bluuebunny/crossref_metadata_2025 huggingface dataset:
Crop Weather Interaction in Potato in South Bengal Plains
Authors: Maji S. , Chakraborty Pramiti K. , Basu S. , Jena Sarika , Poddar Ratneswar , Nath R. , Bandopadhyay P. , Chakraborty P. K.
Published: November 2016

Potato is one of the main staple foods in West Bengal, where it ranks second in production after Uttar Pradesh. There is lots of variation in productivity of the crop. It is due to climatic variability which causes widespread disease infection in potato crop. The shifting of onset and withdrawal of monsoons has also proved to be a barrier in the productivity of the crop. The farmers are habituated to plant the crop within 15th of November; however this is being disrupted because of the shifting of withdrawal of monsoons. Potato is a thermo sensitive crop. The crop growth rate of potato is significantly affected by cumulative maximum and minimum temperatures. Leaf area index significantly decreased with the increase in cumulative maximum and minimum temperatures. Rainfall and relative humidity are two crucial factors that determine the incidence of late blight in potato, the most devastating disease in Bengal. Rainfall increased productivity by lowering soil temperature and reducing hydrolysis of starch respiratory losses from tubers.
Impact of Climate Change on Potato Production in India
Authors: Jatav M. K. , Dua V. K. , Govindakrishnan P. M. , Sharma R. P.
Published: November 2016

Potato is a temperate crop and higher day temperatures cause some areas to less suitable for potato production due to lower tuber yields and its quality. Tuber growth and yield can be severely reduced by temperature fluctuations outside 5-30 °C. The rate of warming in last 50 years is double than that for the last century. Increase in temperature and atmospheric CO2 are interlinked occurring simultaneously under future climate change and global warming scenarios. If CO2 is elevated to 550 ppm the temperature rise is likely to be 3 ºC with decline in potato production by 13.72% in the year 2050. The changing climate will affect the potato production adversely due to drought, salinity, frost, flooding, erratic unseasonal rains etc. It may reduce seed tuber production, impact storage facility and potato processing industries. Therefore, the quantification of regional vulnerability and impact assessment is very important for the development of early warning on disease forecasting systems, breeding of short duration and heat, drought, salinity tolerant and disease resistant cultivars.
Improved Agronomic Practices and Input Use Efficiency for Potato Production under Changing Climate
Authors: Mukherjee Dhiman
Published: November 2016

In the emerging global economic order in which agricultural crop production is witnessing a rapid transition to agricultural commodity production, potato is appearing as an important crop, poised to sustain and diversify food production in this new millennium. Temperature and unpredictable drought are two most important factor affecting world food securities and the catalyst of the great famines of the past. Decreased precipitation could cause reduction of irrigation water availability and increase in evapo-transpiration, leading to severe crop water-stress conditions. Increasing crop productivity in unfavourable environments will require advanced technologies to complement traditional methods which are often unable to prevent yield losses due to environmental stresses. Various crop management practices such as improved nutrient application rate, mulching, raised beds and other improved technology help to raise the productivity. Conservation farming practices play important role to restore soil and enhancing soil health and play important role to combat climate change issue.
Impact of Global Climate Change on Potato Diseases and Strategies for Their Mitigation
Authors: Lal Mehi , Yadav Saurabh , Pant Rajendra Prasad , Dua Vijay Kumar , Singh B. P. , Kaushik Surinder Kumar
Published: November 2016

The quality and quantity of the potatoes produced is directly affected by the climatic factors that prevailed during the crop season. It is also well established that abiotic and biotic stresses cause tremendous losses to the crop. Host plants and their pathogens are prone to various climatic factors like temperature, relative humidity, rainfall and CO2 which are behaving in erratic manner. Phytophthora infestans has adapted itself at higher temperature so there are chances to spread at a larger area. The other potato diseases like early blight, bacterial wilt, soft rot and viral diseases may also behave differently at elevated temperature and high rainfall. Viral diseases of potato are serious threat to potato industry as most of the viruses are transmitted by vectors and vector populations are bound to increase with these changed climatic conditions. Therefore, potato researchers need to simulate these conditions and devise mitigation strategies for sustained potato production.
Influence of Thermo- and HIP Treatments on the Microstructure and Mechanical Properties of IN625 Alloy Parts Produced by Selective Laser Melting: A Comparative Study
Authors: Kreitcberg Alena , Brailovski Vladimir , Turenne Sylvain , Chanal Cyrille , Urlea Victor
Published: November 2016

This study provides a summary of the effect of heat and hot isostatic pressing treatments on the microstructure and mechanical properties of IN625 alloy processed by selective laser melting. IN625 metallographic and tensile testing specimens were additively manufactured in four different orientations and then subjected to stress relief, low solution annealing and hot isostatic pressing treatments. The as-built alloy exhibited the highest tensile strength, the lowest ductility and the highest anisotropy of mechanical properties among all the tested specimens. Heat and hot isostatic pressing treatments provided an improvement in ductility and homogeneity, but at the expense of lower strength characteristics. The results of this study provide some indications for improving the mechanical properties of additively manufactured IN625 alloy components.
Modelling Yield Strength in an A6061 Aluminium Alloy
Authors: Kreyca Johannes , Falahati Ahmad , Kozeschnik Ernst
Published: November 2016

The yield strength of an A6061 Aluminium alloy for different artificial ageing times, strain rates and temperatures is modelled taking into account precipitation, solid solution and dislocation forest strengthening. Precipitation kinetics during artificial aging and the individual strength contributions are simulated with the thermokinetic software package MatCalc. In the present contribution, we introduce the model for the temperature and strain rate dependence of the yield-strength based on thermal activation theory. The experimental work presented here is performed on a Gleeble 1500 thermo-mechanical simulator, where the solution annealed and quenched samples are heat treated to produce materials in various microstructural conditions. We demonstrate that yield strength simulation is a powerful tool to reduce experimental effort and to cut down costs in the process of alloy engineering. This approach consistently represents the yielding behaviour of alloys in a variety of microstructural conditions with respect to the production history of the alloy and the testing conditions, i.e. temperature and strain rate.
Mechanical Properties of Polymer-Based Hybrid Films: Tailoring the Hybrid Interface Using Soft Chemistry
Authors: Mammeri Fayna , Le Bourhis Eric
Published: November 2016

Soft chemistry (chimiedouce) processes allow the design of multifunctional composite coatings tailoring the interfaces between phases. Instrumented indentation has become routinely used to characterize thin systems and allows for getting insight into interface mechanics. The paper illustrates both experimental approaches allowing for the fabrication PMMA based nanocomposites and their characterization employing nanoindentation.
Atomic Layer Deposited Protective Layers
Authors: Leskela Markku , Salmi Emma , Ritala Mikko
Published: November 2016

This paper reviews the use of Atomic Layer Deposition (ALD) in protective coatings. Because of the growth principle ALD allows the deposition of dense conformal films on substrates of different size and shape. Recently, ALD has received increasingly interest in deposition of protective coatings. In protective coatings oxides are the most common materials and especially Al, Ti, and Ta oxides have been applied. The use of nanolaminates enables improving the protection properties. Since ALD films are pinhole-free and often thin they are used to protect against moisture, radiation, out-gassing but not often against corrosion of metals. Very good moisture barriers are obtained with thin ALD oxide layers on polymers and cardboard. This property is also very attractive in encapsulation of OLEDs. In studies of energy technology materials protection of electrodes in Li-ion batteries, fuel cells and supercapacitors by ALD has been reported and significant improvement in the stability has been achieved. Yet another area is protection of silver jewelry from tarnishing by a thin oxide layer. In traditional corrosion protection of metals ALD films have proven to be useful in tailoring of interfaces and sealing of defects in coatings made by other techniques.
Microstructure Evolution of a Directionally Solidified Ternary Eutectic Mo-Si-B Alloy
Authors: Krüger Manja , Hasemann Georg , Kazemi Omid , Halle Thorsten
Published: November 2016

The aim of the present study is to identify the ternary eutectic Mo-Si-B composition to produce directionally solidified materials, which are expected to have excellent high-temperature properties due to the well-defined microstructure. Different alloy compositions in the respective primary solidification areas of the phases were chosen to investigate the microstructural evolution. The results were compared to thermodynamic calculations of the liquidus projection and isopleth phase diagrams using the software FactSageTM. By carrying out these experiments the eutectic point was found to have a nominal composition of Mo-17.5Si-8B (at.%). In the next step, the eutectic alloy was directionally solidified by a zone melting (ZM) process. The evolution of a typical eutectic microstructure due to the growth of lamella-like structures is shown by microstructural investigations. Furthermore, we present a eutectic phase field model for the eutectic Mo-Si-B alloy. The equilibrium interface geometries and interface mobility were calculated using an isotropic model. The results are shown to be in an adequate conformity with the experimental observations.
Boron Effect on Hardenability of High Thickness Forged Steel Materials
Authors: Mengaroni Sabrina , di Nunzio Paolo Emilio , Neri Stefano , Calderini Massimo , Braccesi Claudio , Cianetti Filippo , di Schino Andrea
Published: November 2016

To fulfill the industrial demand of forged steels with high mechanical and microstructural requirements coupled with reduced cost, the possibility to decrease the content of Mo and other elements has been evaluated. In order to do that, the effect of boron addition (up to 30 ppm) on the steel hardenability has been investigated on two steels with different chemical composition at laboratory scale. In particular, the steel chemical composition has been designed in order to make effective the B addition in terms of hardenability. Two 80 kg ingots cast by a vacuum induction melting plant have been hot rolled by a pilot mill. The effect of B addition on hardenability has been evaluated and compared to that of steel for same application but without B. Results show an improvement of hardenability if 30 ppm B are added even if a Mo reduction is performed.
On the Elaboration of Metal-Ceramic Composite Coatings by Laser Cladding
Authors: Mertens Anne , L’Hoest Thibaut , Magnien Julien , Carrus Raoul , Lecomte-Beckers Jacqueline
Published: November 2016

This paper reports on a preliminary investigation into the elaboration, by the additive process known as laser cladding, of composite coatings with a matrix of stainless steel 316L reinforced with varying contents of tungsten (WC) or silicon carbides (SiC) particles. Laser cladding is characterised by ultra-fast solidification and cooling rates, thus giving rise to ultra-fine out-of-equilibrium microstructures and potentially enhanced mechanical properties. Both types of composite coatings – i.e. with SiC or WC ‒ are compared in terms of their microstructures and hardness. Special attention is given to the dissolution of the carbides particles and to interfacial reactions taking place between the particles and the metallic matrix.
Influence of Severe Plastic Deformation on Mechanical Properties of an AA5024 Alloy
Authors: Mogucheva Anna , Yuzbekova Diana , Lebedkina Tatiana , Lebyodkin Mikhail , Kaibyshev Rustam
Published: November 2016

The paper reports on the effect of severe plastic deformation on mechanical properties of an Al-4.57Mg-0.35Mn-0.2Sc-0.09Zr (in wt. pct.) alloy processed by equal channel angular pressing followed by cold rolling (CR). The sheets of the 5024 alloy with coarse grained (CG) structure exhibited a yield stress (YS) near 410 MPa and an ultimate tensile strength (UTS) of 480 MPa, while the YS and UTS of this material with ultrafine-grained (UFG) structure increased to 530 and 560 MPa, respectively. On the other hand, the elongation to failure decreased by a factor of 2 and 4 after CR and CR following ECAP, respectively. It was shown that dislocation strengthening attributed to extensive CR plays a major role in achieving high strength of this alloy. Besides these macroscopic characteristics, jerky flow caused by the Portevin-Le Chatelier (PLC) instability of plastic deformation was examined. The formation of UFG structure results in a transition from mixed type A+B to pure type B PLC serrations. No such effect on the serrations type was observed after CR.
Friction and Wear Properties of αAlB12-NiAl Cermet Prepared by Spark Plasma Sintering
Authors: Murakami Takashi , Inui Haruyuki
Published: November 2016

In this study, αAlB12-20vol% NiAl cermet disk specimens were prepared by spark plasma sintering, and their microstructure, Knoop hardness, fracture toughness, and friction and wear properties were investigated. The αAlB12-20vol% NiAl disk specimens were obtained by spark plasma sintering blended αAlB12 and NiAl powder at 1573 K for 600 seconds. No reaction product phases were observed between the αAlB12 and NiAl phases. The αAlB12-20vol% NiAl disk specimens exhibited friction coefficients lower than 0.2 and specific wear rates as low as 1.3 × 10-6 mm3/Nm when sliding against Si3N4 ball specimens in water. O-rich phases were observed on the worn surfaces of the NiAl and αAlB12-20vol% NiAl disk specimens after sliding against Si3N4 ball specimens in water. The Knoop hardness of the disk specimens was as high as 10 GPa and the fracture toughness was as high as 7 MPa m1/2.
Misorientation Measurement of Individual Grains in Fatigue of Polycrystalline Alloys by Diffraction Contrast Tomography Using Ultrabright Synchrotron Radiation
Authors: Nakai Yoshikazu , Shiozawa Daiki , Nakao Ryota , Asakawa Naoya , Kikuchi Shoichi
Published: November 2016

A three dimensional grain mapping technique for polycrystalline materials, called X-ray diffraction contrast tomography (DCT), was developed at SPring-8, which is the brightest synchrotron radiation facility in Japan. The developed technique was applied to a commercially pure iron and austenitic stainless steel. The shape and location of grains could be determined by DCT using the apparatus in a beam line of SPring-8. To evaluate the dislocation structure in fatigue, the total misorientation of individual grains was measured by DCT. The average value of the total misorientation over one sample was increased with the number of cycles. In a grain, the change of the total misorientation was largest for primary slip plane. For austenitic stainless steel (fcc), the change of the total misorientation in fatigue was larger for planes with larger Schmid factor, while it was not depended on the Schmid factor for commercially pure iron (bcc). This different behavior must come from planer slip in fcc structure and wavy slip in bcc structure.
Influence of Nano Reinforcement Volume Percentage on Fabrication of Surface Nanocomposite by FSP
Authors: Naresh P. , Kumar Adepu , Krishna Kishore M.
Published: November 2016

This work deals with the effect of volume percentage of nanoreinforcement to fabricate nanosurface composite by Friction Stir Processing (FSP) and also studied the role of tool rotational speed and traverse speed to get the defect free condition to fabricate successful surface composite. The material flow pattern, dispersion of the reinforcement particles in the stir zone was examined. From the phase/volume fraction analysis, it was observed that the nanoAl2O3 particles were well dispersed in the stir zone. The results indicate that the better microstructural, mechanical properties were obtained at 1150rpm /15mm/min condition. A significant improvement in microhardness was exhibited by surface nanocomposite as compared to the as - received aluminum.
In Situ Techniques for the Investigation of the Kinetics of Austenitization of Supermartensitic Stainless Steel
Authors: Nießen Frank , Villa Matteo , Apel Daniel , Keßler Olaf , Reich Michael , Hald John , Somers Marcel A.J.
Published: November 2016

The austenitization and inter-critical annealing of X4CrNiMo16-5-1 (1.4418) supermartensitic stainless steel were investigated in-situ with synchrotron X-ray diffraction (XRD), dilatometry and differential scanning calorimetry (DSC) under isochronal heating conditions. Austenitization occurred in two stages: the austenitization started at approx. 600 °C, decelerated at approx. 700 °C at 60 to 75 v.% of transformed austenite, and first resumed after heating for approx. 100 °C. This plateau in the transformation curve was more dominant for faster heating rates. Inter-critical annealing at 675 and 700 °C revealed, that austenite can to a certain extent be stabilized to room-temperature. There was good agreement for the transformation curves yielded by dilatometry and XRD. Some deviation occurred due to the different applied heating principles, different temperature monitoring and the impact of surface martensite formation on the XRD measurement. The applicable temperature range for DSC as well as the close proximity of the Ac1- and the Curie-temperature limited the usage of the technique in the present case.
MgO Implanted in Rat Tibia Bone Marrow is Osteoinductive through the Formation of a Matrix, Containing Hydroxyapatite
Authors: Nygren Håkan , Malmberg Per , Liu Yang
Published: November 2016

Healing of rat tibia after intramedullary implantation of MgO was analysed by Environmental Scanning Electron Microscopy (ESEM) and Energy-Dispersive X-ray spectroscopy (EDX). The results indicated the formation of hydroxyl-apatite (HA) in the entire intramedullary space after 1 week of healing. Then, corroded Mg, MgO and MgCO3 were incubated with DMEM in vitro for 24 h and the surface of the material was analysed by EDX and Time-of-Flight Secondary Ion Mass (ToF-SIMS). The chemical analysis of the Mg corrosion products indicate that HA is formed at the material surface and that MgCO3 was an efficient catalyzer of HA formation
Rapid Measurement of Texture of Metals by Time-of-Flight Neutron Diffraction at iMATERIA and its Applications
Authors: Onuki Yusuke , Hoshikawa Akinori , Sato Shigeo , Ishigaki Toru
Published: November 2016

The authors have developed the texture measurement system at iMATERIA, which is the neutron diffractometers built in Materials and Life Science Experimental Facility (MLF) at J-PARC, Japan. The high flux of the incident beam and Time-Of-Flight method enabled the complete texture measurement within several minutes in case of steels. Since the neutron beam can transmit most of the materials, the measured texture represents the state of whole exposed volume. The multi-histogram analysis also enables to determine phase fractions in a multiphase material as well as the texture of each phase.
Application of Thermo-Calc TCFE7 to High-Alloyed Mottled Cast Iron
Authors: Paar Armin , Elizondo Leonel , Brandner Michael , Trickl Thomas , Sonderegger Bernhard , Beal Coline , Sommitsch Christof
Published: November 2016

The thermodynamic modeling of alloy systems consisting of stable and metastable phases e.g. high-alloyed mottled cast iron can be problematic. Thermodynamic databases are rather well-developed for low, medium and high alloyed steels (e.g. HSS) but the application of those databases is not yet very common for high-alloyed (mottled) cast irons.
The Thermo-Calc software together with the TCFE7 database is used to calculate isopleth and property diagrams, using the CALPHAD method. Additionally Scheil-Gulliver calculations are performed to simulate the effects of microsegregation during solidification. The results from the thermodynamic calculations are compared with measurements on own samples and with literature values. Those measurements include quantitative light-optical analysis, SEM with BSE detector, EDX measurements for the distribution of the alloying elements as well as XRD and DSC measurements.
The investigations show the possibilities which are offered by thermodynamic calculations for high-alloyed mottled cast iron as well as the limitations and the compromises which have to be taken into account when calculating stable and metastable phases existing next to each other.
Experimental Investigation of Welding Parameters on Automatic TIG Welding of Aluminium 5083 Plate
Authors: Praveen V.V. , John T.D. , Peethambaran K.M.
Published: November 2016

To improve the weld quality of AA 5083 plate using AA 5356 filler rod, an automatic TIG welding system is developed, by which welding speed can be controlled and a uniform speed is obtained. Welding of aluminium 5083 plate is carried out for different welding currents and welding speeds. In this work, the effect of welding speed and current on, the tensile strength of the weld, hardness at the three different zones viz. weld metal, HAZ and base metal are investigated. The temperature is measured at the HAZ and base metal. The hardness and temperature on the weld zone and the base metal are greatly influenced by the welding speed and current. It is found that the weld strength is influenced by different values of weld current and speed, but sometimes with high current, welding speed has no specific effect on the tensile strength of the weld. The effect of material deposition rate on the weld strength in uniform welding is studied. The weld thickness to width ratio is an important aspect in the analysis of weld strength. The values obtained for current and speed are taken for optimizing the strength and hardness, using Taguchi method and utility concept.
Modelling the Static Recrystallization Kinetics of Microalloyed TWIP Steels with Different Alloying Contents
Authors: Llanos L. , Pereda Beatriz , López B. , Rodriguez-Ibabe J.M.
Published: November 2016

During hot rolling, austenite recrystallization determines the grain size evolution and the extent of strain accumulation, and therefore, it can be used to tailor the microstructure and mechanical properties of the final product. However, at the moment, models describing the recrystallization kinetics of high-Mn steels are scarce and they do not take into account the effect of the alloying elements present in these steels. The aim of this work is to provide a quantitative model for the determination of the static recrystallization kinetics valid for a wide range of high-Mn steel compositions. Softening data determined for steels with different Mn (20 to 30%), Al (0 to 1.5%) and C (0.2 to 1%) levels at different strain, strain-rate and temperature conditions were analyzed. Static recrystallization of the investigated high-Mn steels follow Avrami’s law, with n Avrami exponents which are temperature dependent and lower than those determined for low C steels. A dependence of the t0.5 (time for 50% fractional softening) on the carbon content has been also observed and it was incorporated into an equation for the calculation of this parameter.
Influence of Second Phases on the Superplasticity of Mg-Tm-Y-CeMM Alloys Containing LPSO-Phases
Authors: Pérez Zubiaur Pablo , Medina Judith , Garcés Gerardo , Adeva Paloma
Published: November 2016

The effect of the nature of the second phases in extruded Mg-TM-Y-CeMM (TM refers to a transition metal) alloys reinforced by intermetallic MgRE (RE refers to a rare earth element) compounds and LPSO-phase on their superplasticity has been evaluated between 300 and 400°C at the strain rate of 10-4 s-1. The data have been compared with those of alloys containing a similar volume fraction of the LPSO-phase. The results evidence that no superplasticity below 350°C was found in the alloys containing exclusively the LPSO-phase while the alloys containing both MgRE compounds and LPSO-phase deform superplastically by grain boundary sliding from 300°C. These differences are related to the different behaviour of MgRE compounds and LPSO-phase in the course of superplastic regime. MgRE compounds assist to accommodate the deformation more easily than LPSO-phase, reducing tendency to develop cavities and extending the time for the occurrence of necking. The size and volume fraction of the respective phases are critical in order to promote enhanced superplastic behaviour. Maximum elongations are attained in the alloys combining similar volume fractions of MgRE compounds and LPSO-phase in which their size is reduced to the maximum. An increase in the particle size of the second phases, especially in the case of the LPSO-phase, hinders the grain boundary sliding mechanism in the alloys.
The Effect of High-Doze Neutron Irradiation on Texture and Substructure Condition of Cladding Tubes from Zr-Based Alloys
Authors: Perlovich Yuriy , Isaenkova Margarita , Krymskaya Olga , Fesenko Vladimir
Published: November 2016

Texture and substructure changes in cladding tubes from Zr-based alloys under neutron irradiation in the atomic reactor during 6 years were investigated by use of X-ray methods. For this aim in the “hot” laboratory the automated X-ray diffractometer was set and the technique to handle with irradiated samples was elaborated. The residual radiation activity of samples correlates with integral texture Kearns parameters of tube, so that the texture weakens as the doze of neutron irradiation grows. Because of the initial substructure inhomogeneity of cladding tubes its changes under neutron irradiation are also inhomogeneous: relatively perfect grains of texture maxima become more distorted, whereas initially distorted grains of texture minima becomes more perfect.
Effect of Secondary Phases Precipitation on Corrosion Resistance of Duplex Stainless Steels
Authors: Pezzato Luca , Lago Mattia , Brunelli Katya , Breda Marco , Piva Enrico , Calliari Irene
Published: November 2016

Duplex Stainless steels (DSS) are biphasic austeno-ferritic steels in which the best combination of mechanical and corrosion resistance properties is achieved for almost equal volume fraction of the phases. These steels are classified according to their pitting corrosion resistance, assessed by the PREN index (Pitting Resistance Equivalent Number) which, although qualitatively, is widely employed as comparison. The present work is aimed to study the pitting resistance of four DSS grades (SAF 2101, 2304, 2205 and 2507) in the as-received condition and after isothermal aging in the critical range 750°C-900°C, to highlight the effect of secondary phases precipitation on the corrosion behavior. The materials were potentiodynamically tested in artificial seawater (pH7) at room temperature and the corresponding Critical Pitting Temperatures (CPT) were determined according to ASTM G150. Secondary phase precipitation mainly affected the lean duplex grades whereas the high-alloyed DSS were more stable even if large precipitation occurred.
An Artistic Approach to Thermal Spray
Authors: Jeandin M. , Borit F. , Fabrègue N. , Rolland G. , Delloro F.
Published: November 2016

“Art is everywhere” to quote Ben, a renowned French contemporary artist. However, there are some areas in which art is more prevalent. Thermal spray is one of them, as this presentation seeks to demonstrate. For this, each of the arts (according to their official classification) is shown to correspond to a specific key point of the thermal spray process for coating: e.g., coating build-up, additive manufacturing, deposition onto brittle and/or temperature sensitive materials (glass, wood, fabrics, polymers), powder optimization, and adhesion. Both modeling and experimental aspects are discussed, focusing on the study of particle-to-particle or particle-to-substrate interfaces, shock phenomena and advanced investigation techniques such as X-ray microtomography or high-speed instrumentation. Plasma spray and cold spray provide the relevant examples that this contribution elaborates. They relate to different industrial sectors such as aircraft-aerospace, luxury, biomedical and the automotive industry. Beyond anecdotal evidence, the discussion aims to show that an artistic approach to thermal spray does help to understand better this powerful coating process.
Evolution of Ni Structure under ECAP and DCAP and Further Annealing
Authors: Popov V.V. , Popova E.N. , Kuznetsov D.D. , Stolbovsky A.V. , Reglitz G. , Divinski Sergiy V. , Wilde G. , Shorohov Evgeniy V.
Published: November 2016

Evolution of structure and properties of Ni under severe plastic deformation by equal-channel angular pressing (ECAP) and dynamic channel-angular pressing (DCAP) has been studied by transmission and scanning electron microscopy and microhardness measurements, and the differences in formation of submicrocrystalline structure under different deformation techniques have been revealed. The thermal stability of structure obtained by these methods is compared. It is demonstrated that under the DCAP processing the material is strengthened faster, by lesser number of passes, and microstructure’s thermal stability is somewhat lower after ECAP compared to that after DCAP, although after equal number of passes ECAP results in a more homogeneous microstructure.
Coupling of Computational Thermodynamics with Kinetic Models for Predictive Simulations of Materials Properties
Authors: Povoden-Karadeniz Erwin , Kozeschnik Ernst
Published: November 2016

We present successful examples of CALPHAD thermodynamics-based precipitation simulations for three important alloy groups: Single-crystal Ni-base superalloy, austenitic stainless steel and hardenable Al-alloy. Underlying physical models for special features, such as, energies of diffuse interfaces between coherent precipitates and matrix, precipitation of incoherent particles at grain boundaries, evolution of excess vacancies during quenching and continuous aging and their role for metastable precipitate nucleation, are discussed.
Solidification Behavior of Aluminum-Copper Based Alloy during Controlled Diffusion Solidification
Authors: Fan Li , Hao Qi Tang , Liu Liang Bo , Shen Rui Qi
Published: November 2016

Controlled diffusion solidification (CDS) is a novel and simple process that enables the formation of non-dendritic microstructure of primary Al phase through mixing two liquid alloys of different composition and temperature together. A quaternary alloy (Al-5.0Cu-0.35Mn-0.25Ti, wt.%), having a similar chemical component with ZL205A, was fabricated using controlled diffusion solidification (CDS) method with different mixing temperature. The mixing temperature of two liquids mostly affects the cast structure especially the primary Al phase. Results show that CDS can reduce the element segregation degree inside the grains. Microstructure evolution during solidification initiates from a primary nucleus firstly and then changed to a non-dendritic grain structure. The thermal analysis confirms the thermodynamic conditions for the formation of non-dendritic grain structure evolution.
Softening Kinetics of Plain Carbon Steels Containing Dilute Nb Additions
Authors: Rakshe B. , Patel J. , Palmiere E.J.
Published: November 2016

The recrystallisation and precipitation kinetics of a plain carbon steel with 0.017 % Nb were studied using the double-hit deformation technique for interpass holding of 5 and 20s. The present study focuses on the effect of prestrain and deformation temperature on recrystallisation behaviour of the investigated steel. The fractional softening was calculated based on the percentage difference between the areas under the interrupted and uninterrupted deformations flow curves. The T5% and T95%, marking the beginning and end of recrystallisation, respectively, are determined as a function of strain. Quantitative microstructural studies validated the findings from the softening studies. The predicated results of recrystallisation regime are found to be in agreement with industrial observation and other experimental measurement for this steel. It can be seen that the dilute additions of Nb can influence the static recrystallisation of austenite under certain rolling condition which may lead to improved mechanical properties of steel.
Innovative Surface Treatments of Titanium Alloys for Biomedical Applications
Authors: Richard Caroline
Published: November 2016

Biomedical engineering is an advanced technology based on an extremely complex development of advanced biomaterials. Since the first Consensus Conference in Chester (UK) on Definitions in Biomaterials of the European Society for Biomaterials, in 1986, biomaterial was defined as ‘a bioinert or bioactive material used in a material advice, intended to interact with biological systems, restore functions of natural living tissues and organism in the body’. In this way, passive metallic materials (as titanium alloys), a broad spectrum of bioceramics, even biopolymers and all combinations of these biomaterials are used for numerous medical devices owing to their high biocompatibility. For example, titanium alloys can be employed for the femoral stems in the total hip joint replacement (trh) or for dental applications. Among the different clinical aims of an implant, a high osseointegration is required and crucial. In order to prevent the alloys from the aggressive body environment, surface modification of implants are employed to render them protection from both wear, corrosion and even tribocorrosion. In addition to the surface treatments, new implant materials are also being fabricated with biocompatible alloying elements to reduce the toxic effects of the alloying elements. These presentation describes the methodologies that could be adapted to overcome some of the factors leading to implant failure. It gives a panorama and shows that the different processes can increase noticeably the performance of the alloy as orthopedic and dental implant. It also gives prospects for the development of new possible ways for enhancing the biosecurity of such material.
Study on the Formation of Stray Grains during Directional Solidification of Nickel-Based Superalloys
Authors: Ridolfi Maria Rita , Tassa Oriana , de Rosa Giovanni
Published: November 2016

Ni-based superalloy single-crystal turbine blades are widely used in gas turbines for aircraft propulsion and power generation as they can be subjected to high service temperature and show high mechanical properties due to the almost total elimination of grain boundaries. Particularly in presence of complex geometry shapes, rare grains nucleating apart from the primary grain, become a serious problem in directional solidification, when characterized by high-angle boundaries with the primary grain, extremely brittle due the elevated amount of highly segregating elements and the absence of grain boundary strengthening elements.
It is of fundamental importance analyzing the physical mechanisms of formation of stray grains, to understand which thermo-physical and geometrical factors highly influence their formation and to find possible ways to reduce the impact of the problem.
In this paper, constrained dendrite growth and heterogeneous grain nucleation theories have been used to model the formation of stray grains in directional solidification of Ni-base superalloys. The study allows to derive the preferred locations of stray grains formation and the role played by the most affecting factors: (i) geometrical: angle of primary grain dendrites with withdrawal direction and orientation of the primary grain with respect to the side walls, responsible for the formation of volumes where the stray grain undercooling is lower than the undercooling of the columnar dendrite tip; (ii) process and alloy: thermal gradient ahead to the solidification front and alloy composition, influencing the columnar dendrite tip undercooling; (iii) wettability of foreign substrates, on which the stray grain undercooling strongly depends.
Effect of Silicide on Dynamic Recrystallization in Near Alpha Titanium Alloy
Authors: Sakamoto Tatsuaki , Otsuka Shohei , Kobayashi Sengo
Published: November 2016

Dynamic recrystallization in Ti-1100 was investigated. Ti-1100 is one of near α titanium alloys and contains Si for improving high temperature mechanical properties. Ti-1100 exhibits martensitic transformation by quenching into iced brine after solid solution treatment. Hereafter specimens subjected to quenching into iced brine and to cooling in air after solid solution treatment are called IBQ specimen and AC specimen, respectively. After tensile test at high temperature, IBQ specimen exhibits morphological change from lath structure to equiaxed structure, but AC specimen does not. It is indicated that dynamic recrystallization occurs during the tensile test of IBQ specimen. Effect of silicide on the dynamic recrystallization was investigated using two specimens: one included more silicide precipitates and the other less. The former specimen shows smaller recrystallized grains than the latter. It is indicated that the specimen including more silicides exhibits smaller recrystallized grains.
Manufacturing of ODS RAFM Steel: Mechanical and Microstructural Characterization
Authors: Testani Claudio , di Nunzio Paolo Emilio , Salvatori Ilaria
Published: November 2016

Ferritic ODS 14Cr steels reinforced by means of Yttrium oxide nanoclusters represent one of the options for future structural applications in nuclear Generation IV reactors. Due to their high tensile properties and resistance to irradiation damage, Oxide Dispersion Strengthened Steels (ODS-S) have been suggested for nuclear fusion applications. The present paper describes the experimental procedure of mechanical alloying, canning and hot extrusion adopted to produce ODS rods. The effect of variations in the processing parameters are also discussed. Hot extrusion has been successfully applied to produce a batch of about 10 kg of ODS steel. Full size ASTM E21 and E8 specimens have been tested from room temperature up to 800 °C. The microstructure characterization of the manufactured materials has been carried out by transmission electron microscopy. Ultimate tensile stress higher than 1350 MPa have been obtained in the as-extruded material and higher than 1100 MPa in samples annealed for 4 hours at 800 °C.
Thermal Effect during Electromagnetic Pulse Welding Process
Authors: Sapanathan Thaneshan , Yang Kang , Chernikov Dmitrii , Raoelison Rija Nirina , Gluschenkov Vladimir , Buiron Nicolas , Rachik Mohamed
Published: November 2016

Magnetic pulse welding (MPW) is a solid state joining process, successfully utilized to join dissimilar metals. This advantage attracted manufacturing industries to fabricate hybrid materials to attain materials with a combination of multiple attributes. The high speed impact during the welding process causes various interfacial phenomena, which have been reported in previous research studies. Combined high speed collision, Joule heating due to eddy current and plastic heat dissipation cause noticeable heating in the workpiece. The heating from the plastic work and collision energy could particularly be significant at the vicinity of the interface compared to other regions of the workpiece. The Joule heating due to eddy current affects the entire workpiece that is prominent before the collision. There is a sharp increase of the temperature at the onset of weld formation due to dissipation of plastic work during the collision. 3D simulations of coupled electromagnetic-mechanical-thermal were carried out to investigate the heating due to the combined Joule heating and plastic dissipation. A case study of MPW, consist of a one turn coil combined with a field shaper, is used to investigate the welding process. The simulations were performed using LS-DYNA®, which has the capability of using both finite and boundary elements to solve the thermo-mechanical problem during electromagnetic forming. The predicted temperature distributions from numerical simulations show expected phenomena of Joule heating and plastic heat dissipation while the analytical approach used to estimate the localized increase in temperature due to supersonic gaseous compression. Minimizing the heating effect by identifying the influencing factors could help to optimize and control the quality of the magnetic pulse welded parts.
Effect of Preparation Conditions of TiB2 Particle Dispersed Al Composites on Microstructure
Authors: Sasaki Gen , Hirose Takaaki , Choi Yong Bum , Sugio Kenjiro , Matsugi Kazuhiro
Published: November 2016

Pure aluminum (Al) has been used as high performance heat sink, electrical line and power supply line because of its light-weight, good thermal and electrical conductivities and high cost performance. On the other hand, the higher performance heat sink and eletrtorical line at room and high tempertture are reqired because of the increment of the power density and higher integration of semiconductor and LED. The use of Al matrix composites is one of suilable solution, because these parts needs multi functional propertes. In this study, titanium die-broide (TiB2) particles was selected as the dispersant in Al matrix composites because of its good thermal and electrical conductivity, and good mechanical propertes. At first, the mixed power of Al and TiB2 particles was obtained from six kinds of mixing process, which parameters are conventional boll milling, ultrasonic vibration after conventinal milling, planetary ball milling, which milling process was performed in wet process with ethanol and dry process. 20 vol. % TiB2/ Al composites was obtained from spark plasma sintering. The dence comopsites with over 98% in relative density with highly dispersed TiB2 particles was obtained from wet mixing process. But the tensile strength of the composites prepared from dry mixing process is higher than that of wet mixing process. The thermal conductivity of the composites is about 120 W/mK, and the obvious diferrence between the wet process and dry process was not observed.
Microstructure Study of Nickel-Based Superalloys after Deep Cold Rolling
Authors: Nagarajan Balasubramanian , Castagne Sylvie
Published: November 2016

Mechanical surface treatments are conducted on aerospace components in order to improve their fatigue life through inducing compressive residual stresses, cold work and smoother surface finish. The microstructures of the component surface and subsurface after treatment influence the crack nucleation and crack propagation significantly. This paper studies the effect of Deep Cold Rolling (DCR), a subsurface process using hydrostatically controlled balls, on the resulting microstructure of RR1000, a nickel-based superalloy used in high temperature aerospace applications. In this study, DCR of RR1000 was conducted by varying the diameter of the roller ball with a constant fluid pressure and overlap. Vickers microhardness was measured to characterize the work hardening behavior during DCR. The microstructure of RR1000 subsurface before and after DCR along both the rolling and transverse directions is analyzed further. The results show that deep cold rolling results in a significant variation on the microstructure of RR1000 including elongation of matrix grains and the precipitates, within a depth of 10 μm from the rolling surface. The change in microstructure along the rolling surface is found to be more prominent than along the transverse directions irrespective of the ball diameter.
Miniaturized Laser Power Sensor via Rapid Phototyping
Authors: Schneider Sylvio , Beyer Harald , Lange Karsten , Bohmeyer Werner , Casalboni Mauro , Richetta Maria , Foitzik Andreas H.
Published: November 2016

This work presents a photolithographic rapid prototyping process for producing thin films ("Rapid Phototyping"). This process allows a quick and cost-effective generation of scalable thermopile microstructures using commercial equipment and materials. Structural widths of 100x250μm can be produced reproducible in a lift-off process with an accuracy of 5 microns vertically and 30 microns horizontally.
High-Pressure Synthesis of Skutterudite-Type Thermoelectric Materials
Authors: Sekine Chihiro , Kato Hirotaka , Kawamura Yukihiro , Lee Chul Ho
Published: November 2016

We have developed a manufacturing system by combination of high-pressure synthesis method using a multi-anvil press, and spark plasma sintering (SPS) method. By means of the system, we have succeeded in synthesizing new filled skutterudite-type thermoelectric materials MmxCo4Sb12 (Mm=mischmetal). The thermoelectric properties of partially filled skutterudite compounds MmxCo4Sb12 synthesized under high pressure have been investigated. The Seebeck coefficient of MmxCo4Sb12 shows negative value, which means n-type conductivity. The highest dimensionless figure of merit ZT value is 0.25 for Mm0.6Co4Sb12 at 700 K.
Kinetics of Submicrocrystalline Structure Formation in a Cu-Cr-Zr Alloy during Large Plastic Deformation
Authors: Shakhova Iaroslava , Belyakov Andrey , Kaibyshev Rustam
Published: November 2016

The grain refinement and kinetics of submicrocrystalline structure formation in a Cu-0.3%Cr - 0.5%Zr alloy during large plastic deformation were investigated. The fraction of high-angle boundaries and the fraction of ultrafine grains were used to estimate the kinetics of grain refinement and submicrocrystalline structure evolution during large plastic deformation. The multidirectional forging (MDF), equal channel angular pressing (ECAP), and high pressure torsion (HPT) were used as methods of large plastic deformation. Comparative analysis showed that the grain refinement process occurred faster during HPT and MDF in comparison with ECAP. The fraction of ultrafine grains achieved almost 1 after 3 HPT turns and after MDF to the total strain of 4; while the one reached only 0.29 after 4 ECAP passes. The modified Johnson-Mehl-Avrami-Kolmogorov equation could be applied to determine the kinetics of grain refinement in copper alloy during large plastic deformation as a function of true strain.
Cooling Curve Based Estimation of Mechanical Properties in High Strength Steel Welds
Authors: Sharma Rahul , Reisgen Uwe
Published: November 2016

The application of high strength steels in welded structures relies on easy to use quality assurance concepts for the welding process. For ferritic steels, one of the most common methods for estimating the mechanical properties of welded joints is the cooling time concept t8/5. Even without experimental determination, the calculation of cooling time with previously introduced formulas based on the welding parameters leads to good results. Because high strength structural steels and weld metals with a yield strength of 960 MPa contain higher quantities of alloying elements, the transformation start temperature Ar3 is found to be outside of the range of 800 °C to 500 °C. This leads to inadequate estimation results, as the thermal arrest caused by the microstructural transformation in this case is not considered.
In this work the usage of the well-proven cooling time concept t8/5 is analyzed using high strength fine grained structural steels and suitable welding filler wires during gas metal arc and submerged arc welding processes. The results are discussed taking into account the microstructure and the transformation behavior. Based on the experimental work, an improved concept is presented.