dynamic process control | 10.1007/s11740-023-01244-0 |
2023-12-14 | The article introduces a newer hybrid method (HAIS-GA) of optimizing and choosing the ideal machining parameters for cryogenic processing. It depends on two late methodologies genetic algorithm (GA) and artificial immune system (AIS), which are connected to numerous troublesome combinatorial streamlining issues with specific qualities and shortcomings. These developmental calculations are proposed to find the best arrangement of process factors for the clashing prerequisites in multi objective capacities. Hybrid model optimization also comes with challenges, such as selecting the right combination of techniques, tuning parameters, potential increases in complexity, and the need for expertise in multiple optimization methods. The key reason for this hybrid approach (HAIS-GA) is the improvement in the results that is achieved due to the characteristics of GA and AIS. Three test functions are employed to compare the outcomes in terms of these functions' ability to achieve the lowest value. Cryogenic processing is used to validate the optimised values that were obtained. The attained results showcase that HAIS-GA approach, in conclusion exhibits a more favourable minimal objective function within a reasonable duration. Due to the nature of Unrestricting to local optima, and it being self-adaptive HAIS-GA provides better result compared to GA and AIS. Based on the least value of the objective function and time for each method. | Optimization of cryogenic processing parameters based on mathematical test functions using a newer hybrid approach (HAIS-GA) | 10.1007/s12008-023-01599-9 |
2023-12-13 | By soaking polycaprolactone (PCL) scaffolds in a PCL solution, the surface properties of the scaffolds can be modified to improve early bone formation. In the presented study, scaffolds composed of PCL and hydroxyapatite nanowires (HAW) were fabricated by cryogenic extrusion printing. The scaffold surface was subsequently modified by self-induced crystallisation. In this study, the synthesized HAW and scaffolds were analyzed through X-ray powder diffraction (XRD), Fourier transform infrared (FTIR), and scanning electron microscopy (SEM). Additionally, the synthesized HAW was characterized using transmission electron microscopy (TEM). The findings indicate that the surface of PCL-HAW scaffolds developed lamellar crystals, resulting in surface roughness. Furthermore, the results of the biological experiments show that PCL-HAW scaffolds with a layered crystal structure on their surface have the potential to stimulate both proliferation and differentiation of osteogenic precursor cells (MC3T3-E1). . | Cryogenic Extrusion Printing of PCL-HAW Scaffolds and Self-induced Crystalline Surface Modification | 10.1007/s12221-023-00438-8 |
2023-12-02 | The temperature–time-property (TTP) curve of the cryogenic deformed 6061 aluminum alloy was fitted in this study, and the sensitive temperature range was determined through interrupted quenching experiments. The precipitation behavior during isothermal treatment of the cryogenic deformed samples was observed and analyzed by the differential scanning calorimetry (DSC), optical microscope (OM), and transmission electron microscope (TEM), and the premature precipitation mechanism during isothermal treatment was discussed in detail. The results revealed that the critical time for a 5% drop in hardness at the nose temperature (400 °C) was 25.2 s. Furthermore, the sensitive temperature range was determined to be from 360 to 420 °C. At 400 ℃, the supersaturated solution transformation rate reached its maximum, and coarse β equilibrium phases were rapidly precipitated in the grain. However, when the temperature was outside the sensitive range, the transformation rate decreased, and several β" and β′ phases were observed, indicates a lower degree of premature precipitation of the alloy. The high sensitivity at nose temperature can be attributed to the relatively high nucleation and growth rates of phases. Based on the experimental results, the cooling rate at the sensitive temperature range should be increased, while the cooling rate from the solution temperature to 420 °C should be properly decreased during the quenching process to obtain relatively high mechanical properties and low residual stresses. Graphical Abstract | Study on Quench Sensitivity and Premature Precipitation Behavior of the Cryogenic Deformed 6061 Aluminum Alloy | 10.1007/s12540-023-01565-w |
2023-12-01 | The present research examines cryogenic coolant's performance and effect on thrust force, burr height, cutting temperature, and surface finish while drilling nano SiC reinforced Al matrix composites over dry machining. The vertical computer numeric control (CNC) machining center assisted with cryogenic LN_2coolant is used to conduct the drilling tests with a carbide drill of 10 mm having 90°, 118°, and 135° point angles. Taguchi L_18 orthogonal array is employed in planning the drilling experiments. A grey-based ANFIS algorithm was implemented to optimize drilling parameters: feed rate, spindle speed, drill point angle, and wt% of nano SiC. The reduced friction in cryogenic LN_2 resulted in lower temperature and surface roughness. After the drilling experiments, the machined surface is further investigated through a scanning electron microscope (SEM). This investigation revealed that applying cryogenic LN2 coolant in drilling Al matrix composites reinforced with SiC nanoparticles is an alternate method to enhance the drilling performance. | Application of grey-ANFIS system to optimize the drilling characteristics of nano SiC reinforced Al matrix composites | 10.1007/s12008-023-01328-2 |
2023-12-01 | On the basis of the weakly compressible assumption, large-eddy simulation of a high-speed centrifugal pump is performed at a rotational speed of 9685 r/min and flow rate of approximately quarter load (0.23 Qd). Three cryogenic media, namely, liquid methane (MM), liquid nitrogen (MN), and liquid oxygen (MO), are used. Results show that many of the internal flow characteristics derived and validated for normal-temperature water still hold for cryogenic media. Pump efficiency, maximum density deviation, and total entropy generation rate increase with the increase in the reference density. The dominant frequencies of the pressure spectrum are 12 and 6 times the rotation frequency and insensitive to the cryogenic media. The average amplitude of the first-order dominant frequency between MN and MO deviates from that of MM by approximately 10 %. The maximum deviations of the average amplitudes of second-order dominant and axial frequencies are 34.9 % and 32.3 %, respectively. The variation in standard deviation exceeds 40 % for all cryogenic media. | Effects of cryogenic medium on the weakly compressible flow characteristics of a high-speed centrifugal pump at a low flow rate | 10.1007/s12206-023-1125-y |
2023-12-01 | In this work, the influences of Deep Cryogenic Treatment (DCT) at − 196 °C for 24 h on heat treated Electroless Nickel- Phosphorous (NiP)-coated substrates are studied. Adhesion of coating, structure and composition of coating and corrosion properties of the coating have been evaluated. AISI 1020 steel samples are coated with NiP by means of an autocatalytic reaction along with mechanical stirring. The coated samples are then heated to 400, 600 and 800 °C to form an interdiffusion layer. Then, DCT is performed at −196 °C with a soaking time of 24 h. Micro hardness, adhesion test, x-ray diffraction (XRD), scanning electron microscopy (SEM), and electrochemical corrosion tests are used to evaluate the coating surface. Scanning electron microscope analysis and XRD of the DCT NiP substrate ensured the formation of ß -phase precipitates. The examination of coating adherence is judged to be sufficient and acceptable for DCT NiP as per VDI 3198 standard. A minor variation in micro hardness is observed after DCT with a gradual increase in 2%. This ensures that, DCT does not affect the mechanical properties of heat treated NiP samples. However, accelerated corrosion test E _corr is displaced in the direction of the active field for DCT NiP samples from − 0.171 to −0.020 mV this increase in corrosion resistance may be due to phase transformation. In addition to this, reduced i_corr showed increase in corrosion resistance of the substrate. Similarly the corrosion resistance identified through Electrochemical Impedance Spectroscopy (EIS) showed an overall increase in 9% in corrosion resistance after DCT and compared with corrosion morphology. It creates a new avenue in the field of materials in aerospace and satellite applications. | Influence of Deep Cryogenic Treatment on the Properties of Electroless Nickel-Phosphorous Coating | 10.1007/s11665-023-08842-0 |
2023-12-01 | Plasmonic nanoparticles exhibit distinct nearfield properties that offer potential advantages for label-free biosensing applications. By generating strong interactions between light and matter, these nanoparticles can be employed to detect the presence of analytes through monitoring spectral variations within the plasmonic resonances resulting from changes in the biomolecules on their surface. Various fabrication methods have been introduced in the literature to produce such particles. In this study, precise control over the shape, size, and distribution of nanoparticles is crucial to effectively excite plasmonic resonances with desirable optical properties. Traditionally, the vacuum deposition technique has been widely used to create nanoparticles with good crystalline properties and uniform particle distribution at high substrate temperatures (300 K). However, this method exhibits reduced surface or volume diffusion of particles at lower substrate temperatures, leading to a decrease in the particle size of the metal thin films. Additionally, surface homogeneity deteriorates due to the shadowing effect when dealing with thicker film coatings. To overcome these limitations, we propose a cryogenic temperature method, in which vacuum evaporation is performed at low substrate temperatures (200 K). Our method demonstrates the ability to produce nanoparticle systems with homogeneous particle size distribution and high structural quality. To evaluate the efficacy of our approach for biosensing applications, we compared two silver (Ag) nanoparticle systems prepared using the classical vacuum deposition technique (300 K) and our cryogenic temperature method (200 K) in terms of their structural and optical properties. We showed that our method enables the excitation of plasmonic resonances with narrower linewidths compared to the classical evaporation technique. Moreover, our method allows for the realization of nanoparticles with more controlled dimensions, which are homogeneously distributed over the substrate surface. This characteristic facilitates the generation of surface plasmon excitations associated with large local electromagnetic fields that extend extensively into the volume surrounding the sensing surface. Therefore, our method facilitates stronger light-matter interactions compared to the classical technique, resulting in enhanced refractive index sensitivity for label-free biosensing applications. We conducted sensing experiments using bulk solutions with different refractive indices to demonstrate the superior refractive index sensitivity of our cryogenic temperature method. Our findings indicate that our method produces plasmonic nanoparticle systems with higher refractive index sensitivities. Furthermore, when functionalizing the metal surface with protein mono- and bilayers, our method yields larger spectral shifts within the plasmonic resonances compared to the classical vacuum deposition technique. This indicates that our method has the potential to serve as a highly sensitive and label-free plasmonic biosensing platform without the need for expensive, slow, and complex fabrication techniques that require a sophisticated clean-room infrastructure. In summary, we believe that our method opens up possibilities for the development of advanced plasmonic biosensing platforms with exceptional sensitivity. | Enhancing Label-Free Biosensing With Cryogenic Temperature-Induced Plasmonic Structures | 10.1007/s11468-023-01963-1 |
2023-11-28 | Cryogenic fracturing with liquid nitrogen (LN_2) offers the benefits of reducing the water consumption and adverse environmental impacts induced by water-based fracturing, as well as potentially enhancing the fracture complexity. A coupled thermo-hydro-mechanical-damage (THMD) model based on finite element method (FEM) was established and implemented into COMSOL Multiphysics to study the key mechanisms governing the damage evolution law and breakdown pressure in shale during cryogenic fracturing. The numerical results were compared with analytical and experimental data in order to validate the numerical simulation. Sequentially, the shale reservoir was exposed to low-temperature LN_2 for a certain time and then fractured by gaseous N_2. Effects of various key parameters, including LN_2 treatment duration, LN_2 injection rate, reservoir temperature, and shale bedding direction, on damage evolution law and breakdown pressure were investigated. Results demonstrate that, as a pre-fracturing fluid injected into the borehole, the low-temperature LN_2 could dramatically reduce the breakdown pressure under the action of nitrogen fracturing, resulting in a more complex network of fractures. Hence, the bedding inclination performs a critical role on the direction of crack propagation that not only the effective connected damage region but also the breakdown pressure decrease with increasing the bedding inclination angle. Consequently, the proposed numerical coupling model can play a vital role on the optimization of the key parameters of the field scale during cryogenic fracturing processing. | Coupled simulations on fracture network evolution during nitrogen fracturing after liquid nitrogen pre-conditioning in shale | 10.1007/s10064-023-03495-8 |
2023-11-16 | The residual stresses generated during the solution treatment of large cylindrical aluminum alloy components can impact the dimensional accuracy of structural components and even lead to premature failure of the parts. To reduce the residual stresses generated during the solid solution treatment of aluminum alloys, a new method combining cryogenic control system treatment and oil bath aging was designed. The residual stresses of the specimens were measured using x-ray diffraction and blind hole methods. Changes in the microstructure were observed through scanning electron microscopy and transmission electron microscopy, which revealed the relationship between the dislocation density and the residual stresses of aluminum alloys. The results indicate that this novel treatment method reduced residual stresses by 86%. The reduction in dislocation density and the dispersion of delicate secondary phases through precipitation are the primary intrinsic factors attributed to the reduction of residual stresses in the aluminum alloy through this new treatment method. The finely dispersed second phase helps improve the hardness of the aluminum alloy. | Modification of Residual Stress and Microstructure in Al-Cu-Mg Alloy by Cryogenic Aging Treatment | 10.1007/s11665-023-08956-5 |
2023-11-13 | High Entropy Alloys (HEAs), a breakthrough in alloy design incorporating multiple elements in an equiatomic or near equiatomic ratio, were envisioned in the latter half of the twentieth century and realized at the start of the twenty-first century. These materials are relatively new and must be extensively explored for their applicability in structural and functional applications. We have developed a product using an Al-containing Cantor alloy for space applications to withstand cryogenic temperature. We report the tensile properties of the (CoCrFeMnNi)_95Al_5 cast product at two different cryogenic temperatures (77 and 90 K). The alloy shows an optimum combination of strength and ductility, which increases with decreasing temperature, satisfying the requirement for space application. The detailed microstructure analysis of the deformed samples near the fractured tip reveals the formation of multivariant deformation twins along with a dense dislocation network, dislocation cells, and walls, leading to the strengthening and strain hardening, allowing to achieve simultaneous improvement of strength and ductility. | Product Development Using (CoCrFeMnNi)_95Al_5 High Entropy Alloy for Cryogenic Application | 10.1007/s41403-023-00434-7 |
2023-11-01 | This study presents the affects of cryogenic treatment on flank wear (Vb) and surface roughness (Ra) in machining 41Cr4 steel with shallow (SCT (15 h at −80 °C)) and deep (DCT (15 h at −196 °C)) cryogenically treated carbide tools. The study revealed that the cryogenic treatment increases the hardness and wear resistance of coated carbide tools and improves the surface roughness, thanks to the changes in the microstructure. The η-phase is approximately 17.5 and 24.64% higher in the shallow and deep cryogenically treated tool's microstructure than in the untreated tool (U). The best machining performance was founded with the deep cryogenically treated cutting tool. Compared to the untreated tool, shallow and deep cryogenic treatment increased the hardness of the cutting tools by approximately 8.66 and 10.17%. Compared to the untreated cutting tool, the deep cryogenically treated tool was less worn at rates ranging from 13.04 to 18.60% and provided a lower average surface roughness between 2.49 and 20.15%. With increasing feed rate and cutting speed, the amount of cutting tool flank wear also increased. While the surface roughness values decreased slightly with increasing cutting speed, the increasing feed rate caused the surface roughness to increase significantly. The analysis of variance results showed that the most significant parameter on the cutting tool flank wear was heat treatment with a rate of 67.34%, and the most influential parameter on the surface roughness was the feed rate with a rate of 96.33%. | Effects of Shallow and Deep Cryogenic Treatment on Tool Flank Wear and Surface Roughness in Machining 41Cr4 Steel | 10.1007/s11665-023-07866-w |
2023-11-01 | This study analyzes the influence of cryogenic treatments, before the pre-tempering treatment on the microstructure, and the mechanical properties of the H13 tool steel. The H13 tool steel was subjected to the shallow cryogenic treatment SCT (at –80 °C for 24 h) and deep cryogenic treatment DCT (at –185 °C for 24 h) between hardening and pre-tempering processes (at 650 °C for 15 min). Alternatively, the tool steel was exposed only to the hardening and pre-tempering processes. The characterization of the microstructures and phase transformations of the specimens was established via scanning electron microscopy and X-ray diffraction, respectively. The mechanical behavior of the treated H13 tool steel was estimated using the Rockwell hardness and abrasive wear tests. Upon completion of the quenching treatment, the H13 tool steel presented the formation of fine, thin crystals of lath-shaped martensite, while the subsequent pre-tempering treatment formed a microstructure with wider martensite laths than the as-quenched state. The sub-zero treatments on the H13 tool steel promoted several phenomena, such as the martensitic transformation, the refinement of martensite laths, and the formation of large and fine carbides dispersed in the whole microstructure. The specimens exposed to SCT and DCT achieved an improvement in hardness values due to structural changes, which also contributed to a better wear resistance (17 and 25%, subsequently) in comparison with the tool steel exposed exclusively to the pre-tempering treatment. Meanwhile, the failure mechanisms on worn surfaces of the treated H13 tool steel were micro-cutting and pitting, which were developed during the interactions among the specimen surfaces-abrasive particles-rubber wheel. | Influence of Heat and Cryogenic Treatments on the Abrasive Wear Behavior of H13 Tool Steel | 10.1007/s11665-023-07865-x |
2023-11-01 | For the development of upper stage rocket engines with laser ignition, the transition of oxidizer and fuel from the pure cryogenic liquid streams to an ignitable mixture needs to be better understood. Due to the near vacuum conditions that are present at high altitudes and in space, the injected fuel rapidly atomizes in a so-called flash boiling process. To investigate the behavior of flashing cryogenic jets under the relevant conditions, experiments of liquid nitrogen have been performed at the DLR Lampoldshausen. The experiments are accompanied by a series of computer simulations and here we use a highly resolved LES to identify 3D effects and to better interpret results from the experiments and existing 2D RANS. It is observed that the vapor generation inside the injector and the evolution of the spray in the combustion chamber differ significantly between the two simulation types due to missing 3D effects and the difference in resolution of turbulent structures. Still, the observed 3D spray dynamics suggest a suitable location for laser ignition that could be found in regions of relative low velocity and therefore expected low strain rates. Further, measured droplet velocities are compared to the velocities of notional Lagrangian particles with similar inertia as the measured droplets. Good agreement between experiments and simulations exists and strong correlation between droplet size and velocity can be demonstrated. | Investigating 3-D Effects on Flashing Cryogenic Jets with Highly Resolved LES | 10.1007/s10494-023-00485-4 |
2023-11-01 | The presented work is a continuation of the development of a computational and experimental method for determining the thermophysical characteristics (TPC) of the stator coils of a generator operating with the use of the phenomenon of high-temperature superconductivity (HTSC). The paper considers algorithms for identifying heat transfer models in the composite material of the stator coil winding. Using the discovered thermophysical properties, it is planned to study the electrothermal interaction in a high-temperature superconductor before its transition to a superconducting state. There is a significant variety of methods for solving the problems of identifying mathematical models of heat transfer, in particular, of determining the thermophysical characteristics of composite materials. As a result of the analysis of alternative methods for solving the identification problem, the iterative regularization method is used in this work. | Identification of Mathematical Models of Heat Transfer of HTSC Coils. 2. Algorithm for Solving IHP and the Results of Experimental Data Processing | 10.1007/s10891-023-02807-9 |
2023-11-01 | The inclusion of nanoparticles makes the composite not only stronger but also lighter and highly resistant towards wear among many other positive attributes. However, the high hardness and abrasive characteristics of the composites make machining a formidable task. Hence to surmount these challenges, various coolant conditions have been entailed like dry machining, flood cooling, minimum quantity lubrication (MQL), and cryogenic (cryo) CO_2 cooling. This investigation encompasses the influence of diverse coolant techniques during the machining of as casted aluminium with nano silicon carbide (Al/n-SiC) composite. This study further incites the analysis of the machining temperature, surface characteristics, flank wear, and chip morphology under each coolant techniques. The outcomes of this investigation furnish a comprehensive understanding of the impact of distinct coolant environments on the machining performance of Al/n-SiC composite. The cutting temperature under cryo-CO_2 was found to be lowered by 41–47%, 15–21%, and 8–12% when compared to the usage of dry, flood, and MQL, respectively. The study unveils that cryo-CO_2 cooling developed the lowest machining temperature, followed by MQL, flood cooling, and dry machining. Furthermore, cryo-CO_2 cooling and MQL exhibited the best outcome in terms of flank wear and surface characteristics. The verdicts of this investigation suggest the use of cryo-CO_2 cooling and MQL makes eloquent improvement in the machining performances of Al/n-SiC composites. | Novel use of cryogenic cooling conditions in improving the machining performance of Al 8011/nano-SiC composites | 10.1007/s00170-023-12382-1 |
2023-11-01 | Safe storage and transportation of liquid oxygen (LOX) are critical for many engineering, medical, and defense applications. Double-walled, vacuum-insulated cryogenic tanks are commonly used, but they require supports that minimize heat transfer while bearing mechanical stresses. This study examines a novel polyamide-steel composite support for cryogenic tanks using COMSOL simulations. The significance lies in improving storage by reducing heat flux to LOX. The study also evaluates the effects of dynamic loading, resulting from mechanical shocks three times larger than the mass of the inner shell carrying LOX, applied to the ends of the internal supports. The significant contributions of this research lie in two main areas. Firstly, the study demonstrates the advantages of the new support design, particularly its enhanced ability to minimize heat transfer from the external environment to the cryogenic tank, thereby contributing to improved temperature control and safety. Secondly, the developed composite supports exhibit superior heat transfer characteristics, displaying efficiency in both static and dynamic loading conditions. Results demonstrated that the composite support reduced heat transfer compared to conventional designs under static and dynamic loads. This new support design enables safer LOX storage by limiting temperature increases. The coupled thermal–mechanical modeling methodology provides an effective tool for optimizing support designs in cryogenic systems. | A numerical transient thermomechanical modeling of the metal-polyamide internal supports for cryogenic vessels | 10.1007/s10973-023-12469-7 |
2023-11-01 | A novel system formed by a Microwave Superconducting Quantum Interference Device (SQUID) Multiplexer ( $$\mu$$ μ MUX) and a room temperature electronics employs frequency division multiplexing (FDM) technique to read out multiple cryogenic detectors. Since the detector signal is embedded in the phase of the SQUID signal, a Digital Quadrature Demodulator (DQD) is widely implemented to recover it. However, the DQD also generates a signal that aliases into the first Nyquist zone affecting the demodulated detector signal. In this work, we demonstrate how this spurious signal is generated and a mathematical model of it is derived and validated. In addition, we discuss different proposals to improve the attenuation of this undesired signal. Lastly, we implement one of the proposals in our readout system. Our measurements show an enhancement in the spurious signal attenuation of more than 35 dB. As a result, this work contributes to attenuate the spurious below the system noise. | Aliasing Effect on Flux Ramp Demodulation: Nonlinearity in the Microwave Squid Multiplexer | 10.1007/s10909-023-02993-z |
2023-11-01 | The use of additive manufacturing (AM) has increased significantly in recent years, primarily to produce critical and small components with complex geometry that cannot be manufactured through conventional processes. The application of a secondary process, such as machining, improves the surface finish and alters the residual stresses generated during the AM process. The objective of this study was to investigate the effect of different types of cutting fluids on the machined surface roughness and residual stresses of components produced through AM and conventional rolling processes of AISI 316L. A carbide tool was used during the milling process, and three types of cutting fluids were examined: dry machining, flooded cutting fluid, and cryogenic cooling. Residual stresses were evaluated using X-ray diffraction, while surface roughness was determined using an interferometer microscope. The surfaces were also analyzed through scanning electron microscopy (SEM). The best results for surface roughness and residual stress were achieved with the use of cryogenic cooling, with SEM revealing the presence of adhered material particles on the surface. A correlation was established between residual stress and surface kurtosis roughness, represented by the R _KU parameter, and the increase in kurtosis could be associated with an inversely proportional increase in the parallel residual stress. This study provides valuable insights into the impact of the cutting fluid type on the quality of the surface and residual stress of machined components produced through AM and conventional rolling processes. Graphical abstract | Effect of cryogenic cooling on residual stresses and surface finish of 316L during hybrid manufacturing | 10.1007/s00170-023-12380-3 |
2023-11-01 | Geometrical inaccuracy is one of the electric discharge machining (EDM) errors and is mainly influenced by the dielectric being used during the operation. The non-conventional machining processes are opted over traditional machining operations due to the greater strength of Ni-based superalloy, specially, Inconel 617 (IN617). But still, there is a need to upgrade the dielectric fluid to minimize the overcut. Therefore, this study uses a combination of surfactant-added dielectrics of transformer oil and cryogenically treated (CT) electrodes (copper and brass). One of the exceptional benefits of applying the cryogenic treatment on the electrodes is that it refines the grain size of the electrode which helped in the regular sparking and reduced the dimensional inaccuracy throughout the EDM operation. A set of 20 experiments under the full factorial design technique was implemented. The experimental results have been explained with process physics, and along with simulation to explore the mechanism of machining with mathematical expressions. The machining capabilities of CT electrodes provided greater dimensional accuracy by an average of 17.1% compared to non-CT electrodes. CT brass provided the minimum dimensional inaccuracy (0.023 mm) in T-20. However, the non-CT copper electrode showed the lowest overcut (0.134 mm) obtained transformer oil without the addition of surfactant. The modeling was also performed to measure the crater sizes produced during the machining of Ni-based superalloy. The simulation results revealed that the mean absolute divergence between the current simulation findings and the ones provided in the literature was approximately equal to 5–7%. | Mathematical modeling and experimental evaluation of superalloy EDM using cryogenically treated electrodes and transformer oil-based dielectrics: a correlation study | 10.1007/s00170-023-12398-7 |
2023-10-30 | This paper investigates the mechanical response and the mechanisms of failure of an ultra-high molecular weight polyethylene under service at cryogenic temperature. The service temperature $$T_\textrm{s}$$ T s being about $${50}\,^\circ {\text {C}}$$ 50 ∘ C below its glass transition temperature $$T_\textrm{g}$$ T g , the study focuses on the experimental techniques to determine both the glass transition temperature $$T_\textrm{g}$$ T g and the ductile–brittle transition temperature (DBTT). $$T_\textrm{g}$$ T g was estimated by dynamic mechanical thermal analysis (DTMA) and contrasted with the glassy–rubbery transition defined by using the Young’s modulus issued from monotonic tensile tests on smooth specimens at room and low temperature and various cross-head speeds. Concerning the DBTT, two estimators of the transition, based on the fracture surface and the up-to-failure data, were studied. An operating diagram (temperature/cross-head speed) including the probability of ductile failure and both the rubbery and glassy domains is proposed. This diagram aims at finding an optimal compromise of the material response combining stiff versus soft with brittle versus ductile behaviour. | Dependence on strain rate of the glass and ductile-to-brittle transition temperatures of an ultra-high molecular weight polyethylene used at cryogenic temperature | 10.1007/s00161-023-01261-5 |
2023-10-29 | An effective analytical method using NTM-COFs on-line pass-through cleanup method and ultra-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) to simultaneously quantify 12 illicit drugs (norketamine, ketamine, codeine, cocaine, methamphetamine, 3,4-methylenedioxyamphetamine, 3,4-methylenedioxymethamphetamine, amphetamine, benzoylecgonine, 6-acetylmorphine, morphine and methadone) in hair sample was developed and validated. The hair sample was extracted with 0.3% formic acid-acetonitrile (v/v) and passed through the nano-titania-modified covalent organic frameworks (NTM-COFs) pre-column to reduce the matrix effect caused by hair specimen. Under the optimal conditions, satisfactory extraction efficiency was obtained for 12 illicit drugs with recoveries between 84.6% and 108.8%. The proposed method was linear for each analyte with correlation coefficients over 0.9926. The limits of detection and limits of quantification for 12 illicit drugs were in the range of 0.012–0.558 ng/g and 0.036–1.860 ng/g, respectively. Acceptable precision and accuracy were also achieved with relative standard deviations values below 9.92% and relative error values below 15.4%. The analytical method was successfully applied to real hair samples from suspected drug abusers, which was proved to be reliable and robust for drug screening in forensic toxicology. | Simultaneous determination of 12 illicit drugs in hair sample by the nano-titania-modified covalent organic frameworks (NTM-COFs) on-line pass-through cleanup followed by UPLC-MS/MS | 10.1007/s11696-023-03124-4 |
2023-10-13 | A high-entropy alloy with an atomic composition of Fe_40Mn_15Cr_20Ni_22Ti_3 with outstanding strength–ductility synergy induced by titanium additions was successfully developed. At room temperature, its ultimate tensile strength can reach 1089 MPa and still maintain 21% elongation. Moreover, at low temperature of 77 K, its ultimate tensile strength and elongation have been increased to 1285 MPa and 35%, respectively. After careful analysis, it is found that the cause for the large increase in elongation is the decrease of the stacking fault energy at low temperature, which leads to the deformation mechanism of the alloy to change from dislocation wave slip to plane slip. In addition, the precipitation strengthening and grain boundary strengthening induced by chrome-rich σ precipitates are the main strengthening contribution. | A Cobalt-Free High-Entropy Alloy with Excellent Mechanical Properties at Ambient and Cryogenic Temperatures | 10.1007/s11665-023-08799-0 |
2023-10-01 | The operation mode, sequences, and logic of the cryogenic distribution system for Superconducting Linac 3 of RAON are described. The systematic construction of the cryogenic distribution system is introduced, and the roles of transfer lines and instruments are explained. The flow of operation modes and the operation strategies in each operation mode are designed with consideration of the system structure, the requirement of the cryogenic system, and the cryogenic fluid properties. The operation modes are grouped into cool-down process, warm-up process, and steady states in normal operations. The step-by-step operation sequences of the instruments in each operation mode is clarified. In the cryogenic distribution system of RAON, the thermal shield circuits for all cryo-modules are cooled down concurrently, and the fluid mass flow rates are controlled by using virtual flow meters. The most important tasks during the cool-down process of the superconducting cavities are to shorten the cool-down time and keep the steady and low pressure inside the cavities. The cold helium circuits (the SHe, GHe, and VLP lines) are cooled down one by one for the cryo-modules from 300 to 4.5 K. After that, all the HWR cavities are pumped down to 36 mbar at the same time to further cool down to 2.05 K. The warm-up process from 2.05 to 4.5 K is operated without emptying the reservoirs. The cryogenic plant and the CDS are warmed up together by circulating the helium gas. | Design of operation logic for SCL3 cryogenic distribution system for RAON | 10.1007/s40042-023-00843-5 |
2023-10-01 | The paper presents the role of in-process cryogenic cooling in the burnishing process carried out on high velocity oxy-fuel (HVOF) thermal spray coating (WC-10Co-4Cr). The work on the same coating on dry burnishing with a novel grinding wheel-shaped tool was published earlier. The average normal burnishing forces, measured with the help of dynamometer, were more than thrice the tangential forces during the cryogenic burnishing with the same tool. The burnishing process not only modified the surface but also the cross-section as the micro-hardness in the cross-section was also more in the cryogenic burnished specimen. The decrease in the surface porosity and the roughness of the HVOF thermal spray coating (WC-10Co-4Cr) after cryogenic burnishing was not as much as reported after dry burnishing. The compressive residual stresses, as determined through XRD, were more on the cryogenic burnished surface as compared to those on HVOF as-sprayed surface, but lesser than those reported for dry burnished. The cryogenic burnished specimens performed much better in both oblique and normal impact air-jet solid particle erosion (SPE) testing, than HVOF as-sprayed coating. In spite of having higher porosity, as compared to that reported for dry burnished specimens, the cryogenic burnished specimens performed better against SPE due to higher compressive residual stresses. | Effect of In-process Cryogenic Cooling in the Burnishing Process on the Solid Particle Erosion Behavior of HVOF Cermet Coating | 10.1007/s11666-023-01632-z |
2023-10-01 | A novel method for direct high-throughput analysis of multi-elements in cerebrospinal fluid (CSF) samples by laser ablation inductively coupled plasma mass spectrometry with an aerosol local extraction cryogenic ablation cell (ALEC-LA-ICP-MS) was developed. Microliter-level CSF samples were frozen by a designed cryogenic ablation cell and directly analyzed by laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) without time-consuming pretreatment. Compared with the precision obtained at room temperature (20℃), that obtained at low temperature (− 25℃) was significantly improved; the RSDs were reduced from 8.3% (Zn) to 32.6% (Mn) to 2.2% (Pb) to 6.5% (Mn) with six times parallel determination. To meet the analytical requirement of the micro-volume CSF samples, the laminar flow aerosol local extraction strategy was adopted to improve the transmission efficiency of aerosols, and the signal intensity was increased by four times compared with the standard commercial ablation cell. The standard solution with 0.4% bovine serum albumin (BSA) matrix was used as matrix-match external standard, and Rh was added into the samples as internal standard. The limits of detection (LODs) ranged from 0.17 μg·L^−1 (Mn) to 8.67 μg·L^−1 (Mg). Standard addition recovery experiments and the determination of CRM serum L-1 and L-2 were carried out to validate the accuracy of the method; all results indicated there were excellent accuracy and precision in the proposed method. The matrix-scanning function in the GeoLas software combined with the microwell plate realizes the high-throughput automatic analysis. Twenty-four CSF samples from different patients were determined; the results showed that there might be a correlation between the metal elements in CSF and the diseases, which means that the proposed method has potential in the diagnosis of neurological diseases. Graphical Abstract | Direct multi-elemental analysis of cerebrospinal fluid samples by LA-ICP-MS employing an aerosol local extraction cryogenic ablation cell | 10.1007/s00216-023-04878-2 |
2023-10-01 | Abstract Creation of an efficient system for the frequent delivery of cryogenic fuel targets (CFT) to the focus of a powerful laser facility is one of the key directions of research in inertial confinement fusion (ICF). The paper discusses prospects for the creation of a ring magnetic system based on the contactless acceleration of a levitating CFT carrier made of high-temperature type II superconductors (HTSC), up to specified injection velocities of 200–400 m/s. For this purpose, the temperature dependence of the magnetic moment of HTSC tapes in the range Δ T = 10–92 K was studied, prototype experiments on the acceleration of HTSC carriers at T ~ 80 K due to an external action on them with a frequency of ~1 Hz were carried out, and the speed for the stall of HTSC carriers from a circular trajectory were calculated. The calculation results are in good agreement with the experiment, which makes it possible to estimate the parameters of the ring magnetic accelerator for the operating temperature of the CFT injector T ~ 17 K. It is shown that the method proposed is promising for the creation of systems for noncontact delivery of CFT based on the principles of levitation and subsequent injection of CFTs into the center of the ICF reactor chamber at the required speed. The results of planning a new series of experiments are presented: acceleration of an HTSC carrier followed by injection of a surrogate target into the chamber of the GARPUN (LPI) KrF laser. | HTSC Maglev Ring System for Noncontact Acceleration and Injection of Cryogenic Fuel Targets into the Laser Focus of an ICF Facility | 10.3103/S1068335623170025 |
2023-10-01 | The effect of heat treatment and cryogenic treatment on the microstructure, tensile properties, and microhardness of the rolled (R) AZ31B magnesium alloy was investigated. AZ31B alloy was heated, shallow and deep cryogenically treated (DT) at 150, 250, 350, − 82, and − 190 °C for 1, 15, and 72 h. The superior microhardness, yield, and tensile strength were obtained for DT AZ31B alloy. The grain refinement, Mg_17Al_12precipitation formation, and better peak intensity ratio was noted for DT specimen. The heat treatment temperature of 250 °C-1 h (HT2) enhanced the elongation of AZ31B alloy. The fracture mode of the R specimen was completely dominated by both ductile and brittle fractures. The tensile fracture present in the DT specimen was a ductile fracture, which was characterized by the formation of fine dimples and fewer cleavage facets. The heat and cryogenic treatments enhanced the microhardness and tensile properties of the rolled AZ31B Mg alloy. | Effect of Heat Treatment Conditions and Cryogenic Treatment on Microhardness and Tensile Properties of AZ31B Alloy | 10.1007/s11665-022-07760-x |
2023-10-01 | A transimpedance amplifier working at a temperature around 50 K has been developed. The design of the amplifier is targeted to use specifically in dry dilution refrigerators for measuring quantum devices. Electrical characteristics such as input noise, bandwidth, and gain of several commercial operational amplifiers (op amps) operating at 77 K were evaluated. From a screening process, the op amp OPA827 was chosen for the benchmarking of a cryogenic transimpedance amplifier. The conductance of a quantum point contact (QPC) at 100 mK was measured in a dry dilution refrigerator in order to compare the cryogenic and room temperature performance of transimpedance amplifiers built using OPA827. The results were analyzed with a noise model describing the measurement system. We found that it is more advantageous to use a cryogenic transimpedance amplifier when the impedance of the device under test is high as in the case for most quantum devices. | Cryogenic transimpedance amplifier based on a commercial operational amplifier | 10.1007/s40042-023-00917-4 |
2023-10-01 | To solve the cryogenic temperature problems faced by all-concrete liquefied natural gas (ACLNG) storage tanks during servicing, a low temperature resistant and high strength concrete (LHC) was designed from the perspectives of reducing water-binder ratio, removing coarse aggregates, optimizing composite mineral admixture and utilizing steel fibers. The variation laws of compressive and tensile strength, elastic modulus and Poisson’s ratio for C60 concrete and LHC were compared and analyzed under the temperatures from 10 to −165 °C through uniaxial compression and tensile tests. The rapid freezing method was adopted to analyze the evolution process of mass and relative dynamic elastic modulus loss rates for C60 and LHC in 0–300 freeze-thaw cycles. The gas permeability test was carried out, and the laws of gas permeability coefficient varied with temperature and cryogenic freeze-thaw cycles were obtained. Then, the grey dynamic model GM (1,1) was used to predict the variation laws of physical and mechanical parameters on the basis of the test data. The test results demonstrate that the compressive strength, elastic modulus and Poisson’s ratio for both C60 and LHC increase significantly from 10 to −165 °C, but the specific variation laws are different, and there is a phenomenon that some parameters decrease after reaching a critical temperature range for C60. The uniaxial tensile strength increases first and then decreases as temperature decreases, and finally increases slightly at −165 °C for both C60 and LHC. The mass and relative dynamic elastic modulus loss rates of LHC are much lower than that of C60 under different freeze-thaw cycles. The gas permeability coefficient of C60 declines gradually with the drop of temperature, and increases gradually with the number of freeze-thaw cycles while the gas permeability coefficient of LHC basically remains stable and is much lower than that of C60. Therefore, such a conclusion can be drawn that LHC has better properties at cryogenic temperature. On the premise of providing consistent functional mode, GM (1,1) can predict the test data with high accuracy, which well reflects the variation laws of relevant parameters. | Research and Prediction on the Properties of Concrete at Cryogenic Temperature Based on Gray Theory | 10.1007/s11595-023-2794-1 |
2023-10-01 | This study aims to investigate the impact of various input variables in electrical discharge machining (EDM) on specific responses, including surface crack length (SCL) and surface roughness (SR). The variables under scrutiny are the electrical conductivity of the workpiece tool, pulse-on time, gap voltage, pulse-off time, and gap current. The study focuses on generating a mesoscale square blind hole in both cryo-treated and untreated workpieces using electrolytic oxygen-free copper. Experimental design and statistical software were employed to facilitate the analysis, following Taguchi’s L18 (61 × 34) orthogonal array. Through heat map, it was determined that pulse on time, pulse off time, and gap voltage significantly influence surface roughness. On the other hand, workpiece electrical conductivity, gap current, gap voltage, and pulse on time were found to impact surface crack length. It can be seen from the study that the formation of surface cracks exhibited a decreasing trend at the initial level of conductivity of the workpiece, while SCL increased as the WEC was raised. Additionally, lower values of gap current were associated with greater crack length, whereas increasing the gap current reduced crack length. Furthermore, an increase in gap voltage corresponded to an increase in crack length, whereas crack length decreased with an increase in pulse on time. Machine learning regression methods employed in the study could predict surface roughness and surface crack length values with R -squared values more than 0.90. | Surface roughness and surface crack length prediction using supervised machine learning–based approach of electrical discharge machining of deep cryogenically treated NiTi, NiCu, and BeCu alloys | 10.1007/s00170-023-12269-1 |
2023-10-01 | In this work, the impacts of shallow cryogenic (−40 °C) and natural ageing treatments on the precipitation of the second phases in a 7xxx alloy were investigated. Using the differential scanning calorimetry (DSC) analysis technique, transformation temperatures of the phases both in standard natural aged and naturally aged after cryogenic treatment were determined. As a result of the analyses made, the activation energies of the precipitates formed in the material were calculated with the Kissinger, Takhor and Augis-Bennett equations and their effects on diffusion were considered. With DSC analysis, nucleation characteristics of the η ′ phase (MgZn2) were determined by the Avrami parameter from the Ozawa equation. Also, features and distributions of different types of precipitates were analysed by means of scanning electron microscopy (SEM), energy-dispersive X-ray spectrometry (EDS) and X-ray diffraction (XRD) techniques, respectively. Particularly, during the cryogenic and natural ageing processes, dislocation densities, strain values of the planes, texture coefficients and so subsequent after effects on the crystal structure were assessed. It was anticipated that excess dislocations generated during sub-zero treatment preferably settled on suitable planes to subside the strain energy. Finally, it was noticed that compared to natural aged samples, application of the cryogenic treatment before ageing upsurged the hardness of the material on the average by15%. This was possibly because of the η′ precipitates nucleated mainly on dislocations. Graphical abstract | A survey of the effect of cryogenic treatment and natural ageing on structural changes and second-phase precipitation in Al–Zn–Mg–Cu alloy | 10.1007/s10973-023-12414-8 |
2023-10-01 | The present work had evaluated the effect of cryogenic treatment (233 K) on the degradation of polymeric biomaterial using a numerical model. The study on effect of cryogenic temperature on mechanical properties of cell-seeded biomaterials is very limited. However, no study had reported material degradation evaluation. Different structures of silk-fibroin-poly-electrolyte complex (SFPEC) scaffolds had been designed by varying hole distance and hole diameter, with reference to existing literature. The size of scaffolds were maintained at 5 $$\times$$ × 5 mm^2. Current study evaluates the effect of cryogenic temperature on mechanical properties (corelated to degradation) of scaffold. Six parameters related to scaffold degradation: heat transfer, deformation gradient, stress, strain, strain tensor, and displacement gradient were analyzed for three different cooling rates (− 5 K/min, − 2 K/min, and − 1 K/min). Scaffold degradation had been evaluated in the presence of water and four different concentrations of cryoprotectant solution. Heat distribution at various points (points_base, point_wall and point_core) on the region of interest (ROI) was found similar for different cooling rates of the system. Thermal stress was found developing proportional to cooling rate, which leads to minimal variation in thermal stress over time. Strain tensor was found gradually decreasing due to attenuating response of deformation gradient. In addition to that, dipping down of cryogenic temperature had prohibited the movement of molecules in the crystalline structure which had restricting the displacement gradient. It was found that uniform distribution of desired heat at different cooling rates has the ability to minimize the responses of other scaffold degradation parameters. It was found that the rates of change in stress, strain, and strain tensor were minimal at different concentrations of cryoprotectant. The present study had predicted the degradation behavior of PEC scaffold under cryogenic temperature on the basis of explicit mechanical properties. Graphical Abstract | Evaluation of heat transfer in porous scaffolds under cryogenic treatment: a numerical study | 10.1007/s11517-023-02844-9 |
2023-10-01 | Austenitic S30408 stainless steel exhibits good low-temperature resistance and good welding performance. This steel is often used in liquefied natural gas stainless steel storage tanks. During the construction process, the tank wall is primarily connected by butt weld joints. Because welded joints are easily affected by temperature, low-temperature weld cracking can reduce the safety of structures. To study the cryogenic mechanical properties of austenitic S30408 stainless steel welded joints at low temperatures, the low-temperature mechanical properties of austenitic S30408 stainless steel base metal and welded joint components were studied by tensile tests from − 60 to 20 °C and scanning electron microscopy analysis of fractures at various temperatures. The results show that when the temperature decreases, the stress–strain curve of base metal components changes from a power function type to an inverted "s" type; in addition, secondary hardening occurs. The yield strength and tensile strength of the welded joint and base metal increased with decreasing temperature, and the elongation and reduction of area decreased. The plastic deformation capacity of the welded joint was significantly lower than that of the base metal, and there were obvious inclusions in the microstructure. | Experimental Analysis of the Mechanical Properties of Austenitic S30408 Stainless Steel Welded Joints at Low Temperatures | 10.1007/s13296-023-00765-9 |
2023-10-01 | Based on experimental and theoretical results, the magnetic properties, magnetic phase transitions, and magnetocaloric effect (MCE) of TmNi_2Si_2 were studied. In this study, we confirmed that unstable antiferromagnetic interaction underwent a field-induced phase transition from meta-magnetic to ferromagnetic under magnetic fields exceeding 0.2 T in TmNi_2Si_2. Moreover, a large reversible cryogenic MCE was observed. The maximum magnetic entropy change (−ΔS_M^max) and refrigeration capacity were found to be 15.4 J kg^−1 K^−1 and 68.0 J kg^−1, respectively, when changing the magnetic field from 0 to 2 T. The large reversible MCE observed under the low magnetic field change indicates the potential application of TmNi_2Si_2 in cryogenic magnetic refrigerators. 基于实验和理论结果, 我们对TmNi_2Si_2化合物的磁性, 磁相变和磁热效应进行了研究. TmNi_2Si_2化合物被证实存在不稳定的反铁磁相互作用, 并在超过0.2 T的外加磁场下发生从反铁磁到铁磁的场驱动变磁转变. 此外, 大的可逆低温磁热效应也被观察到. 在0–2 T的变化磁场下, 最大磁熵变和制冷量分别为15.4 J kg^−1 K^−1和68.0 J kg^−1. 因此, 低磁场下大的可逆磁热效应表明TmNi_2Si_2化合物在低温磁制冷机中具有潜在的应用前景. | Unstable antiferromagnetism and large reversible magnetocaloric effect in TmNi_2Si_2 | 10.1007/s40843-023-2539-3 |
2023-10-01 | Post-combustion carbon dioxide (CO_2) capture is considered a potential method to mitigate CO_2 emissions from fossil fuels burned in power plants. In recent years, combining two different methods of post-combustion CO_2 capture such as membrane and cryogenic distillation has been explored for availing the advantages of each method. This study focuses on the optimization of membranes for developing the membrane–cryogenic distillation process. For this purpose, a process flow sheet is developed, and simulation with model components such as compressor, heat exchanger, turbo expander, and distillation column is carried out using Aspen Plus. A membrane model is developed using in-house MATLAB code, and optimization is done to achieve higher concentration and recovery of CO_2 using the MOJAYA algorithm. The membrane model is coupled to Aspen Plus through component object model (COM) technology. In this investigation, a hollow fiber membrane is considered. The optimized specifications of membrane modules are length, number of hollow fibers, feed pressure, and permeate pressure which are 0.3 m, 100,000, 5.76 bar, and 0.1 bar, respectively. This analysis results in the purity and recovery of the process of 99.8 and 90%, respectively, and an energy penalty of around 1.74 MJ/kg of CO_2. A comparison of other processes available in the literature reveals that the current study renders maximum purity and recovery with a minimum energy penalty. | Multiobjective optimization of membrane in hybrid cryogenic CO_2 separation process for coal-fired power plants | 10.1007/s11356-023-29945-0 |
2023-10-01 | Under conventional temperature regimes, optical fiber sensors (OFS) have been extensively utilized for real-time monitoring of strain and temperature responses in transportation, energy, and civil engineering structures. However, in low-temperature environments, OFS applications confront challenges such as poor adhesion, diminished sensitivity, weak signal transmission, and complex compensation requirements. Therefore, it is crucial to conduct in-depth research on the high-precision calibration characteristics of strain and temperature in cryogenic conditions. In this study, we propose an enhanced calibration technique for fiber Bragg grating (FBG) strain/temperature sensitivity, covering a low-temperature range of 77–296 K. Employing a custom-designed low-temperature testing apparatus, we calibrated the thermo-optic coefficients, temperature, and strain sensitivity coefficients. Subsequently, this improved method was applied to measure the coefficient of thermal expansion of various materials. The results confirm the accuracy of the proposed method and present the strain/temperature measurement properties of FBG. This research provides guidance for the precise use of FBG in low-temperature environments. | Optimized Cryogenic FBG Sensitivity Coefficient Calibration for High-Precision Thermal Expansion Measurements | 10.1007/s10909-023-02980-4 |
2023-10-01 | Low thermal conductivity of titanium alloy tends to increase the cutting temperature and tool wear, which can thereafter adversely affect the integrity of machined surfaces. Therefore, EBSD was performed dry and various cryogenic chilling procedures to characterize the microstructure and mechanical properties of the drilled surfaces on the titanium alloy. The heat-sink channel was used during drilling for effective heat dissipation by flowing the cryogenic coolant through it. Dry and heat-sink-based cryogenic cooling was used for drilling trials, with cutting speeds of 65 m/min and 95 m/min, feed rates of 0.1 mm/rev and 0.2 mm/rev, and cryogenic temperatures of − 25 °C, − 50 °C and − 75 °C. A whole indexing of the grain structure was observed under the drilling edge using cryogenic cooling with a heat-sink. The cryogenic cooling also gave the smallest machining affected zone of 6 μm, and the strain in the grain of 0.4 and 1.1 at the feed rate of 0.1 mm/rev and 0.2 mm/rev, respectively, resulted in the uppermost standardized image quality value which denotes the highest defect-free microstructure on the drilled surfaces, the least value of low-angle boundaries of grains and kernel average misorientation and a higher value of nano-hardness of 8 GPa as compared to dry drilling. | Microstructural Analysis and Integrity of Drilling Surfaces on Titanium Alloy (Ti–6Al–4V) Using Heat-Sink-Based Cryogenic Cooling | 10.1007/s13632-023-00999-3 |
2023-10-01 | 金属玻璃存在纳米尺度空间 不均匀性. 然而外场激发下, 金属玻璃的结构/力学不. 均匀性演变及其与物性之间的关联尚不明确. 本文通 过纳米压痕技术, 原子力显微镜及高分辨透射电镜表 征手段，探究了低温热循环对纳米结构金属玻璃薄膜 力学/结构不均匀性, 纳米蠕变行为及光学性能的影响. 研究表明低温热循环改变了硬度, 模量, 能量耗散的 分布趋势, 力学不均匀性先增加后减, 基于Maxwell–Voigt 模型. 低温热循环容易激活软区长弛豫时间的缺 陷. 对硬区缺陷影响较小; 瞬态蠕变向稳态蠕变转变 的时间延长. 由于Cu 和Ni 元素的富集, 15 次低温热 循环后的样品反射率提高. 这项工作为金属玻璃力学/ 结构不均匀性特征及其对纳米蠕变行为及光学性能的演化提供了新的见解, 对未来高性能纳米结构金属玻 璃薄膜新材料的开发具有重要的指导意义. Metallic glasses are spatially heterogeneous at the nanometer scale. However, the effects of external excitation on their structural and mechanical heterogeneity and the correlation to their properties are still unresolved. Nanoindentation, atomic force microscopy (AFM) and high-resolution transmission electron microscopy (HRTEM) were carried out to explore the effects of cryogenic thermal cycling (CTC) on mechanical/structural heterogeneity, nanoscale creep deformation and optical properties of nanostructured metallic glass thin films (MGTFs). The results indicate that CTC treatment alters the distribution fluctuations of hardness/modulus and energy dissipation and results in an increase-then-decrease variation in mechanical heterogeneity. By applying Maxwell–Voigt model, it can be shown that CTC treatment results in a remarkable activation of more defects with longer relaxation time in soft regions but has only a slight effect on defects in hard regions. In addition, CTC treatment increases the transition time from primary-state stage to steady-state stage during creep deformation. The enhanced optical reflectivity of the MGTFs after 15 thermal cycles can be attributed to increased aggregation of Cu and Ni elements. The results of this study shed new light on understanding mechanical/structural heterogeneity and its influence on nanoscale creep deformation and optical characteristics of nanostructured MGTFs, and facilitate the design of high-performance nanostructured MGTFs. Graphical abstract | Tailoring mechanical heterogeneity, nanoscale creep deformation and optical properties of nanostructured Zr-based metallic glass | 10.1007/s12598-023-02440-8 |
2023-10-01 | Material removal processes, including turning and milling, are still commonly used operations for manufacturing most of mechanical components in modern industry. Apart from the cutting parameters, the cooling method has the great impact on the technological effects and, above all, on the environmental friendliness of production. In this study, multi-response optimization on the effect of wet and cryogenic machining is performed during the turning of AISI D2 steel samples. Spindle speeds, feed rates, depths of cut, and cutting fluid types varied in a Taguchi mixed design L16 orthogonal array. Statistics, such as an analysis of variance (ANOVA) and a regression model, were applied to the obtained data on the metal removal rate and surface roughness. By employing a grey relational analysis, the best cutting factors for a set of several responses were determined. Among the many factors influencing the rate at which material is removed, analysis of variance revealed that the feed rate was the most influential factor (46.67%), followed by spindle speed (46.65%). Analysis of the factors influencing surface roughness pointed to the feed, cutting condition, and spindle speed as the most essential at 56.66%, 26.04%, and 11.7%, respectively. ANOVA of grey relational analysis shows that speed followed by cutting conditions is the most predominant factor, with a percentage contribution of 71.9% and 14.14%, respectively. From grey relational analysis, a level setting of 4-4-1-2 was identified as the best possible combination of multi-response process parameters. A close agreement is observed between the predicted value of GRG 0.7927 and the experimental validation value of GRG 0.8031. Moreover, the validation test reveals that the percentage errors in estimating material removal rate, surface roughness, and GRG, respectively, are 4.33%, 9.09%, and 1.29%, from predicted values. A study on metallographic observations revealed that parts after wet machining have more tool marks on the treated surface than parts after cryogenic machining. | Multi-response optimization on the effect of wet and eco-friendly cryogenic turning of D2 steel using Taguchi-based grey relational analysis | 10.1007/s00170-023-12182-7 |
2023-09-22 | Fast-charging lithium-ion batteries are highly required, especially in reducing the mileage anxiety of the widespread electric vehicles. One of the biggest bottlenecks lies in the sluggish kinetics of the Li^+ intercalation into the graphite anode; slow intercalation will lead to lithium metal plating, severe side reactions, and safety concerns. The premise to solve these problems is to fully understand the reaction pathways and rate-determining steps of graphite during fast Li^+ intercalation. Herein, we compare the Li^+ diffusion through the graphite particle, interface, and electrode, uncover the structure of the lithiated graphite at high current densities, and correlate them with the reaction kinetics and electrochemical performances. It is found that the rate-determining steps are highly dependent on the particle size, interphase property, and electrode configuration. Insufficient Li^+ diffusion leads to high polarization, incomplete intercalation, and the coexistence of several staging structures. Interfacial Li^+ diffusion and electrode transportation are the main rate-determining steps if the particle size is less than 10 μm. The former is highly dependent on the electrolyte chemistry and can be enhanced by constructing a fluorinated interphase. Our findings enrich the understanding of the graphite structural evolution during rapid Li^+ intercalation, decipher the bottleneck for the sluggish reaction kinetics, and provide strategic guidelines to boost the fast-charging performance of graphite anode. The microstructure of graphite upon rapid Li^+ intercalation is a mixture of differently staging structures in the macroscopic and microscopic scales due to the incomplete and inhomogeneous intercalation reactions hindered by the sluggish reaction kinetics. The Li^+ interface diffusion dominates the reaction kinetics at high rates in thin graphite electrode, while Li^+ diffusion through the electrode cannot to be neglected for thick graphite electrode. | Kinetic Limits of Graphite Anode for Fast-Charging Lithium-Ion Batteries | 10.1007/s40820-023-01183-6 |
2023-09-01 | Considering the lower structural stiffness of titanium alloy thin-walled parts, the machining deformation defects were inevitable. In this paper, the theory and a series of experiments of liquid nitrogen (LN_2) cooled titanium alloy milling were executed in details. Based on cantilever sheet, a deflection calculation model of thin-walled parts subjected to milling force load was established considering cooling temperature. Compared with the conventional cooling milling strategy, the effects of LN_2 jet impingement on the deformation of milling area were analyzed. The results showed the deformation is related to the milling force, elastic modulus, and the milling point coordinates, and the cooling temperature has an effect on the milling deformation. At cryogenic, the milling force can only be increased by 10% compared with conventional cooling, but nearly 30% for the elastic modulus, as well as following the decreased deflection. At − 130 °C, the brittle chip fracture can be achieved, and the burr phenomenon on the machining surface is improved as well as the machining error. And the deformation of the milling area is decreased significantly. Meanwhile, the high speed milling can reduce the load of the free cutting parts. In addition, LN_2 can be achieved full boiling at the large flow of 35.5 L/h, and can quickly reduce the cooling temperature of cutting area and improve the heat transfer efficiency itself. The high milling speed and larger LN_2 flow can further improve the deformation defects of thin-walled parts. The cryogenic cooling strategy can change the chip breaking form, reduce the flexural deformation, increase the effective milling speed, and improve the milling system stiffness and the cutting heat transfer efficiency. They are the main reasons for the improvement of the deformation defects in thin-walled parts milling. | Milling performance of cryogenic cooled titanium alloy thin-walled parts based on cantilever sheet | 10.1007/s00170-023-11987-w |
2023-09-01 | A comparative study of the structure, wear resistance and mechanical properties of tool steel AISI D2 (Kh12MF) after traditional and alternative heat treatments is performed. The traditional treatment consists of vacuum furnace quenching followed by triple tempering and the alternative treatment includes deep cryogenic treatment followed by nitriding in a tank with molten salt. It is shown that the alternative version changes the morphology of secondary carbides within the steel structure and increases fracture toughness without reducing core hardness. | Nitriding of Steel AISI D2 After Deep Cryogenic Treatment | 10.1007/s11041-023-00927-w |
2023-09-01 | SiC particle-based aluminum matrix (SiCp/Al 20%) is characterized by poor surface quality, high cutting forces, and accelerated tool wear during machining. Environmentally friendly cooling/lubrication (CO_2 snow, MQL) can advance the machinability of such composites even at high material removal rates. In this experimental study, milling of SiCp/Al was performed by implementing MQL and CO_2 at different cutting speeds and feed per tooth and compared the effect of these lubri-cooling against dry cutting. The experimental results showed the minimum cutting forces, surface roughness, and tool life under MQL followed by CO_2 and dry cutting. The microscopic analysis depicted adhesion and abrasion as prevalent wear mechanisms. The EDS analysis (line, point, mapping) revealed relatively less adhesion of aluminum (Al) and silicon (Si) chemical elements under cryogenic compared to dry cutting on tool major cutting edge. Besides, the chip analysis under MQL machining showed discontinuous and serrated-type chips. | Tribological and machining characteristics of milling SiCp/Al MMC composites under sustainable cooling conditions | 10.1007/s00170-023-12083-9 |
2023-09-01 | 为寻求一种新型深冷复合热处理工艺方法, 借助光学显微镜 (OM), 扫插电子显微镜(SEM)、透射电子显微镜 (TEM), 电子背散射衍射 (EBSD), 拉伸试验等测试手段, 结合image pro plus 数据统计分析, 研究了深冷、 固溶、时效复合处理对压铸铝合金合金微观组织和力学性能的影响。结果表明：与T6 热处理相比, 深冷 (‒196 °C, 12 h) + 固溶 (476 °C, 22 min) + 时效 (159 °C, 403 min) 复合热处理能够显著提升压铸铝合金的力学性能, 抗拉强度由224.3 提升到249.5 MPa, 提高了11.2%, 硬度由HV 110.5 提升到HV 124.6, 提高了12.8%, 延伸 率由6.28%提升到7.72%, 提高了22.9%。经深冷复合处理工艺后, 合金的α-Al 相得到显著细化, Si 相趋于椭 圆状或颗粒状, 含铁相尖端变得圆整, 对提高合金的力学性能和组织的稳定性起到关键作用。 To develop a new compound heat treatment process for improving the mechanical properties of die-cast Al alloys, this study investigated the effects of cryogenic, solution and aging compound treatment on the microstructure and mechanical properties of die-cast Al alloys. The characterization methods used were optical microscopy (OM), scanning electron microscopy (SEM), transmission electron microscopy (TEM), electron backscatter diffraction (EBSD), and tensile tests; and the Image Pro Plus software was used for statistical analysis. The results indicated that compared with T6 heat treatment, the compound heat treatment process consisting of cryogenic treatment (−196 °C for 12 h), solid solution treatment (476 °C for 22 min), and aging (159 °C for 403 min) significantly enhanced the mechanical properties of the die-cast Al alloys. For instance, the tensile strength increased from 224.3 to 249.5 MPa; the hardness increased from HV 110.5 to HV 124.6, and the elongation increased from 6.28% to 7.72%, which in relative terms corresponds to 11.2%, 12.8% and 22.9%, respectively. The compound heat treatment process of the alloy led to significant refinement of its α-Al phases. In addition, Si phases tended to be more ellipsoidal or granular, while the tips of Fe-containing phases became rounded, which played a key role in enhancing the mechanical properties and microstructure stability of the alloys. Graphical abstract | Mechanism of cryogenic, solid solution and aging compound heat treatment of die-cast Al alloys considering microstructure variation | 10.1007/s12598-023-02341-w |
2023-09-01 | (Zr_0.6336Cu_0.1452Ni_0.1012Al_0.12)_97.4Er_2.6 bulk metallic glass (BMG) was prepared by copper mold suction casting, and the effects of sub- T _g annealing and cryogenic thermal cycle (CTC) treatment on its microstructure and properties were investigated. Although the specimens after annealing and CTC treatment did not have significant changes in the amorphous structure, the treated specimens exhibited excellent compressive plastic strain of 16.44 and 19.08%, representing an enhancement of 22.59 and 42.28% compared with the as-cast specimens. The change in plasticity was closely related to the arrangement of atoms and the content and distribution of the free volume caused by sub- T _g annealing and CTC treatment. The corrosion resistance of the specimen was further optimized after sub- T _g annealing and CTC treatment and gradually increased with the increase of annealing temperature and the CTC times. This work demonstrated that appropriate annealing temperature and CTC conditions could be used as an effective and controllable way to modulate the mechanical properties of BMGs. | Rejuvenation and Malleability Enhancement of Zr-Based Metallic Glass by Sub-T_g Annealing and Cryogenic Thermal Cycle Treatment | 10.1007/s11665-022-07723-2 |
2023-09-01 | Polyether ether ketone (PEEK) is often used in the biomedical industry because of its remarkable properties, including high-temperature resistance, superior wear and fatigue resistance, and high tensile strength compared to other thermoplastics. The goal of the current study is to study PEEK thermoplastic biomaterial's grinding operation under various cutting situations. PEEK thermoplastic biomaterial's grindability characteristics were assessed in terms of surface roughness, grinding forces, surface hardness, wheel loading, and analysis of surface morphologies. Since the PEEK biomaterial has lower melting point, and poor heat transfer coefficient, it is highly likely to lodge to the pores of wheel surface as well as adhere to ground workpiece, which could result in increased wheel loading and poor ground surface. Here, two auxiliary cooling and cleaning systems, including compressed air jet and cryogenic $${\mathrm{LN}}_{2}$$ LN 2 cooling system as environmentally friendly fluid, have been employed in the grinding process to clean the wheel surface off of the chips. Besides, the effects of input parameters on PEEK grinding were investigated and analyzed as well. The results demonstrate that when utilizing pressured air, the PEEK biomaterial typically exhibits considerably increased surface roughness, the greatest amount of wheel loading, and significant grinding forces; however, when employing a cryogenic cooling system, these characteristics were minimized to a great extent. Besides, images of the wheel surface obtained after grinding have been processed using digital image processing technique in MATLAB platform to determine the proportion of the wheel loading. | Application of a Cryogenic Cooling System on the Grinding Operation of Polyether Ether Ketone Biomaterial (PEEK) | 10.1007/s13369-022-07497-8 |
2023-09-01 | Purpose In recent years, with the further development of superconducting technology, superconducting devices have been applied in particle accelerators and synchrotron radiation light source devices. As a new type of heat transfer structure, helium cryogenic oscillating heat pipe can be used to balance local hot spots in superconductors and improve heat transfer performance. Methods In this paper, a two- dimensional two-turns helium cryogenic oscillating heat pipe model is established. The flow performance of helium cryogenic oscillating heat pipe was analyzed by CFD simulation. Results and conclusion The results show that the development of flow pattern in the helium cryogenic oscillating heat pipe first forms bubble flow under the heating of the evaporation section, and then gradually forms slug flow and annular flow. The process consists of initial stage, transition stage and running stage. In the running stage, the effective thermal conductivity of COHP oscillates around 15,000 W/(m·K). | Simulation study on thermal performance of two turns helium cryogenic oscillating heat pipe for superconducting accelerator | 10.1007/s41605-023-00403-2 |
2023-09-01 | Abstract Gadolinium oxide nanoparticles were synthesized by the electrophysical method of spark discharge. Their structural features and magnetic and magnetocaloric properties have been comparatively analyzed. According to X-ray diffraction analysis data, the synthesized Gd_2O_3 nanoparticles contain two crystallographic phases, cubic and monoclinic. The magnetic entropy change Δ S _M is determined from the data of magnetic isotherm measurements by the Maxwell relationship. The maximal Δ S _M at a magnetic field change amplitude of 2 T is approximately 17 J/(kg K) and observed at a temperature of 2.5 K. | Structure and Magnetic Properties of Gd_2O_3 Nanoparticles Synthesized by Spark Discharge | 10.1134/S0031918X23601348 |
2023-09-01 | This work is devoted to the development of a procedure for the calculation and experimental determination of the thermophysical characteristics of the stator coils of a generator operating using the phenomenon of high-temperature superconductivity. To realize the conditions close to operational ones, temperature regimes of cooling down the coil from 300 to 78 K with subsequent heating to 300 K were implemented during the experiment. The values of the thermophysical characteristics were calculated from the data of temperature measurements at the internal points of the samples. The paper presents a description of the experimental technique. | Identification of Mathematical Models of Heat Transfer of HTSC Coils. 1. Technical Tools and Experimental Technique | 10.1007/s10891-023-02803-z |
2023-09-01 | In this research, the influences of cryogenically treated stainless steel grade 317 on the eco-friendly near-dry wire-cut electrical discharge machining (NDWEDM) processes have been investigated using the minimum quantity of water mixed with oxygen gas (oxygen mist) dielectric fluid. The stainless steel grade 317 has been applied to make the various biomedical and industrial components due to its high creep strength. The wire wear ratio (WWR) and cutting rate (CR) of NDWEDM are compared using cryogenically treated and untreated work materials by Taguchi’s analysis. The water flow rate, gas pressure, spark current, and pulse width had been considered as process parameters. The microstructure of wire electrode and machined surfaces of treated/untreated materials had been compared by scanning electron microscope (SEM) images. The WWR and CR of cryogenically treated materials in NDWEDM are 20.31% lower and 22.32% higher than untreated materials, respectively. | Cryogenically treated and untreated stainless steel grade 317 in sustainable wire electrical discharge machining process: a comparative study | 10.1007/s11356-022-22843-x |
2023-09-01 | Abstract The transboundary part of the Altai mountains has been investigated. It is established that it is characterized by a set of geomorphological elements due to the altitudinal position, geological structure, neotectonic activity, modern and paleo-climatic conditions, and exogenous relief-forming processes. In the highlands of the Mongolian Altai, landforms associated with the formation, movement, and melting of ice are widespread. The geological activity of glaciers, the work of melt water, and the presence of permafrost give rise to bright forms. The formation of the appearance of mountain landscapes and the transformation of the surface are associated with actively ongoing slope processes: avalanches, mudflows, landslides, and rock falls. It is found that the objects of cryogenic genesis are landforms differing in scale, structure, and location. They include snow–ice and rock–ice formations, solifluction forms, areas with frost mounds (palza), polygonal and structural soils, aufeis, etc. It is concluded that the most representative objects of cryogenic genesis illustrating the geological work of ice are modern glacial complexes, rock glaciers, and rock streams. Glaciers constitute the main element of the high-mountain zone for complex conjugated cryogenic forms. In addition to them, smaller forms stand out, the formation of which is associated with the processes of soil change under the influence of permafrost and gravitational processes. Regularities are observed in the structure and arrangement of the landforms in the alpine zone. On the basis of information from field routes, satellite data interpretation, and the use of GIS capabilities, we have analyzed the distribution of cryogenic landforms. Material is prepared on the basis of working with a digital elevation model. A list (catalog) of natural cryogenic objects of different categories identified within the Altai Tavan Bogd National Park has been compiled. The study confirms that the landforms of the highlands are of interest for further study, the replenishment of the catalog of objects, and the development of thematic tourism. | Cryogenic Landforms of the Altai Highlands (a Case Study of the Tavan Bogd National Park, Western Mongolia) | 10.1134/S1875372823030071 |
2023-08-19 | The aim of this study was to investigate the effect of shallow cryogenic treatment on the mechanical properties and microstructural evolution of a Hadfield steel with a chemical composition of (Fe-12Mn-1.2C). An ingot was produced using casting technique and heat treated by austenitizing at 1050 °C for 1 h followed by rapid quenching to room temperature. Samples were cut from the heat treated ingot and divided into three sets: H (no further treatment), HD (5% deformation), and HDC (cryogenic treatment at −80 °C for 2 h after deformation). Microstructural characterizations were performed using optical microscopy, scanning electron microscopy, and transmission electron microscopy. X-ray diffraction was used to identify formed phases and carbides, as well as determine dislocation density, crystallite size, lattice strain value, and texture coefficient. The relationships between stacking faults and dislocation density were investigated, and the wear rate and friction coefficients of the samples were calculated. The results showed that cryogenic treatment and deformation caused mechanical twinning, transformed austenite into α′(BCT) martensite, changed the form of MC type carbides, and increased the dislocation density by approximately 50%. The stacking faults were more pronounced in the cryogenic treatment samples, and the strain value of planes calculated by XRD analysis was high in cryogenically treated samples. The wear rate of the HDC sample improved by about 20% compared to the H sample. These findings provide important insights into the structural changes of high manganese steels and can contribute to the development of new materials with improved properties. | Evaluation of the Effect of Shallow Cryogenic Treatment on Tribological Properties and Microstructure of High Manganese Steel | 10.1007/s40962-023-01131-5 |
2023-08-01 | The motivation of this work is to explore the merits of fractional calculus for designing IMC that uses higher fractional-order filter and controls processes with significant time delays. It is an established fact that fractional-order filter gives extra tuning parameter for controller design, and Smith predictor is an efficient tool for handling time delays. However, the combinatorial performance of fractional-order and Smith-compensated IMC, especially in case of second-order system with significant process-model mismatch and measurement noise, is the focus of this manuscript. Their performance has been assessed and compared with an optimum PID controller available in the literature designed for similar cases. Simulation has been carried out in three case studies involving a linear transfer function model, a nonlinear CSTR process and a cryogenic distillation process. A comparative analysis of all the controllers has been performed. | Design of fractional-order IMC for nonlinear chemical processes with time delay | 10.1007/s40435-022-01087-0 |
2023-08-01 | Abstract This paper presents the results of a study on the influence of heat treatment, including water quenching, cooling of a quenched alloy in liquid nitrogen, holding in liquid nitrogen, and upgoing quenching (heating in hot mineral oil), and natural or artificial aging on the structure, residual stresses, and anticorrosion properties of a D16 deformed aluminum alloy. The structure is studied by light microscopy, transmission electron microscopy, and X-ray diffraction. Residual stresses are determined by the hole drilling method. The corrosion properties are examined using polarization resistance, zero resistance amperometry, electrochemical impedance spectroscopy, and metallography. | Influence of Upgoing Quenching on Structure and Corrosion Properties of Alloy D16 | 10.1134/S2075113323040305 |
2023-08-01 | The demand for dissimilar joining of steel grades, namely austenitic stainless steels to low-alloy steels, may increase in near future owing to the fact that the storing of LNG is currently becoming a necessity, particularly in Europe, due to the shortage of supply or interruptions in the supply. Therefore, successful dissimilar joining of steel grades using traditional fusion welding techniques in such applications is required. In this study, butt-welded joints of AISI 316L austenitic steel and low-alloy steel plates (containing 9% Ni) of 10 mm thickness were fabricated by gas tungsten arc welding employing a Ni-based filler wire. The microstructure and mechanical properties of the weldment were examined by detailed optical microscopy, extensive micro-hardness measurements, and tensile tests. Further, fracture toughness of the joint at cryogenic temperatures (− 196 °C) was also determined by Charpy impact test. The dissimilar joint exhibited a high tensile strength of 633 MPa, which is higher than that of the lower-strength AISI 316L base plate (about 600 MPa), while its elongation (21%) was much lower due to confined plasticity. The lowest impact energy was displayed by HAZ-F notched specimens, namely about 62.6 J (0.83 J/mm^2). However, it is still reasonably above the minimum impact energy specified for the LNG storage tanks, i.e., 0.75 J/mm^2. | Characterizations of Microstructure and Properties of Dissimilar AISI 316L/9Ni Low-Alloy Cryogenic Steel Joints Fabricated by Gas Tungsten Arc Welding | 10.1007/s11665-022-07601-x |
2023-08-01 | Abstract The Lebedev Physical Institute (LPI) actively develops innovative technologies for creating the HTSC—MAGLEV accelerator for delivering a cryogenic fuel target (CFT) placed in a levitating HTSC-carrier to the ICF chamber for interacting with laser radiation. The LPI approach is based on the phenomenon of HTSC quantum levitation in a gradient magnetic field. Acceleration is provided by a sequence of current-carrying solenoids, and HTSC-carrier levitation occurs due to the use of a magnetic rail, along which the solenoids are placed. A prototype of an elementary block for accelerating an HTSC-carrier is developed and its motion control processes are studied. For this purpose, a special system of operational control of the acceleration block is developed and tested. The HTSC-carrier acceleration up to 1 m/s at the acceleration length L _a = 20 cm is demonstrated using only one pair of matched solenoids. The results obtained are of practical importance in the area of creating noncontact systems for CFT delivery due to constructing a linear magnetic track by connecting one elementary acceleration unit with many others to achieve a required CFT injection rates from 20 to 200 m/s and higher. | On the Acceleration of a Superconducting Carrier of a Cryogenic Fuel Target by a Sequence of Current-Carrying Solenoids | 10.3103/S106833562308002X |
2023-08-01 | Aim Efficient fog water utilization under soil drought conditions is important for improving the water status and growth of forest trees. However, importance of fog water retention for trees during drought is yet to be completely examined. The aim of this study was to examine changes in fog water retention in different organs of Japanese black pine ( Pinus thunbergii ) saplings under well-watered and drought conditions. Methods P. thunbergii saplings were grown under well-watered and drought conditions in a glasshouse for 19 days and exposed to ^2 H-enriched water vapor under a high relative humidity (~ 95%) for 1 h in a growth chamber under a uniform light condition. The exposed trees were harvested 48 h after the fog exposure experiment and the ^2 H concentration of water in current needles, old needles, current branches, old branches, roots, and soil was determined. Results Absorbed fog water was detected in the needles, branches, and roots 48 h after exposure to fog. The amount of water in the current needles, old needles, and current branches contributed by fog water was significantly higher in drought-stressed trees than in well-irrigated trees. Small amount of absorbed fog water was redistributed to the soil, irrespective of soil water conditions. Conclusion We found that larger amount of absorbed fog water was retained in drought-stressed trees than that in well-watered trees, which may improve the water status of plants under drought. Our results also suggest that hydraulic redistribution from the roots to the soil may occur irrespective of soil drought conditions. | Soil drought increases the retention time of plant water in Pinus thunbergii saplings | 10.1007/s11104-023-06053-z |
2023-08-01 | This study investigated the gas tungsten arc (GTA) weldability of a base metal (BM) Fe_60Co_15Ni_15Cr_10 medium-entropy alloy (MEA) by applying CoCrFeMnNi and CrFeMnNiCu fillers. Sound welds without macro defects, such as internal pores or cracks, were obtained. The CoCrFeMnNi-based weld consisted of a face-centered cubic (FCC) structure, whereas the CrFeMnNiCu-based weld comprised (Co, Cr, Fe)-rich phase of FCC1 and a Cu-rich phase of FCC2 with the same FCC structure formed by phase separation. In the CrFeMnNiCu-based weld with a Cu-rich phase, the weld metal (WM) was stronger than that in the CoCrFeMnNi-based weld. The tensile fracture of all specimens occurred in the coarse-grained heat-affected zone (CGHAZ) at 298 K, while the tensile properties of the CrFeMnNiCu-based weld were improved compared to those of the CoCrFeMnNi-based weld, probably because the Cu-rich phase present in WM blocks the movement of dislocations. The WM of all tensile specimens at 77 K exhibited deformation twins, and deformation-induced martensitic transformation occurred in the BM and CGHAZ, showing improved strength and ductility compared to those at 298 K. Graphical Abstract | Enhancement of Hardness and Yield Strength Induced by Cu-Rich Phase and Its Effect at Cryogenic Temperature on Gas Tungsten Arc Welds of Ferrous Medium-Entropy Alloy | 10.1007/s12540-022-01376-5 |
2023-08-01 | Abstract Cryogenic treatment is the process of cooling a material to extremely low temperatures to generate enhanced mechanical and physical properties. The present investigation examines the effect of a deep cryogenic treatment on the enhancement of mechanical properties, such as the wear resistance, the corrosion resistance, the tensile strength, and the impact strength of the plunger material 100Cr6 bearing steel. An improvement in those properties of the deep cryogenically treated samples over the conventionally heat treated ones was found to be 50, 26, 13, and 27%, respectively. This study suggests that the formation of very small carbides dispersed in the tempered martensite structure can be the main reason for the enhancement of certain mechanical properties, along with the retained austenite transformations. | Experimental Investigation of the Effect of Deep Cryogenic Treatment of 100Cr6 Bearing Steel | 10.3103/S1068375523040129 |
2023-08-01 | A new machining method, cryogenic-ultrasonic vibration-assisted milling (CUVAM), is proposed to improve the workability of Inconel 718. This study examined the machining mechanism of CUVAM technology at different machining parameters. The cutting force, chip, tool life, workpiece surface morphology, and surface integrity after conventional machining (CM), cryogenic cooling machining (CCM), and CUVAM were compared. The experimental data showed that cryogenic assistance could effectively improve the machining environment and coefficient of friction (CoF) and improve surface integrity. On the other hand, the cutting force increases after CCM due to the low-temperature brittleness of Inconel 718, but the ultrasonic vibration assistance in CUVAM can suppress the increase in cutting force. CUVAM well combines the advantages of cryogenic assistance and ultrasonic assistance. Compared to CM, the CUVAM method can reduce the cutting force by 36.5% and have a beneficial impact on tool life. The chipping effect was more obvious. Compared to CCM, the surface roughness after CUVAM was reduced by 39.1%. The excellent machinability of the CUVAM method was verified through the combination of experiments and theory, which provides a new method for the high-quality, high-efficiency, and pollution-free machining of Inconel 718. | Machinability study of cryogenic-ultrasonic vibration-assisted milling Inconel 718 alloy | 10.1007/s00170-023-11858-4 |
2023-07-12 | Energy field-assisted machining technology has the potential to overcome the limitations of machining difficult-to-machine metal materials, such as poor machinability, low cutting efficiency, and high energy consumption. High-speed dry milling has emerged as a typical green processing technology due to its high processing efficiency and avoidance of cutting fluids. However, the lack of necessary cooling and lubrication in high-speed dry milling makes it difficult to meet the continuous milling requirements for difficult-to-machine metal materials. The introduction of advanced energy-field-assisted green processing technology can improve the machinability of such metallic materials and achieve efficient precision manufacturing, making it a focus of academic and industrial research. In this review, the characteristics and limitations of high-speed dry milling of difficult-to-machine metal materials, including titanium alloys, nickel-based alloys, and high-strength steel, are systematically explored. The laser energy field, ultrasonic energy field, and cryogenic minimum quantity lubrication energy fields are introduced. By analyzing the effects of changing the energy field and cutting parameters on tool wear, chip morphology, cutting force, temperature, and surface quality of the workpiece during milling, the superiority of energy-field-assisted milling of difficult-to-machine metal materials is demonstrated. Finally, the shortcomings and technical challenges of energy-field-assisted milling are summarized in detail, providing feasible ideas for realizing multi-energy field collaborative green machining of difficult-to-machine metal materials in the future. | Energy field-assisted high-speed dry milling green machining technology for difficult-to-machine metal materials | 10.1007/s11465-022-0744-9 |
2023-07-11 | One of the many intriguing current possibilities for these fibres is the possibility of employing them as a reinforcing component in polymeric structures. This study aims to evaluate the compatibility of bamboo fibre and olive tree leaf powder (OTL) as fillers in epoxy composites throughout a variety of cryogenic exposure lengths (such as 15 min, 30 min, and 60 min). The primary and hybrid composites were produced by compression moulding, with total fibre loadings of 30 weight percent and 3, 6, and 10 weight percent, respectively. The composites were subjected to tensile, bending, impact, and dynamic mechanical analysis (DMA) after production in order to characterise them. An investigation of the morphological analysis of the fractured composites was conducted using a scanning electron microscope (SEM). This study shows that 30-min cryogenic treatments, rather than 15- and 45-min ones, had the best outcomes. It increases in tensile strength by 11.34%, flexural strength by 21.76%, and impact strength by 26.52%. The values for the treated composites are 27.10% and 48.63% higher, respectively, than the tensile and flexural modules. Due to lead compounds’ propensity to intensify the mismatch between the fibre and the resin, prolonged cryo-processing times may produce more severe thermal expansions. OTL and bio-composites composed of bamboo interact poorly, which makes them more harmful. The DMA results showed that hybrid composites outperformed primary materials with superior storage moduli, lower loss moduli, and lower damping factors. | Investigation of mechanical and dynamic mechanical analysis of bamboo/olive tree leaves powder-based hybrid composites under cryogenic conditions | 10.1007/s13399-023-04591-1 |
2023-07-01 | In order to improve the microstructure of AZ31 magnesium alloy sheets and enhance their comprehensive mechanical properties, the effects of cryogenic treatment on the microstructure and mechanical properties after hot-rolled AZ31 magnesium alloy were investigated in this paper by combining different rolling reduction with cryogenic treatment. The results show that fine dynamic recrystallization grains appear at the original grain boundaries, and the grain becomes fine and uniform after rolling and deformation. After cryogenic treatment of the hot-rolled sheets, the grains are further significantly refined, the size tends to be homogeneous, the second phase is precipitated along the grain boundaries, and a small amount of twins are produced. In addition, after 20-min cryogenic treatment, the plasticity of the rolled sheets with 30% reduction was greatly improved, and the elongation at break was up to 14.2%, which was 55% higher than that of the original sheet; its hardness and tensile strength were increased from 64.4 HV and 230 MPa of the original sheet to 76.6 HV and 286 MPa, respectively, which shows that the cryogenic treatment of the hot-rolled sheets could effectively improve mechanical properties. This study provides some theoretical guidance and technical support for the processing and manufacturing of high-performance AZ31 magnesium alloy sheets, which has important academic significance and engineering value. | Effects of Rolling-Cryogenic Process on Microstructure and Mechanical Properties of AZ31 Magnesium Alloy Sheets | 10.1007/s11665-022-07559-w |
2023-07-01 | Cryogenic micro-abrasive air-jet machining (CAJM) is a promising future processing technology based on traditional blasting technology. Channel profile is one of the most important indexes to evaluate the performance of PDMS micro-channel. The single-factor experiment of CAJM of PDMS micro-channel was conducted to explore the influence of machining speed, machining pressure, machining angle, and machining distance on channel profile. The BP neural network prediction model of depth-to-width aspect ratio of micro-channel width and depth was established to carry out virtual orthogonal experiment that was applied to explore the limits of the processing capability. The results show that when machining angle is 75° and 90°, the liquid nitrogen jet will promote the discharge of abrasives and chips, and inhibit the secondary machining of the rebound abrasive. The prediction errors of depth-to-width aspect ratio is -4.6%. The maximum depth-to-width aspect ratio obtained by the self-built experimental device was r = 1.938. | Generation of micro-channel on PDMS substrate by cryogenic micro-abrasive air-jet machining | 10.1007/s00170-023-11719-0 |
2023-07-01 | Surface quality governs the physical, mechanical, tribological, physio-chemical, and biological properties of materials. Considering the excellent mechanical characteristics of Inconel 617 and the nature of its intended applications, electric discharge machining is generally engaged. However, there is still a need to uplift the surface quality of machined parts to improve their working life and performance. Therefore, this study revealed the potential of deep cryogenically treated (DCT) electrodes under dielectrics modified with span and tween in the said context using a full factorial experimental design. Experimental findings are deeply investigated by employing 3D surface profilometry, scanning electron, and optical microscopy. Cryogenically treated electrode(s) have demonstrated a better surface quality in comparison to the non-treated electrodes, such as DCT Cu has provided a 25.5% lower roughness value than non-treated Cu. Referring to the role of additives, there exists a reduction of 32.5% in roughness when DCT brass is used instead of typical brass using a mixture of span-20 (S-20) and kerosene as a dielectric. The surface finish given by the cryogenically treated brass is 18.99% better when compared to the average value given by all cryogenically treated electrodes considered in this study. It has also been revealed that tween-based dielectrics gave 83% better surface finish than span-based dielectrics with DCT electrodes. | Surface quality investigation in surfactant-based EDM of Inconel 617 using deep cryogenically treated electrodes | 10.1007/s00170-023-11588-7 |
2023-07-01 | Through cryogenic treatment and electrolytic passivation treatment of M2 high-speed steel (HSS), the effect of electrolytic passivation process parameters on the life of M2 HSS taps and the combined effect of cryogenic treatment and electrolytic passivation treatment on the wear resistance of the M2 HSS were investigated by using a scanning electron microscope (SEM) and energy-dispersive spectrometer (EDS). The results show that the life of M2 HSS tap after electrolytic passivation treatment increases most significantly under the theoretical edge radius; the functional relationship between the charge consumption (y) and the tap edge radius ( x ) is as follows: y = 8.135 x − 48.842. The wear resistance of the sample after cryogenic and electrolytic passivation treatment is the highest, which is 1.52 times higher than those of the traditional heat treatment sample. This is due to the increase of the number of carbides on the surface of the specimens after cryogenic treatment; the distribution and size of carbides are relatively uniform; the average size of carbides is reduced by 60.4%. There is a carbon layer on the surface of the sample after passivation, which can effectively improve the wear condition. The size and number of carbides in the surface layer of the sample remain unchanged after passivation treatment, indicating that cryogenic treatment plays a key role in the performance of the material. | Effect of cryogenic and electrolytic passivation treatment on wear resistance of M2 high-speed steel | 10.1007/s00170-023-11639-z |
2023-07-01 | As the global market for small satellites grows, the demand for small launch vehicles rises as well. In addition, the accelerated technological development of battery and motor have drawn attention to the electric pump cycle for small launch vehicles which utilizes electric motor and battery packs to drive a pump. In this study, a practical design of an electric pump cycle for a 5400 N-class rocket engine is proposed. First, the electric pump with very low specific speed was designed due to limited rotational speed of a commercial motor for cost-effective system. Second, to determine the appropriate discharge angle for very low specific speed pump, two impellers with different discharge angle were designed and verified by numerical and experimental methods. Type A impeller with discharge angle of 10° focusses on achieving high efficiency, while type B impeller with discharge angle of 33° has general geometry. The hydraulic and suction performance of the two impellers was first compared in a cold-water performance test. The hydraulic efficiency of type A impeller was 52.53% and higher than that of type B impeller, 43.28%. Furthermore, type A impeller had higher suction performance than type B impeller; the critical cavitation number of type A impeller was more than 0.07 lower than that of type B impeller. Moreover, the operation of the electric pump under cryogenic environment was verified by performing cryogenic performance tests using liquid nitrogen as simulant. | Design and Verification of Electric Pump for Small LOX/Methane Rocket Engine | 10.1007/s42405-022-00561-5 |
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