bluuebunny/crossref_metadata_2025 huggingface dataset:
Nikrothal PM 58 and Kanthal APMT – Alumina Forming High Temperature Steels Offering New Opportunities in Heat Treatment
Authors: Chandrasekaran Dilip , Helander Thomas , Nockert Olovsjö Johanna
Published: March 2024

In this paper a novel nickel-base, alumina forming alloy, Nikrothal PM 58 is introduced. Similar to the previously developed, ferritic, iron-base alloy Kanthal APMT, the alloy bases its corrosion resistance on the formation of an adherent surface alumina layer. They both have high creep strength, due to a dispersion strengthened microstructure from the powder metallurgical processing route. This unique combination of properties enables application temperatures ranging from 1472 F (800°C) to 2372 F (1300°C) and new possibilities to design high temperature components like mesh belts, furnace rollers and muffles. Mechanical and corrosion properties for Nikrothal PM 58 at 2012 F (1100°C) and 2192 F (1200°C) are presented and compared with other commercial high temperature alloys.
Induction Hardening Inductors and Process Development
Authors: Midea Sandra J. , Lynch David
Published: March 2024

Although great strides are being made in the simulation of induction patterns, most of today’s inductor design and validation activities are still done through experience and experimentation. This paper provides a brief overview of how an inductor is designed, fabricated, and prepared for integration into manufacturing. Each aspect of its manufacture is critical to deliver a hardening inductor capable of meeting engineering drawing requirements and to be ready for production. The paper covers determination of requirements, inductor design, fabrication and assembly, process development, inductor characterization, metallurgical validation, and delivery of a production-ready inductor. Each step is described, and important considerations for each are presented.
Computer Simulation of Single-Shot Induction Hardening Processes
Authors: Russell Collin A. , Rudnev Valery , Li Zhichao , Ferguson B. Lynn
Published: March 2024

In single-shot hardening applications, heat treated components often feature a variety of geometric complexities including variable wall thicknesses, sharp diameter transitions, lightening holes, slots, etc. Due to the inherent 3D electromagnetic nature of single-shot coils and the complex geometry components which they must accommodate, the design and optimization of single-shot hardening coils is typically a demanding and intricate task. This paper presents combined electromagnetic-thermal and thermal-mechanical FEA simulation results for the single-shot induction hardening of a power transmission shaft. The simulation results, including electromagnetic, thermal, metallurgical, and mechanical data demonstrate the value of computer simulation in the design and development of single-shot induction hardening systems.
Understanding the Induction Hardening Circuit
Authors: Stuehr William I.
Published: March 2024

The objective of this paper is to provide an understanding of the electrical circuit for induction hardening. This includes the power supply, workstation, and inductor. Step by step procedures are provided using a commercial power supply and workstation as an example. The paper addresses questions such as: What is an inductor? How does the inductor connect to a scanner? How is quenching performed in induction? What is load tuning? How do I load tune an induction circuit? How does the induction power supply work? How do I verify induction hardening results? This paper also provides a brief history of induction hardening and discusses how the development of the technology impacts induction hardening today.
Advancements in Control and Data Management for Heat Treatment
Authors: Miller Steve
Published: March 2024

Modern technological advancements make it easier to achieve accurate control to meet AMS2750E and CQI9. Today’s Industrial technologies have advanced rapidly alongside electronic innovations that improve accuracy and control. In years past, there was a certain difficulty associated with accuracy from older existing controls to new modern process controls due to the level of complexity and cost involved. Today, equipment manufacturers are integrating a variety of new technology to improve accuracy for more accurate monitoring. This paper looks at some of the old and new technology innovations for input accuracy regarding both analog and digital signals.
Test Piece Representation of Carburized Gear Heat Treatment
Authors: Pershing Michael A. , Maniruzzaman Mohammed
Published: March 2024

Test pieces are often used for hardened depth and microstructure checks on carburize and harden heat treatment processes so that actual parts are not destroyed for the sake of quality assurance. For gear heat treatment, this is especially important because of costly prior processing. This paper reports on a study to determine the proper size and material of a cylindrical test piece that could be used as an appropriate indicator of the hardened depth and microstructure of the actual gear. Heat treat simulation is used to examine cooling rates for various diameters of test pieces to see how they compare to different modules of tooth sizes on gears. The surface cooling rates up to depths of 1.5 mm are examined to size the test piece correctly.
Developing Rotary-Arm Type Test System with a Small Platinum Ball Probe for Determination of Cooling Characteristics of Quenchants
Authors: Arimoto Kyozo , Shimaoka Mitsuyoshi , Ikuta Fumiaki
Published: March 2024

Performances of quenchants have been enhanced and maintained based on their cooling characteristics determined by specific test systems. A rotary-arm type test system with a small ball probe has been developed for this purpose by making prototypes. Its unique concept derived mainly from a circular motion of a small ball probe in quenchants was proposed by Tawara in 1941. The prototypes have been realized by current heating, measuring and mechatronics techniques. Finally the probe material has been changed from nickel alloy to platinum for resolving the discoloration and thermal aging problems on the probe surface. The performance of the prototypes has been verified by systematic tests using specific quenchants under various cooling conditions.
An Inverse Method for Determining Steel Properties for Simulation of Phase Transformations During Quenching
Authors: Biba N.V. , Shitikov A.A. , Alimov A.I.
Published: March 2024

Accurate simulation of phase transformation during quenching of steels requires comprehensive knowledge of thermal and physical properties of the material. In cases when reliable material data are not available they can be obtained by a two-stage inverse method proposed in the paper. It includes a Jominy test of a specimen with thermocouples. At the first stage, we obtain TTT diagrams by means of analyzing cooling curves for several regions of the specimen obtained from experimental results. The second stage includes correction of material thermo-physical properties, i.e. the thermal conductivity and specific heat for each phase as well as estimation of the latent heat for each phase transformation. Parameters fitting is carried out iteratively by comparing FEM simulation and experimental results. Varying of parameters is performed with evolutionary methods of multi-parameter optimization. The developed method is implemented in QForm commercial software.
Numerical Model of Controlled Cooling of Steel Hot Rolled Bars
Authors: Smoljan Božo , Iljkić Dario , Senčić Bojan , Vertnik Robert
Published: March 2024

Numerical model of controlled cooling in production of steel hot rolled bars was developed. By numerical model of controlled cooling is possible to predict a transient temperature field, microstructure evolution and hardness of rectangular steel bars during their cooling in cooling beds. The numerical model of transient temperature field is based on control volume method. The algorithm for prediction of hardness and microstructure distribution in steel bars is based on continues cooling transformation, (CCT) diagrams and real chemical composition. The numerical model and algorithm is completed to solve problems in controlled cooling of hot rolled bars in cooling beds. The controlled cooling are performed by special placement of hot rolled bars on cooling beds. Numerical model and computer program was experimentally verified by simulation of real industrial production of low alloyed steel bars. The verification of developed numerical model was performed by comparison of simulated hardness with experimentally evaluated results.
Evaluation and Control Technique of Cooling Unevenness by Quenching Oil
Authors: Homma Rikki , Ichitani Katsumi , Matsumoto Mika , Steiger Greg
Published: March 2024

In the heat treating process, it is important for parts to be cooled uniformly in order to reduce distortion while obtaining target hardness. However, it is difficult to cool the parts uniformly due to the presence of the vapor blanket stage in oil quenching. In this study, we investigated the influences of cooling unevenness in various heat treatment conditions, such as the types of oils having different vapor stage lengths, and using varying agitation and oscillation rates with these oils. We found that cooling unevenness was decreased by using the quenching oil with a shorter vapor blanket stage length. Additionally, the cooling unevenness was decreased by agitation and oscillation compared to quenching without agitation. In conclusion, we found selecting a quenching oil with the shortest vapor blanket stage length and combining agitation and oscillation was the most effective method in reducing the distortion of parts after oil quenching.
Thermal Fatigue in Hot Work Tool Steels - A Review
Authors: Ribeiro da Silva Junior Ruy , Totten George E. , Carmo Vendramim João , Franceschini Canale Lauralice de Campos
Published: March 2024

Thermal fatigue is a dominant mechanism that causes premature failure in components exposed to high temperature. In order to extend the useful life of tools for hot work, studies have been conducted trying to understand the mechanisms involving thermal fatigue. Thus, different types of materials combined with different parameters of thermal and surface treatments have been investigated using thermal fatigue tests. This review addresses the main aspects of thermal fatigue as well as the main alternatives used to increase the resistance of the material to this type of failure.
Simulation of Temperature Profile in Longitudinal Welded Tubes During High-Frequency Induction Welding
Authors: Das Prerana , Inge Asperheim John , Grande Bjørnar , Petzold Thomas , Hömberg Dietmar
Published: March 2024

The temperature profile in the Heat Affected Zone (HAZ) during induction welding is one of the most important factors determining the weld quality of High-Frequency Induction (HFI) welded steel tubes. In this work, numerical computation of the 3D temperature profile in the steel tube has been done by coupling the electromagnetic model with the thermal model. The high-frequency current and the magnetic fields in the tube, coil and impeder have been evaluated. The resulting power from the induced current is used to evaluate the temperature in the joining edges of the tube. The continuous tube movement has been implemented by considering an additional transport term in the heat equation. The simulations consider non-linear electromagnetic and thermal properties of the steel when it undergoes temperature rise to the welding temperature. The temperature profile from the resulting simulation gives information to control the subsequent process of joining the edges of the steel tube.
True Single-Piece Flow Case Hardening for In-Line Manufacturing
Authors: Hart Tom , Korecki Maciej
Published: March 2024

Case hardening by carburizing is the most common heat treatment in mass production, which relies on atmosphere, or vacuum carburizing followed by oil or gas quenching and finally by tempering. Parts being heat-treated undergo the process in a configuration of a batch consists of hundreds or even thousands pieces. Under these circumstances, individual parts can’t help but be exposed to different process parameters in terms of temperature, atmosphere and quenching depends on their position within the batch. Parts near the outer portion of the load see a more rapid rise in temperature, are first exposed to the carburizing atmosphere and are more effectively quenched than parts located in the center of the batch. This can lead to significant variation from part to part and load to load; the resultant effective case depth deviation can be as high as 50%. Similarly, during quenching from hardening temperature distortion becomes highly unpredictable and unrepeatable. Modern industry demands greater precision and repeatability of results beyond those achievable by so-called traditional batch or continuous technologies and their associated equipment. Elimination of batches and focus on individual parts is the only true way to advance the industry. The article will introduce the first operational system for truly single-piece flow method for case hardening by low-pressure carburizing and hardening by high-pressure gas quench. The system treats each part individually and as such provides virtually identical process parameters, which results in extremely accurate and repeatable results. Quenching one part at a time in a specially design chamber, achieves more precise control and significantly reduces distortion so as to all make it possible to avoid post heat treatment hard machining operations. This single-piece flow heat treatment method is easily adapted into manufacturing and can be directly integrated into in-line manufacturing operations, working directly with machining centers. Materials handling and logistical issues are eliminated thus saving time and reducing unit cost. The results achieved on series of automotive gears will be reported and demonstrate incredible accuracy and repeatability, while significantly reducing distortion. Productivity and process costs prove the system to be highly competitive with other technologies. These proven advantages and savings.
Vacuum Carburizing Steel Alloys Containing Strong Carbide Formers
Authors: Ferguson B. Lynn , Li Zhichao , Sims Justin , Yu Tianyu
Published: March 2024

Carburizing grades of high strength steels, such as Ferrium C- 64 alloy, contain strong carbide forming elements such as chromium and molybdenum. Alloys with high amounts of strong carbide formers can form stable carbides during carburization that effectively block carbon diffusion and retard the carburization process. This is especially true for low pressure carburization. To achieve the desired case depth, the low pressure carburization process consists of a series of rapid boost and longer time diffusion cycles. One problem is how to determine an acceptable carburization schedule. This paper will discuss a methodology used to develop the data for Ferrium C-64 so that a proper low pressure carburizing schedule could be determined. Integral parts of this methodology are experiments to determine carbon diffusion rates, carbide formation kinetics, and carbide dissolution kinetics, and use of these data in computer software to simulate the process and to determine the proper schedule.
Copper Evaporation During Low Pressure Carburizing
Authors: Jones Trevor , Osterman Virginia , Jordan Donald
Published: March 2024

Low pressure carburizing (LPC) in a vacuum furnace is increasingly the preferred method of case hardening for aerospace gears, and acetylene is often one of the gases used in the process. Selective case hardening is common with gears, where certain sections of a part are “stopped off” or “masked” to prevent carburization at those locations. For aerospace parts, the masking used is typically copper electroplating. The low pressures and high temperatures used in LPC lead to copper evaporation, which contaminates the vacuum furnace hot zone and components. In a worst-case scenario, deposited copper can lead to short-circuiting of power feedthroughs. This study looks at the effect of vacuum and partial pressure gases on copper evaporation and its application in production processes.
Friction and Wear Properties of (Ti,Mo)(C,N) Hardmetal Coatings Prepared by Gas and Liquid Fuel HVOF Processes
Authors: Berger L.-M. , Kitamura J. , Kasahara F. , Yamada J. , Sato K. , Vuoristo P. , Milanti A. , Niemi K. , Houdková Š. , Savková J.
Published: March 2024

This paper presents the results of a study on the tribological properties of TiC-based coatings deposited by HVOF spraying. Four powder feedstocks consisting of (Ti,Mo)(C,N) hardmetal with Ni and Co binders were prepared by agglomeration and sintering. The feedstocks differ in composition and particle size distribution, the latter being optimized for fuel type and equipment requirements. Coating specimens are evaluated based on microstructure, hardness, bonding strength, and friction and wear behavior. The results are presented and correlated with spray parameters, equipment differences, and feedstock characteristics.
Macroporous Titanium Coatings by Thermal Plasma Spray
Authors: Robotti P. , Sabbioni A. , Glass L. , George B.
Published: March 2024

This paper presents a summary of some of the research conducted on sponge-like titanium coatings developed for orthopedic use. It assesses the pore structure, adhesion properties, and in-vitro and in-vivo biological characteristics of porous titanium coatings deposited by vacuum plasma spraying on metals, PEEK polymer, and two bioceramics, Mg-toughened ZrO2 and ZrO2-toughened Al2O3. The plasma sprayed coatings show good flexibility in terms of pore size (100-800 µm), overall porosity (40-70%), and coating thickness (600-1500 µm).
Study on the Restoration of Aluminum Aerospace IVD Coatings Using Cold Gas Dynamic Spray
Authors: MacDonald D. , Jodoin B. , Gaydos S. , Pollack M. , Falkowski J.
Published: March 2024

Ion vapor deposition is a physical vapor deposition process often used to apply pure aluminum coatings to aerospace parts for corrosion protection. These coatings, however, are vulnerable to damage during manufacturing and use, leaving the underlying material susceptible to corrosion. The aim of this study is to develop an economical and practical technique for the repair and restoration of damaged aluminum IVD coatings using available cold gas dynamic spraying equipment. Based on the porosity, surface finish, adhesion strength, and corrosion performance of the repair coatings, cold gas spraying is shown to be a strong candidate for restoring damaged aluminum coatings on aerospace parts.
Strength and Wear Properties of Stainless Steel Coatings Produced by Cold Spray with Various Powder Sizes
Authors: Vo P. , Irissou E. , Kudapa S. , Nestler M.
Published: March 2024

Cold spray processing of stainless steel coatings, which represent a cost-effective method for wear and corrosion resistance, has been demonstrated as technically feasible. However, these coatings have very low tensile strength in the as-sprayed condition and may also exhibit a marginally higher wear rate. In this study, the cold spraying of 316L stainless steel coatings was investigated to assess the effect of powder size distribution and post-spray heat treatment on strength and wear properties. Coatings on aluminum and steel substrates were produced with a feedstock powder obtained in three particle size distributions. All coatings were deposited under the same conditions using nitrogen as the propellant gas, and then annealed at the optimum temperature. The microstructure and mechanical properties of both as-sprayed and heat-treated coatings were evaluated and the results are presented in the paper.
Multi-Response Optimization of Process Parameters for Low-Pressure Cold Spray Coating Process Using Taguchi and Utility Concept
Authors: Goyal Tarun , Sidhu T.S. , Walia R.S.
Published: March 2024

This paper presents the decision-making process used to simultaneously optimize the thickness and density of copper coatings produced by low-pressure cold spraying. Utility values based on both process parameters are analyzed for optimization using a Taguchi approach. The selected input parameters of powder feeding arrangement, substrate material, air stagnation pressure, air stagnation temperature, and standoff distance are shown to significantly improve the utility function of interest. The percentage contributions of the input parameters to optimize coating density and thickness are substrate material (50.03%), standoff distance (28.87%), air stagnation pressure (6.41%), powder feeding arrangement (4.68%), and air stagnation temperature (2.64%).
Velocity Measurement of Sprayed Particles and Coatings Fabrication of Titanium Alloys by High-Pressure Warm Spray
Authors: Kuroda S. , Molak R.M. , Watanabe M. , Araki H. , Katanoda H. , Sun B. , Ohno N. , Fukanuma H.
Published: March 2024

This study investigates particle velocities achieved by high-pressure warm spraying. Commercially pure titanium (CP-Ti) and Ti-6Al-4V powders were deposited on different substrates while varying spray parameters to determine their effect on particle velocity and coating quality. Particle image velocimetry was used to measure particle velocity, which peaked at 1,000 m/s. Coatings obtained under optimized conditions were characterized based on porosity, oxygen content, and hardness. The results show that the increased velocity of high-pressure warm spraying has significant beneficial effects in terms of improving density and controlling porosity and oxygen content.
Effect of Liquid Feedstock on Downstream Cold Spray Nozzle
Authors: Farvardin E. , Karimi M. , Villafuerte J. , Dolatabadi A.
Published: March 2024

In this study, a downstream injection cold spray nozzle is modeled numerically under various loadings. Instead of micron-sized particles, liquid feedstock as a carrier of nanoparticle suspension is fed into the nozzle through a port located 6 mm downstream of the nozzle throat at the diverging section. Water is used as the liquid carrier with a droplet size distribution of 5-100 µm and liquid-to-gas ratio ranging from 5 to 15%. The radial injection of droplets is simulated by Lagrangian particle tracking which includes the effects of heating and evaporation. The effect of the feedstock on downstream flow is analyzed and the optimum solid-to-liquid fraction in the suspension is determined.
Comparable Study of Electrical and Mechanical Properties in Plasma Sprayed Alumina Coatings
Authors: Tosaki T. , Kobayashi Y. , Ohta K. , Kitamura J.
Published: March 2024

In this work, alumina coatings are produced by air plasma spraying (APS) using dense powders ranging in size from 3 to 36 µm and one porous powder with an average particle size of 33 µm. Two spray systems were used, one rated at 40 kW, the other at 100 kW. The powders were applied to grit-blasted Al 6061 and low-carbon steel substrates. Coatings applied to Al 6061 using the high-power sprayer and 3 µm powder peeled off, likely due to thermal shock and mismatch. For all other coatings, the microstructure was examined by cross-sectional SEM, porosity was estimated via optical microscopy, and dielectric strength and volume resistivity were measured. Coatings formed from 3 µm powder were found to be dense with a mostly γ-phase crystal structure. Surprisingly, however, their volume resistivity was lower than that of more porous coatings with high amounts of α-phase. The findings show that, in the case of resistivity, spray equipment has a bigger influence than particle size, but with coating density, the opposite is true.
Investigation of a Pulsed Current Wire Arc Spray Process
Authors: Kirner S. , Schein J. , Forster G.
Published: March 2024

Much of the research being done in arc wire spraying deals with new nozzle geometries and secondary atomizing gas flows. This study, instead, focuses on pulsed current power. Spray trials are conducted using a conventional electric arc gun and an inverter that produces large current pulses with controlled amplitude and frequency. Droplet formation and detachment are monitored with a high-speed camera that records shadow images synchronized with current and voltage measurements. The images are processed into analog signals that are converted to the frequency domain and the Fourier coefficients are plotted, providing a relative measure of the influence of pulse frequency on droplet ablation. The results suggest that arc spraying can be improved using pulsed current power and that gas pressure and pulse time have greater influence than pulse frequency.
Structure and Properties of HVOF and Plasma Sprayed Ceramic Alumina-Chromia Coatings Deposited from Fused and Crushed Powders
Authors: Vuoristo P. , Niemi K. , Matikainen V. , Hyvärinen L. , Koivuluoto H. , Berger L.-M. , Scheitz S. , Shakhverdova I.
Published: March 2024

Different feedstock powder compositions of the alumina-chromia system were deposited on steel substrates by various methods, including conventional plasma spraying, three-anode plasma spraying, and HVOF. The powders used for plasma spraying had particle sizes of -38+10 µm and for HVOF spraying -25+5 µm and -25+10 µm. The coatings were evaluated by their microstructure, phase composition, and corrosion, wear, and electrical properties. The study shows that wear properties depend strongly on the spray process and that coatings obtained by HVOF spraying have dense structures and excellent wear behavior. Coatings produced by the three-anode plasma process, despite their higher porosity, were found to be harder than conventional plasma coatings and can be sprayed with higher feed rates. The coating properties do not appear to have a linear dependence on chromia content.
Structural Modifications on Material Surfaces by Thermal Nanoparticle Spraying and Microline Patterning
Authors: Kirihara S.
Published: March 2024

This study deals with two new material deposition processes in which raw materials are in the form of a thixotropic slurry. In one case, the slurry (Al2O3 nanoparticles in an acrylic resin) is misted into an arc plasma jet and sprayed on a stainless steel substrate. By varying the volume content of nanoparticles and slurry supply rates, investigators were able to achieve uniform droplets, resulting in fine Al2O3 layers free of microcracks and pores. In the other process evaluated, pure aluminum particles were dispersed in a photosensitive resin, producing a slurry that was spread on stainless steel substrates then patterned with a UV laser. The patterned metal particles were heat treated, creating iron-aluminide intermetallic phases through reaction diffusions. The microstructure and composition of the patterned lines are analyzed by SEM and XRD and surface stress distributions associated with a Hilbert fractal pattern are simulated via finite element analysis.
3D Wear Analysis of Thermal Spray Coatings
Authors: Tillmann W. , Luo W. , Selvadurai U.
Published: March 2024

This study investigates the wear resistance of WC-FeCSiMn coatings deposited on 3D surfaces by two-wire arc spraying. Wear behavior was evaluated by means of pin-on-disc testing, pin-on-rotating tube testing, and a method in which a robot arm moves a pin over test specimens with arbitrary surface geometries. Residual stresses were determined by incremental hole drilling and were found to have a dependency on substrate geometry. After wear testing, a 3D profilometer determined wear volume and coating surfaces were examined by SEM. The results indicate that wear resistance is strongly influenced by the geometry of the substrate.
Tungsten Carbide Deposition Processes for Hard Chrome Alternative: Preliminary Study of HVAF vs. HVOF Thermal Spray Processes
Authors: Lyphout C. , Kitamura J. , Sato K. , Yamada J. , Dizdar S.
Published: March 2024

This paper presents the results of a preliminary study comparing high-velocity oxyfuel and airfuel spraying for the deposition of tungsten carbide coatings as an alternative to electrolytic hard chrome plating. Two tungsten carbide powders with a Co matrix and two with a Co-Cr matrix were sprayed on steel substrates using commercial HVOF and HVAF equipment. The coatings obtained are evaluated by means of SEM and XRD analysis, microhardness and adhesion measurements, and corrosion and wear resistance testing. Detailed results are presented and discussed with emphasis on the role of carbide grain size, carbide contiguity, and binder mean free path. In general, HVOF coatings show significantly higher dry wear resistance, owing to the presence of coarser primary carbides from the initial coarser powder. HVAF coatings, on the other hand, exhibit lower porosity and finer well-distributed primary carbides, giving them an advantage in terms of sliding wear resistance.
External Powder Injection in Twin Wire Arc Spraying to Control the Coating Composition
Authors: Tillmann W. , Abdulgader M. , Hagen L.
Published: March 2024

This study investigates the potential of external powder injection for producing functionally graded coatings by twin wire arc spraying. In spray trials, the position of the injection port was altered along the spray axis and perpendicular to the arc and different powders and carrier gases were used. Real-time images were captured by a high-speed camera during spraying to detect correlations between gas flow rates, hard particle wetting, and atomization of the molten pool. The optimal location for injection was found to be dependent on the size and density of the powder and the flow rate of the carrier gas. In the case of embedding B4C in a Fe-based matrix, a strong metallurgical bond was formed, confirming that powder injection is a viable approach for controlling the composition of twin wire arc sprayed coatings.
Improved Thermal Cycling Durability of Thermal Barrier Coatings Manufactured by PS-PVD
Authors: Rezanka S. , Mauer G. , Vaßen R.
Published: March 2024

The durability of columnar TBCs produced by PS-PVD are strongly influenced by the compatibility of the metallic bond coat and ceramic topcoat. Studies have shown that a smooth bondcoat surface improves thermal cycling performance and that further improvements are possible by optimizing the formation of the thermally grown oxide layer. In this work, preheating and the deposition of the first coating layer are varied in order to adjust oxide growth. The results show that thermal cycling lifetimes can be more than doubled without a major increase in manufacturing time.
Controlling YSZ Abradable Erosion Performance by Optimizing Spray Parameters
Authors: Hawkins A. , Wellman R. , Craig M. , Nicholls J.R. , Laul K. , Shankar R.
Published: March 2024

This study investigates the effect of plasma spray parameters on the erosion rate of abradable seals used for clearance control in gas turbine engines. Coating samples were sprayed using YSZ powder containing polyester that was entrapped in the deposit then subsequently removed by heating. Test results show that erosion behavior is influenced by gun voltage and spray distance. A higher voltage results in a denser coating with a lower erosion rate. Increasing spray distance, on the other hand, increases porosity, which results in a higher erosion rate. Further analysis shows that the erosion rate is proportional to the inverse square of the spray distance and the square of the gun voltage.
Effect of Substrate Hardness and Spray Angle on the Deposition Behavior of Cold Sprayed Ti Particles
Authors: Yin S. , Suo X.K. , Liao H.L. , Wang X.F. , Li W.Y.
Published: March 2024

In this study, finite element analysis and experimental observation are used to evaluate the effect of substrate hardness and spray angle on the deposition of cold-sprayed Ti particles. It is found, in the case of Cu substrates, that both the particle and substrate deform during impact, resulting in a large contact area. Metallurgical bonding is highly likely under such conditions, facilitating formation of thick coatings. In the case of Al substrates, although the contact area is smaller, Ti particles are trapped by the softer substrate material, resulting in mechanical interlocking and a relatively thick coating. In the case of stainless steel substrates, mechanical interlocking does not occur due to the relative hardness of the material, which limits coating thickness. The results of the study also show that decreasing the spray angle reduces interfacial contact area and coating thickness, while increasing porosity.
Microstructure and Magnetic Properties of Atmospheric Plasma Sprayed Fe-40Al Coatings Obtained from Nanostructured Powders
Authors: Song B. , Dong S.-J. , Fenineche N.-E. , Liao H.-L. , Coddet C. , Grosdidier T.
Published: March 2024

In this work, Fe-40Al coatings are produced by atmospheric plasma spraying using a nanostructured feedstock exhibiting a very low degree of order. The as-sprayed deposits consist of fundamental FeAl phases, Fe3Al phases, and oxides and are found to be ferromagnetic due to the low degree of order and the presence of unmelted nanoparticles retained from the feedstock. The magnetic properties of the coatings are shown to be heterogeneous in the parallel and vertical direction.
Effect of Ceramic Content on the Microstructure and Wear Behavior of Al/SiC Composite Coatings by Cold Spraying
Authors: Wang H.-T. , Ji G.-C. , Wang R.-Y.
Published: March 2024

In this study, Al-SiC composite coatings are produced by cold spraying ball-milled Al powders with different volume fractions of SiC particles. The morphology and microstructure evolution of the powder during ball milling are evaluated along with the effect of SiC content on the microstructure and wear behavior of the coatings. The results show that dense Al-SiC coatings with different volume fractions of SiC particles can be fabricated by cold spraying and that abrasive wear resistance is improved by raising the volume fraction of SiC particles. Wear surfaces indicate that the predominant wear mechanism is gouging of the soft Al matrix in the early stages and cracking and spalling of SiC particles in the latter stages. The dispersed SiC particles serve to protect the matrix from wear products thus raising the wear resistance of the coatings.
Prediction of Critical Velocity during Cold Spraying Based on a Coupled Thermomechanical Eulerian Model
Authors: Wang F.F. , Li W.Y. , Huang C.J. , Yu M. , Liao H.L.
Published: March 2024

In the present work, a coupled thermomechanical-Eulerian model was developed to calculate particle impact behavior during cold spraying. The model is based on temperature-displacement elements and is capable of nonlinear transient analysis of impact deformation and heat conduction. Simulation results show that heat conduction has a major effect on temperature distribution within the particle, but little influence on particle deformation. The FEA model is also used to calculate critical velocities of commonly sprayed materials and the results are evaluated based on the morphology of deformed particles and plastic strain analysis.
Influence of the Substrate’s Shape Complexity on the Coating Properties Produced by HVOF Spraying of Fine WC-12Co (2-10 µm) Powders
Authors: Tillmann W. , Hollingsworth P. , Baumann I. , Flossbach S. , Müller H. , Wiederkehr T.
Published: March 2024

This study investigates the influence of component geometry, particularly the outer radius of curved surfaces, on the hardness and porosity of HVOF-sprayed WC-Co coatings as well as the deposition rate. A fine agglomerated and sintered WC-12Co powder of spherical shape was sprayed on steel substrates. Process parameters were held constant, while the radius of curvature was varied between 5 and 40 mm. The results show that HVOF spraying is better for depositing fine particles on curved surfaces than other spray processes, although the deposition rate decreases compared to flat substrates.
Hybrid Polymer Composites for Structural Purposes
Authors: VALIEV A.I. , SULEIMANOV A.M.
Published: March 2024

A review of foreign and domestic literature and practice on the use of polymer composites for structural purposes in the field of construction is carried out. The main factors hindering the widespread introduction of polymer composites in the construction sector have been identified: polymer composite profiles manufactured at the factories duplicate the shapes of profiles of metal analogues with isotropic mechanical properties; not all structural elements made of polymer composites meet the defining condition of strength testing according to the second limit state (for deformations), this leads to an increase in cross-sections, a decrease in the pitch of structural elements; problems related to insufficient information on durability, involving the use of overestimated values of the coefficients of the working conditions of the material due to insufficient knowledge of the properties and a significant spread of physical and mechanical characteristics; problems related to import substitution of polymer composite components. A scientific problem has been formulated, which consists in studying the mechanisms of formation of the adhesive strength of hybrid composites at the fiber-matrix interface, followed by the development of effective ways to regulate their condition in order to ensure a strong connection. The actual tasks, the solution of which needs to be concentrated in order to accelerate the process of introducing hybrid polymer composites for structural purposes, are presented
Trends in the Development of Scientific Directions in the Field of Road Construction Materials in Russia (Review)
Authors: INOZEMTSEV S.S. , SUSANINA T.V. , STIBUNOV D.V. , KEITA M.L.F.
Published: March 2024

The presented article analyzes the research topics for the period from 2000 to 2023, the result of which was the defense of dissertations for the degree of Candidate and Doctor of Sciences in order to identify trends in the development of scientific directions in the field of road construction materials. Open sources, including electronic ones, were used as the research base, from which articles with the results published in the preparation of at least 100 dissertations defended in the scientific specialty “Building Materials and Products” were analyzed. For the convenience of the analysis, the works are summarized in tables: by the object of research; by the type of technical solution. It is concluded that during the period under review, there was a transformation of research directions from traditional types of materials to multicomponent composites with a complex improved structure. It is shown that in order to test the results of research in the preparation of dissertations in the period under review, the average number of publications increased from 5-6 to 13-23. The generalized tasks of further development of scientific directions in the field of road construction materials are formulated. A list of topical issues of modern science in the field of road construction materials has been identified.
Adverse Effects of Rosemary (Rosmarinus officinalis L.) on Reproductive Function in Adult Male Rats
Authors: Nusier Mohamad K. , Bataineh Hameed N. , Daradkah Haytham M.
Published: March 2024

Ingestion of rosemary ( Rosmarinus officinalis L.) by two groups of adult Sprague-Dawley rats at levels of 250 and 500 mg/kg body wt for 63 days was investigated for its effects on fertility. Body weight and absolute and relative testes weights were not affected, but the average weights of epididymides, ventral prostates, seminal vesicles, and preputial glands decreased significantly. A significant decline in spermatogenesis in testes due to a decrease in the number of primary and secondary spermatocytes and spermatids in treatment group 2 (500 mg/kg) is attributed to a significant decrease in testosterone. Sperm motility and density were also significantly decreased in the cauda epididymis and in the testes of rosemary-treated male rats in group 2. In addition, the treatment markedly increased the number of fetal resorptions in female rats impregnated by group 2 males, thereby reducing their fertility. Exp Biol Med 232:809–813, 2007
Chronic Resveratrol Enhances Endothelium-Dependent Relaxation but Does Not Alter eNOS Levels in Aorta of Spontaneously Hypertensive Rats
Authors: Rush James W. E. , Quadrilatero Joe , Levy Andrew S. , Ford Rebecca J.
Published: March 2024

Spontaneously hypertensive rats (SHRs) were administered the red wine polyphenol resveratrol in drinking water at 0, 0.448, or 4.48 mg/l (control, low, or high, respectively) for 28 days. The low dosage was chosen to mimic moderate red wine consumption. After the treatment period, thoracic aorta rings were excised for in vitro assessment of vasomotor function. Chronic resveratrol significantly improved endothelium-dependent relaxation to acetylcholine (Ach), increasing maximal values to 80.8% ± 5.2% and 80.8% ± 5.0% in low and high groups, respectively, compared with 60.7% ± 1.4% in controls ( P < 0.01). This treatment effect was eliminated in the presence of the endothelial nitric oxide synthase (eNOS) blocker Nω-nitro-l-arginine methyl ester. Resveratrol did not affect relaxation to sodium nitroprusside or systolic blood pressure in SHRs. In contrast to the SHR results, chronic resveratrol in Sprague Dawley rats did not affect vasomotor function in aorta rings in response to Ach. Hydrogen peroxide was reduced in the SHR thoracic aorta by a high dosage of resveratrol ( P < 0.05), but it was not significantly altered in other tissues tested. Thoracic aorta immunoblots revealed no significant treatment effects in SHRs on eNOS, superoxide dismutases 1 and 2, gp91phox, or Hsp90. Thus, these data provide novel evidence of improved endothelium-dependent vasorelaxation in hypertensive, but not normotensive, animals as a result of chronic resveratrol consumption mimicking dosages resulting from moderate red wine consumption. This response was not dependent on increases in eNOS expression but was dependent on improved NO bioavailability.
УПРАВЛІННЯ ПРОЄКТНОЮ ДІЯЛЬНІСТЮ ПІДПРИЄМСТВА НА ЗАСАДАХ AGILE-МЕНЕДЖМЕНТУ ТА СУЧАСНИХ ІНФОРМАЦІЙНИХ ТЕХНОЛОГІЙ
Authors: ЯДУХА Сергій , ДУРАЧ Андрій , СЕМЕНЧЕНКО Віталій , ЯБЛОНСЬКИЙ Тарас
Published: March 2024

У статті розглянуто сутність поняття «проєкт» та визначено, що існують наступні підходи до його розуміння: сукупність дій або діяльність (змін), комплекс взаємопов’язаних заходів, комплект документів, процедур і усіх необхідних заходів з метою створення інноваційного продукту, набір процесів і завдань з метою досягнення мети. Наведено авторське визначення поняття «проєкт», зокрема під проєктом слід розуміти комплекс взаємопов’язаних заходів та процедур, що розроблені з метою досягнення поставлених цілей за рахунок змін у об’єкті управління із врахуванням ресурсних обмежень. Виділено основні характеристики, які визначають сутність проєкту і роблять його унікальним, зокрема:цілі та завдання, обмеження, ресурси, часові рамки, складність та ризики. Обґрунтовано актуальність використання agile-менеджменту в проектній діяльності підприємства. У статті охарактеризовано agile методології (eXtreme Programming (XP), Scrum, Acceptance Test-Driven Development (ATDD), Dynamic Systems Development Method (DSDM), Lean Software Development, Test Driven Development (TDD). Зазначено, що Agile-менеджмент проєктів (гнучке управління проектами) – це методологія, яка акцентує увагу на адаптивності до змін, а її основна ідея полягає в тому, щоб гнучко реагувати на зміни у вимогах, обставинах та припущеннях під час розробки проєкту. Зазначено, що у  методології Agile, проєктний цикл складається з ітеративних етапів, які зазвичай включають такі основні фази: планування, виконання, перевірку / оцінку, огляд та ретроспективу. Визначено та охарактеризовано основні складові Agile-проєкту, зокрема: product backlog (беклог продукту), спринти (sprints), sprint backlog (беклог спринту), dailystand-ups (щоденні зустрічі), sprin treview (ревью спринту), sprint retrospective (ретроспектива спринту).
نظرية حق الام او فلسفة التاريخ عند باخو فن
Authors: الحيدري ابراهيم محمد
Published: March 2024

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الشهادة قيمة روحية واجتماعية عليا
Authors: الحسن احسان محمد
Published: March 2024

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قراءة جديدة في الشعر الأموي
Authors: القيسي نوري حمودي
Published: March 2024

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اختيار الفئات في خرائط التظليل
Authors: اسود فلاح شاكر , البياتي صبري مصطفى
Published: March 2024

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تقييم دور المناطق الخضراء في التأثير على المناخ المحلي لمدينة كربلاء
Authors: ابو رحيل عبد الحسن مدفون
Published: March 2024

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العرب في الساحل الشرقي للخليج العربي ودورهم حتى القرن الرابع الهجري
Authors: عبد الكريم العاني عبد الرحمن
Published: March 2024

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حول كتابة تاريخ العرب في اوربا
Authors: عبود التكريتي نافع توفيق
Published: March 2024

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فن المسرحية و الملحمة عند الأغريق
Authors: التكريتي ناجي
Published: March 2024

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الذاكرة : نماذجها الكلاسيكية والحديثة .
Authors: حسين صالح قاسم
Published: March 2024

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اللغة في شعر أبي إسحاق إبراهيم الألبيري
Authors: محمود خلف نافع
Published: March 2024

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التحليل الجيومورفولوجي لبحيرة شاري
Authors: نافع شاكر سحر
Published: March 2024

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قراءة نقدية في شعر ابن هاني
Authors: محمود خلف نافع
Published: March 2024

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أصداء العلاقات العراقية - الإيرانية في الصفحات العراقية (14 تموز 1958 - النحاس |8 شباط 1963)
Authors: النحاس وائل علي أحمد
Published: March 2024

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الإيمان بتطوير المرأة الريفية
Authors: احمد الحميري أزهار
Published: March 2024

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المناخ في وصف الأصطخري
Authors: حسن محمد عباس
Published: March 2024

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الفنون الزخرفية العربية الإسلامية في الوطن العربي
Authors: العبيدي صلاح حسين
Published: March 2024

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النبر في اللغة العربية
Authors: محسن ولاء صادق
Published: March 2024

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ثورة ۱۸۵۷ وتأثيرها على أوضاع الهند
Authors: المشهداني انتصارعلي عبد نجم
Published: March 2024

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الموازنة المائية المناخية ودليل الانزعاج خلال فصل الشتاء البعض المحطات المناخية في العراق
Authors: محمد طه رؤوف شیر , عبد الحسين أوراس غني
Published: March 2024

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اساليب الحدث في الرواية التاريخية العربية الجديدة
Authors: الزوبعي كريم يوسف علي
Published: March 2024

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الحاجات الاروائية لأراضي بحر النجف
Authors: السامرائي محمد جعفر
Published: March 2024

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الأصول التاريخية للخطا وتوسعاتهم العسكرية في تركستان ومنغوليا في العصر العباسي (513 - 533هـ)/(1119 - 1138م)
Authors: الطائي سعاد هادي حسن
Published: March 2024

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الوركاء (اوروك) حضارتها , بُنيتها , تخطيطها
Authors: الياسري حميد  ياسر , محمد صفاء جاسم
Published: March 2024

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اتجاهات المنهج النقدي عند الدكتور محمد غنيمي هلال ( دراسة في نقد النقد )
Authors: سعدون نادية هناوي
Published: March 2024

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فتح الأقفال بشرح تحفة الأطفال
Authors: صالح نهاد حسوبي
Published: March 2024

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فن الألوان والصباغة على المنسوجات خلال العصور الإسلامية
Authors: المختار فريال داود
Published: March 2024

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الحل الشعبي
Authors: فرج لمى علي
Published: March 2024

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تاثير الاختراق الثقافي في الواقع الاجتماعي
Authors: مهدي ماجدة شكر
Published: March 2024

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مقدمة في دراسة المسرح العربي
Authors: نصيف جميل
Published: March 2024

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بعض خصائص واتجاهات الهجرة من الارياف الى المدن في العراق
Authors: عزيز مكي محمد
Published: March 2024

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دراسة مقارنة النواحي الصوتية في كتاب العين والنضرية الحديثة في علم الصوت
Authors: الحماش خليل ابراهيم
Published: March 2024

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تورغيف بين هاملت ودون کیشوت
Authors: يونس محمد
Published: March 2024

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الحذف الصوتي في القرآن الكريم
Authors: عبد الحميد ليث أسعد
Published: March 2024

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أستخدامات المياه الجوفية في العراق في ضوء توزيعها المكاني
Authors: الزيدي فاروق محمد علي حسين
Published: March 2024

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علاقة الهطول: أمطار وثلوج مع التصريف النهري في أقاليم روافد حوض دجلة للمدة 1941 – 1980
Authors: القشطيني باسل إحسان
Published: March 2024

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بعض مؤشرات الحرمان في ميدان التعليم في العراق (دراسة استطلاعية)
Authors: حمزة كريم محمد
Published: March 2024

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البداوة والحضارة في القران الكريم
Authors: الشماع صالح
Published: March 2024

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اقتصاديات صيانة الموارد النفطية
Authors: القيسي حميد
Published: March 2024

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الانسان ومصادر البيئة الاقتصادية
Authors: البرازي نوري خليل
Published: March 2024

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مصادر الادب العباسي
Authors: الزبيدي علي
Published: March 2024

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The Study on Key Changes and Prospects in North Korean Constitution and Science & Technology Legislation: Focusing on the Constitution and Science and Technology Law
Authors:   Korea Society of Unification & North Korean Law Studies(North Korean Law Society), Shin Yu-lee
Published: March 2024

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