Journal articles: 'Metallurgy and Metallic Materials'

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Zinigrad, Michael, and Konstantin Borodianskiy. "Welding, Joining, and Coating of Metallic Materials." Materials 13, no. 11 (June 10, 2020): 2640. http://dx.doi.org/10.3390/ma13112640.

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Welding, joining, and coating of metallic materials are among the most applicable fabrication processes in modern metallurgy. Welding or joining is the manufacture of a metal one-body workpiece from several pieces. Coating is the process of production of metallic substrate with required properties of the surface. A long list of specific techniques is studied during schooling and applied in industry; several include resistant spot, laser or friction welding, micro arc oxidation (MAO), chemical vapor deposition (CVD), and physical vapor deposition (PVD), among others. This Special Issue presents 21 recent developments in the field of welding, joining, and coating of various metallic materials namely, Ti and Mg alloys, different types of steel, intermetallics, and shape memory alloys.

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Ullmaier, H. "Radiation Damage in Metallic Materials." MRS Bulletin 22, no. 4 (April 1997): 14–21. http://dx.doi.org/10.1557/s088376940003298x.

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Radiation-damage research started with the installation of the first nuclear reactors in the United States. In 1946 Wigner pointed out that energetic neutrons would displace atoms from their regular lattice sites and thus change the properties of irradiated materials—a prediction that was soon confirmed experimentally. Most of these changes are unfavorable for the performance of materials, justifying the influence of radiation being referred to as “radiation damage.”Since radiation-induced materials degradation can have a drastic impact on the safe and economic operation of present fission reactors and, probably even more, on future fusion reactors, radiation-damage research comprised a large part of the research-and-development programs for nuclear materials. As a result of this effort, a broad database is now available, and materials have been developed that fulfill practically all requirements being encountered in present nuclear technology.Besides this applied work, extensive fundamental research on radiation effects has been carried out because physicists soon recognized that bombardment with energetic particles offered a unique method to create controlled populations of defects in solids. Whereas the cross-linking between basic and applied research was rather weak in the early stages, a convergence of the two branches has been clearly noticeable during the last decade. This welcome development occurred for a variety of reasons. Examples are the need to employ simulation irradiations in cases where no prototypic devices exist (fusion reactors, high-power spallation neutron sources) and the increasing application of ion-beam techniques in microelectronics, thin-film technology, and metallurgy where the damage produced by the implanted ions needs clarification.

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Juszczyk, B., J. Kulasa, W. Malec, Sz Malara, M. Czepelak, and L. Ciura. "Microstructure and Tribological Properties of the Copper Matrix Composite Materials Containing Lubricating Phase Particles." Archives of Metallurgy and Materials 59, no. 1 (March 1, 2014): 365–69. http://dx.doi.org/10.2478/amm-2014-0061.

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Abstract The paper presents results of the studies into influence of individual particles of lubricating phase on microstructure and tribological properties of copper based composite materials for slide bearings. The studied material was composed of copper alloys with lubricating phase particles, e.g. in a form of graphite and glassy carbon. The metallic matrix of composite materials consisted of Cu-Sn type alloys. Production of the examined materials included processes with complete or partial participation of liquid phase and was conducted in two ways. In production of composites both classical powder metallurgy technology was applied and a method of melting with simultaneous mechanical stirring in liquid state (stir casting). Particles of lubricating phases were heated up to the temperature of 200°C and introduced into a liquid metal and then stirring process at constant rate of 1500 rpm rotational speed was applied. To improve wettability of graphite and glassy carbon particles titanium was introduced into the metallic matrix. In production of the composites by powder metallurgy methods the process consisted of mixing of bronze powders and particles of non-metallic phases and then their consolidation. Both quantitative and qualitative structure analysis of the produced composites was performed. Also through evaluation of tribological properties (friction coefficient, wear) with CSM Instruments high temperature tribometer THT was conducted.

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Costoiu, Mihnea, Adrian Ioana, Augustin Semenescu, Dragos Marcu, and Massimo Polifroni. "Management elements for the spatial organization of enterprises from the metallic materials industry." MATEC Web of Conferences 178 (2018): 08009. http://dx.doi.org/10.1051/matecconf/201817808009.

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The spatial organization of enterprises is of great importance for the metallic materials industry (metallurgy), given the diversity and complexity of the technological processes and the related equipment. In an enterprise from the metallic materials industry, there may be sections for: production, casting, forging, mechanical (hot and / or cold) processing, assembly etc. for the different stages of the technological process related to the products to be made. The article presents theoretical and practical elements regarding the management of the spatial organization of enterprises in the metallic materials industry. The principles and methods of spatial organization are presented and analyzed. These principles and methods are based on the biunivocal relation between the functional and constructive changes related to the technologies and equipment (machinery, aggregates) specific to the metallic material industry. Prescribing (establishing) the objective function (OF) of the technological processes modeling system in the metallic materials industry is based on the qualitative - economic analysis of these processes.

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Yoon, Seung Chae, Do Minh Nghiep, Sun Ig Hong, Z. Horita, and Hyoung Seop Kim. "Achieving Both Powder Consolidation and Grain Refinement for Bulk Nanostructured Materials by Equal-Channel Angular Pressing." Key Engineering Materials 345-346 (August 2007): 173–76. http://dx.doi.org/10.4028/www.scientific.net/kem.345-346.173.

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Manufacturing bulk nanostructured materials with least grain growth from initial powders is challenging because of the bottle neck of bottom-up methods using the conventional powder metallurgy of compaction and sintering. In this study, bottom-up type powder metallurgy processing and top-down type SPD (Severe Plastic Deformation) approaches were combined in order to achieve both full density and grain refinement of metallic powders. ECAP (Equal-Channel Angular Pressing), one of the most promising processes in SPD, was used for the powder consolidation method. For understanding the ECAP process, investigating the powder density as well as internal stress, strain and strain rate distribution is crucial. We investigated the consolidation and plastic deformation of the metallic powders during ECAP using the finite element simulations. Almost independent behavior of powder densification in the entry channel and shear deformation in the main deformation zone was found by the finite element method in conjunction with a pressure dependent material yield model. Effects of processing parameters on densification and density distributions were investigated.

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Skrbek, Břetislav, and Vladimír Nosek. "Development and Implementation of Combined Structuroscopes for Dispersion Metallic Materials." Materials Science Forum 952 (April 2019): 339–45. http://dx.doi.org/10.4028/www.scientific.net/msf.952.339.

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Only some from series of non-destructive testing methods of material defects are employed for measurement of structural parameters of materials. The principle of acoustic and magnetic structuroscopy of cast irons and steel is explained. The examples of exploitation and equipment are described. At least two methods must be used simultaneously for strength and heat resistance measurement of composites, powder metallurgy products and cast irons. Development of this combined structuroscopy of cast irons. The equipment TELIT 3 was developed for evaluation of cast iron quality at critical sites of complicated castings (cylinder blocks of transport engines). The direction of furher research was indicated – exploitation of magnetic excited acoustic wave and combined structuroscopy of thin composite layers.

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Veillère, Amélie, Hiroki Kurita, Akira Kawasaki, Yongfeng Lu, Jean-Marc Heintz, and Jean-François Silvain. "Aluminum/Carbon Composites Materials Fabricated by the Powder Metallurgy Process." Materials 12, no. 24 (December 4, 2019): 4030. http://dx.doi.org/10.3390/ma12244030.

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Aluminum matrix composites reinforced with carbon fibers or diamond particles have been fabricated by a powder metallurgy process and characterized for thermal management applications. Al/C composite is a nonreactive system (absence of chemical reaction between the metallic matrix and the ceramic reinforcement) due to the presence of an alumina layer on the surface of the aluminum powder particles. In order to achieve fully dense materials and to enhance the thermo-mechanical properties of the Al/C composite materials, a semi-liquid method has been carried out with the addition of a small amount of Al-Si alloys in the Al matrix. Thermal conductivity and coefficient of thermal expansion were enhanced as compared with Al/C composites without Al-Si alloys and the experimental values were close to the ones predicted by analytical models.

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Torralba, Jose Manuel. "Powder Metallurgy: A New Open Section in Metals." Metals 11, no. 10 (September 24, 2021): 1519. http://dx.doi.org/10.3390/met11101519.

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Powder Metallurgy (PM) is a forming technology that uses metallic (sometimes also in conjunction with ceramic) powders to develop parts, most of the time through a thermal process called sintering, which never reaches the melting point of the principal component of the alloy [...]

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Zaitsev, Alexander I. "Prospective directions for development of metallurgy and materials science of steel." Pure and Applied Chemistry 89, no. 10 (September 26, 2017): 1553–65. http://dx.doi.org/10.1515/pac-2016-1129.

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AbstractThe features of current state of metallurgical technology and materials science of mass high-grade steels are viewed. A promising direction for principle improvement of the complex of properties and qualitative characteristics of steel including those, which are difficult to combine, is shown. It is the development of adequate physico-chemical methods of prediction and efficient technology methods of management of non-metallic inclusions, forms of presence of impurities, phases precipitations, structural state, including uniformity over the volume of metal. Additionally this approach allows reducing costs and expanding the raw material base. Its effectiveness is illustrated by the results of research carried out for a number of groups of mass high-quality steels.

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Loretto, M. H. "The value of microscopy in research in ceramic and metallic materials." Proceedings, annual meeting, Electron Microscopy Society of America 50, no. 1 (August 1992): 148–49. http://dx.doi.org/10.1017/s0424820100121144.

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This somewhat provocative symposium is scheduled to look at the (real) role of (transmission) electron microscopy in engineering materials. The very fact that the organisers have framed the title in this way, implies that there is a school of thought that questions the value of transmission electron microscopy (TEM) in areas other than in academic research - and perhaps even its value in academic research! Hence the aim of this paper is to assess whether TEM has made a contribution to the understanding, and thus to the successful application, of engineering materials or whether, as with so much physical metallurgy, it has simply confirmed what was already known to the practitioner for many years.

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Knaislová, Anna, Pavel Novák, Jaromír Kopeček, and Filip Průša. "Properties Comparison of Ti-Al-Si Alloys Produced by Various Metallurgy Methods." Materials 12, no. 19 (September 21, 2019): 3084. http://dx.doi.org/10.3390/ma12193084.

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Melting metallurgy is still the most frequently used and simplest method for the processing of metallic materials. Some of the materials (especially intermetallics) are very difficult to prepare by this method due to the high melting points, poor fluidity, or formation of cracks and pores after casting. This article describes the processing of Ti-Al-Si alloys by arc melting, and shows the microstructure, phase composition, hardness, fracture toughness, and compression tests of these alloys. These results are compared with the same alloys prepared by powder metallurgy by the means of a combination of mechanical alloying and spark plasma sintering. Ti-Al-Si alloys processed by melting metallurgy are characterized by a very coarse structure with central porosity. The phase composition is formed by titanium aluminides and titanium silicides, which are full of cracks. Ti-Al-Si alloys processed by the powder metallurgy route have a relatively homogeneous fine-grained structure with higher hardness. However, these alloys are very brittle. On the other hand, the fracture toughness of arc-melted samples is immeasurable using Palmqvist’s method because the crack is stopped by a large area of titanium aluminide matrix.

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Morcali, M. H. "Development of a method for determination of metallic iron content within hot briquette iron (HBI) for steelmaking." Journal of Mining and Metallurgy, Section B: Metallurgy 52, no. 2 (2016): 151–55. http://dx.doi.org/10.2298/jmmb150606017m.

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The growing use of metallic iron in metallurgy and industrial chemical applications requires a fast, easy and cheap method for the determination of metallic iron, not merely in recyclable materials, such as iron pellets, reduced iron mill scale dust, electric arc furnace dust and pig iron, but from hot briquette iron (HBI) as well. This study investigates a new method for determination of metallic iron within HBI used for steel-making materials. The effects of reaction time, temperature, and stirring rate were studied. The concentration of iron was determined via Atomic Absorption Spectroscopy (AAS). After the optimization study, high-purity metallic iron powder (Sigma-Aldrich, PubChem Substance ID 24855469) was used to compare efficiencies and identify the optimum conditions; The present study was matched with international standard methods (BS ISO 5416:2006, IS 15774:2007). Results were consistent with certified values and metallic iron content could be determined within the 95% confidence level. The purposed method is easy, straightforward, and cheap.

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Confalonieri, Chiara, and Elisabetta Gariboldi. "Effect of Different Production Processes on Metallic Composite Phase Change Materials for Thermal Energy Storage." Materials Science Forum 1016 (January 2021): 359–65. http://dx.doi.org/10.4028/www.scientific.net/msf.1016.359.

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Phase Change Materials (PCMs) can be applied in Thermal Energy Storage and Thermal Management systems, exploiting the storage and release of latent heat associated to a phase transition. Among them, metallic PCMs can be used at medium and high temperatures (i.e. above 150°C), storing higher heat per unit volume at higher temperatures with respect to the most widely investigated polymeric and salt-based PCMs. Miscibility Gap Alloys (MGAs) can be used to obtain multiple-phase mixtures in which the active phase (the actual PCM) is mixed to a second, high-melting temperature phase, with negligible interaction between them. These can actually be considered as fully metallic composite materials specifically developed for thermal management. Suitable microstructures can prevent leakage of active phase when the solid-liquid transition occurs, resulting in a form-stable PCM (FS-PCM). However, obtaining these microstructures it is not trivial. The present study focuses on a solid-liquid FS-PCM consisting of a ‘classical’ fully metallic FS-PCM, an Al-Sn based MGAs produced by powder metallurgy. The goal was to evaluate the effect of different production processes on thermal and mechanical behaviour of the PCM. Particularly, powder metallurgy routes including both simple mixing and ball milling were compared and further combined. Moreover, several compression and sintering conditions were considered, also substituting Al powders with Al-alloy powders, in order to optimize the material microstructures in view of suitable thermal and mechanical properties. Finally, the casting route with a rapid solidification approach was investigated for the same alloy.

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Zhang, Lian Zhong, and Jing Min Li. "The Application of Ultrasonic Technology in the Hard, Brittle Materials Processing Research." Advanced Materials Research 538-541 (June 2012): 1387–92. http://dx.doi.org/10.4028/www.scientific.net/amr.538-541.1387.

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The ultrasonic processing to sometimes also call that a Ultrasonic machining, it can not only processing cemented carbide, hardened steel, and other hard-brittle metal materials, and better Co-processing in glass, ceramics, germanium semiconductor, marble, a non-conducting silicon, and other hard-brittle non-metallic materials, but also can be used in cleaning, welding, testing, measurement, metallurgy and other aspects of this paper to study the principles of ultrasonic processing and The application of ultrasound to explore Development, the modern processing technology of the latest trends.

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Timofeev, A. N., and A. I. Logacheva. "FROM METALLURGY OF GRANULES TO ADDITIVE TECHNOLOGIES." Izvestiya Vuzov Tsvetnaya Metallurgiya (Proceedings of Higher Schools Nonferrous Metallurgy, no. 3 (June 14, 2018): 84–94. http://dx.doi.org/10.17073/0021-3438-2018-3-84-94.

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OJSC «Kompozit» traces its history back to the Central Research Institute of Materials Science (CRIMS) and successfully acts as a leading material science institute in the rocket and space industry up to the present day. The enterprise uses and improves state-of-theart technologies, and creates a variety of new metal, non-metallic, composite and ceramic materials. This article provides an overview of powder sector development from the metallurgy of granules to additive technologies and shows the participation of MISIS graduates. The experience of OJSC «Kompozit» in the manufacturing of parts by selective electron beam melting (SEBM) of home-made VT6S titanium alloy powders. Initial powders are obtained by plasma centrifugal spraying of the bar stock. It is shown that the powders feature an ideal spherical shape, low defect rate, high processability and fully meet the process requirements. The microstructure and properties of samples and parts obtained by the SEBM are studied.

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Monchoux, Jean-Philippe, Alain Couret, Lise Durand, Thomas Voisin, Zofia Trzaska, and Marc Thomas. "Elaboration of Metallic Materials by SPS: Processing, Microstructures, Properties, and Shaping." Metals 11, no. 2 (February 12, 2021): 322. http://dx.doi.org/10.3390/met11020322.

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After a few decades of increasing interest, spark plasma sintering (SPS) has now become a mature powder metallurgy technique, which allows assessing its performances toward fabricating enhanced materials. Here, the case of metals and alloys will be presented. The main advantage of SPS lies in its rapid heating capability enabled by the application of high intensity electric currents to a metallic powder. This presents numerous advantages balanced by some limitations that will be addressed in this review. The first section will be devoted to sintering issues, with an emphasis on the effect of the electric current on the densification mechanisms. Then, typical as-SPS microstructures and properties will be presented. In some cases, they will be compared with that of materials processed by conventional techniques. As such, examples of nanostructured materials, intermetallics, metallic glasses, and high entropy alloys, will be presented. Finally, the implementation of SPS as a technique to manufacture complex, near-net shape industrial parts will be discussed.

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Gallino, Isabella, and Ralf Busch. "Metallurgy Beyond Iron." Publications of the Astronomical Society of Australia 26, no. 3 (2009): iii—vii. http://dx.doi.org/10.1071/as08073.

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AbstractMetallurgy is one of the oldest sciences. Its history can be traced back to 6000 BCE with the discovery of Gold, and each new discovery — Copper, Silver, Lead, Tin, Iron and Mercury — marked the beginning of a new era of civilization. Currently there are 86 known metals, but until the end of the 17th century, only 12 of these were known. Steel (Fe–C alloy) was discovered in the 11th century BCE; however, it took until 1709 CE before we mastered the smelting of pig-iron by using coke instead of charcoal and started the industrial revolution. The metallurgy of nowadays is mainly about discovering better materials with superior properties to fulfil the increasing demand of the global market. Promising are the Glassy Metals or Bulk Metallic Glasses (BMGs) — discovered at first in the late 50s at the California Institute of Technology — which are several times stronger than the best industrial steels and 10-times springier. The unusual structure that lacks crystalline grains makes BMGs so promising. They have a liquid-like structure that means they melt at lower temperatures, can be moulded nearly as easily as plastics, and can be shaped into features just 10 nm across. The best BMG formers are based on Zr, Pd, Pt, Ca, Au and, recently discovered, also Fe. They have typically three to five components with large atomic size mismatch and a composition close to a deep eutectic. Packing in such liquids is very dense, with a low content of free volume, resulting in viscosities that are several orders of magnitude higher than in pure metal melts.

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Seramak, Tomasz, Waldemar Serbiński, and Andrzej Zieliński. "Formation of Porous Structure of the Metallic Materials Used on Bone Implants." Solid State Phenomena 183 (December 2011): 155–62. http://dx.doi.org/10.4028/www.scientific.net/ssp.183.155.

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Research on improvement of structure and fabrication methods of the bone implants are carried out for many years. Research are aimed to shape the structures, that will have a Young's modulus value similar to the value of the human bones Young's modulus. Depending on the porosity, Young’s moduli can even be tailored to match the modulus of bone closer than solid metals can, thus reducing the problems associated with stress shielding of a human bones. The designed structure should also be characterized by a high abrasion and corrosion resistance to and allow bone ingrowth in the implant material to make the best bone-implant fixation. For this purpose, implants should have a porous structure with an appropriate pore size and with open-cell porosity. Material for bone implants must also have a high biocompatibility and bioactivity. Following these requirements, the metallic porous materials appear to be the most suitable material for bone implants. In this paper a various methods of a porous materials fabrication for bone implants are listed. It was shown that titanium and its alloys (e.g. Ti6Al4V or Ti13Nb13Zr) are widely used as biomaterials for implants. Research in order to increase their wear and corrosion resistance and to improve their biocompatibility and bioactivity are still carried out. One of the most effective methods of manufacturing the porous materials is a powder metallurgy (PM). In this paper the results of research under shaping the structure of the porous titanium alloy Ti13Nb13Zr are also presented. As a manufacturing method of the porous material from the investigated and mentioned above Ti alloy, the powder metallurgy (PM) was choosen - with and without the use of a space holders. Method of fabrication a spherical powder from the aforementioned Ti alloy and results of its morphology research are discussed. The applied powder compaction method (with use and without use of space holders) and the influence of a sintering process on the final microstructure morphology of porous material obtained from Ti13Nb13Zr alloy are also presented and discussed.

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Popescu, Ileana Nicoleta, Ruxandra Vidu, and Vasile Bratu. "Porous Metallic Biomaterials Processing (Review) Part 1: Compaction, Sintering Behavior, Properties and Medical Applications." Scientific Bulletin of Valahia University - Materials and Mechanics 15, no. 13 (October 1, 2017): 28–40. http://dx.doi.org/10.1515/bsmm-2017-0015.

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AbstractOver the last few decades, researchers has been focused on the study of processing using different methods of new biocompatible and/or biodegradable materials such as permanent or temporary medical implants in reconstructive surgery. The advantages of obtaining biomedical implants by Powder Metallurgy (P/M) techniques are (i) obtaining the near-net-shaped with complex forms, (ii) making materials with controlled porosity or (iii) making mechanically resistant sintered metallic materials used as reinforcing elements for ceramic/polymeric biocompatible materials. In this first part of the 2-part review, the most used and newest metallic biomaterials obtained by P/M methods are presented, along with their compaction and sintering behavior and the properties of the porous biomaterials studied in correlation with the biomedical domain of application.

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Rota, A., T. V. Duong, and T. Hartwig. "Micro powder metallurgy for the replicative production of metallic microstructures." Microsystem Technologies 8, no. 4-5 (August 1, 2002): 323–25. http://dx.doi.org/10.1007/s00542-002-0157-y.

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Yoon, Seung Chae, and Hyoung Seop Kim. "Equal Channel Angular Pressing of Metallic Powders for Nanostructured Materials." Materials Science Forum 503-504 (January 2006): 221–26. http://dx.doi.org/10.4028/www.scientific.net/msf.503-504.221.

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In this study, bottom-up type powder processing and top-down type SPD (severe plastic deformation) approaches were combined in order to achieve both full density and grain refinement of metallic powders with least grain growth, which was considered as a bottle neck of the bottom-up method using the conventional powder metallurgy of compaction and sintering. ECAP (Equal channel angular pressing), one of the most promising method in SPD, was used for the powder consolidation. In the ECAP process of not only solid but also powder metals, knowledge of the density as well as internal stress, strain and strain rate distribution is important for understanding the process. We investigated the consolidation, plastic deformation and microstructure evolution behavior of the metallic powders during ECAP using experimental and theoretical methods. Almost independent behavior of powder densification in the entry channel and shear deformation in the main deformation zone was found by the finite element method in conjunction with a pressure dependent material yield model. It was found that high mechanical strength could be achieved effectively as a result of the well bonded powder contact surface during ECAP process of gas atomized Al-Si powders. The SPD processing of powders is a viable method to achieve both fully density and nanostructured materials.

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Csáki, Ioana, Petru Moldovan, and Gabriela Popescu. "Powder Metallurgy Processing of Al/TiAl₃+Al₂O₃." Materials Science Forum 672 (January 2011): 215–18. http://dx.doi.org/10.4028/www.scientific.net/msf.672.215.

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This paper aims to present a way of obtaining aluminum based composite material obtained by powder metallurgy technique. We start mixing and milling the powders, compressing and sintering the samples. We established a sintering cycle for this type of composite material and studied obtained samples by SEM microscopy. The reaction between the matrix and the precursor of the reinforcing materials was studied with the aid of HSC 4.0 program, available at Engineering and Management of Metallic Materials department.

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Dudina, Dina V., Boris B. Bokhonov, Igor S. Batraev, Vyacheslav I. Kvashnin, Mikhail A. Legan, Aleksey N. Novoselov, Alexander G. Anisimov, et al. "Microstructure and Mechanical Properties of Composites Obtained by Spark Plasma Sintering of Al–Fe66Cr10Nb5B19 Metallic Glass Powder Mixtures." Metals 11, no. 9 (September 15, 2021): 1457. http://dx.doi.org/10.3390/met11091457.

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At present, metallic glasses are evaluated as alternative reinforcements for aluminum matrix composites. These composites are produced by powder metallurgy via consolidation of metallic glass-aluminum powder mixtures. In most studies, the goal has been to preserve the glassy state of the reinforcement during consolidation. However, it is also of interest to track the structure evolution of these composites when partial interaction between the matrix and the metallic glass is allowed during sintering of the mixtures. The present work was aimed to study the microstructure and mechanical properties of composites obtained by spark plasma sintering (SPS) of Al-20 vol.% Fe66Cr10Nb5B19 metallic glass mixtures and compare the materials, in which no significant interaction between the matrix and the Fe-based alloy occurred, with those featuring reaction product layers of different thicknesses. Composite materials were consolidated by SPS at 540 and 570 °C. The microstructure and mechanical properties of composites obtained by SPS and SPS followed by forging, composites with layers of interfacial reaction products of different thicknesses, and metallic glass-free sintered aluminum were comparatively analyzed to conclude on the influence of the microstructural features of the composites on their strength.

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Zhang, D. L., C. C. Koch, and R. O. Scattergood. "The role of new particle surfaces in synthesizing bulk nanostructured metallic materials by powder metallurgy." Materials Science and Engineering: A 516, no. 1-2 (August 2009): 270–75. http://dx.doi.org/10.1016/j.msea.2009.03.024.

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Gauthier, Maxime, Louis-Philippe Lefebvre, Yannig Thomas, and Martin N. Bureau. "Production of Metallic Foams Having Open Porosity Using a Powder Metallurgy Approach." Materials and Manufacturing Processes 19, no. 5 (October 2004): 793–811. http://dx.doi.org/10.1081/amp-200030539.

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Ameyama, Kei, Sanjay Kumar Vajpai, and Mie Ota. "Microstructure Evolution and Deformation Mechanisms of Harmonic Structure Designed Materials." Materials Science Forum 879 (November 2016): 145–50. http://dx.doi.org/10.4028/www.scientific.net/msf.879.145.

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This paper presents the novel microstructure design, called Harmonic Structure, which gives structural metallic materials outstanding mechanical properties through an innovative powder metallurgy process. Homogeneous and ultra-fine grain (UFG) structure enables the materials high strength. However, such a “Homo-“ and “UFG” microstructure does not, usually, satisfy the need to be both strong and ductile, due to the plastic instability in the early stage of the deformation. As opposed to such a “Homo-and UFG“ microstructure, “Harmonic Structure” has a heterogeneous microstructure consisting of bimodal grain size together with a controlled and specific topological distribution of fine and coarse grains. In other words, the harmonic structure is heterogeneous on micro-but homogeneous on macro-scales. In the present work, the harmonic structure design has been applied to pure metals and alloys via a powder metallurgy route consisting of controlled severe plastic deformation of the corresponding powders by mechanical milling or high pressure gas milling, and subsequent consolidation by SPS. At a macro-scale, the harmonic structure materials exhibited superior combination of strength and ductility as compared to their homogeneous microstructure counterparts. This behavior was essentially related to the ability of the harmonic structure to promote the uniform distribution of strain during plastic deformation, leading to improved mechanical properties by avoiding or delaying localized plastic instability.

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Aranda, Rosa María, Fátima Ternero, Sergio Lozano-Pérez, Juan Manuel Montes, and Francisco G. Cuevas. "Capacitor Electrical Discharge Consolidation of Metallic Powders—A Review." Metals 11, no. 4 (April 11, 2021): 616. http://dx.doi.org/10.3390/met11040616.

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Manufacturing metallic materials from elemental or alloyed powders is an option in many industrial processes. Nevertheless, the traditional powder metallurgy processing including furnace sintering is at times detrimental for the microstructure attained in the powders. Alternative sintering processes based on the use of electricity and the energy obtained by the Joule effect in powder particles can be quick enough to avoid microstructural changes. In particular, when the energy is stored in a capacitor and then discharged, the heating process is extremely quick, lasting milliseconds or even microseconds. This process, generally known as electrical discharge consolidation, has been applied to a wide variety of metallic materials, easily preserving the original microstructure of the powders. Both porous or homogeneous and highly densified material can be obtained, and without losing the desired properties of the consolidated material. A general overview of the process and applications, as well as the results obtained by different research groups around the world, have been reviewed in this manuscript.

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Rigo, E. C. S., M. C. Bottino, B. D. Carraro, Elisa B. Taddei, Vinicius André Rodrigues Henriques, Cosme Roberto Moreira Silva, Ana Helena A. Bressiani, and José Carlos Bressiani. "Biomimetic Coatings on Ti-Based Alloys Obtained by Powder Metallurgy for Biomedical Applications." Materials Science Forum 530-531 (November 2006): 599–604. http://dx.doi.org/10.4028/www.scientific.net/msf.530-531.599.

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Comparing to hydroxyapatite (HA), which forms a strong chemical bond with the bony tissues, metallic materials are not able to bond with bone. For this reason, a great variety of complex coating methods, such as pulse-laser deposition, ion-beam assisted deposition and plasma-spray has been used to form a HA layer onto metallic surfaces. This study evaluated the performance of the biomimetic technique on apatite-based coating formation on two Tialloys. Ti-13Nb-13Zr and Ti-35Nb-7Zr-5Ta were obtained via powder metallurgy. The Tibased alloys were biomimetically coated using a technique which was modified from the conventional ones using a sodium silicate solution as the nucleant agent. Both alloys presented similar behavior in the evaluated conditions which means the formation of a homogeneous and well defined HA coating. These results show that these new non-toxic Tialloys seem to be very promising for biomedical applications.

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Abdullah, Noorsyakirah, Mohd Afian Omar, Shamsul Baharin Jamaludin, Nurazilah Mohd Zainon, Norazlan Roslani, Bakar Meh, Mohd Nizam Abd Jalil, Mohd Bakri Mohd Hijazi, and Ahmad Zahid Omar. "Innovative Metal Injection Molding (MIM) Method for Producing CoCrMo Alloy Metallic Prosthesis for Orthopedic Applications." Advanced Materials Research 879 (January 2014): 102–6. http://dx.doi.org/10.4028/www.scientific.net/amr.879.102.

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Powder injection molding (PIM) is a powder metallurgy process currently used for the production of complicated and near net shape parts of high performance materials [. This technique basically combines the advantages of plastic injection molding and the versatility of the conventional powder metallurgy technique. The process overcomes the shape limitation of powder compaction, the cost of machining, the productivity limits of isostatic pressing and slip casting, and the defect and tolerance limitations of conventional casting [1, 2, . According to German and Bose [, the technology of metal injection molding (MIM) is more complicated than that of the plastic injection molding, which arises from the need to remove the binder and to densify and strengthen the part. The process composed of four sequential steps: mixing of the powder and organic binder, injection molding, debinding where all binders are removed and sintering [1, 2, 3, 4]. If it necessary, secondary operations such as heat treatments after sintering can be performed [1, 2, 3, 4, .

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Wang, Rui Hua, Yao Qi Li, Si Yuan Yu, Xiu Qin Wang, Jie Guang Song, Chao Yang, Da Ming Du, Fang Wang, and Shi Bin Li. "Densification Mechanism of Al₂O₃/Al Metallic Ceramics Prepared via Powder Metallurgy Method." Key Engineering Materials 726 (January 2017): 189–93. http://dx.doi.org/10.4028/www.scientific.net/kem.726.189.

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Alumina ceramics with good mechanical and corrosion resistance, is one of the most widely used engineering ceramics. The aluminum has a high strength, high conductivity, high plasticity, etc. than aluminum ceramics used in more and more industries. In this paper, aluminum and alumina powder as raw material, mixing, forming, sintering and a series of processes for preparing the alumina/aluminum metallic ceramic materials, through performance testing and analysis can be found in the ratio of raw materials 50wt% Al, 50wt % Al2O3 relatively good moldability. After sintering, after measuring the density contrast is found better density in the pressing process pressure of 20MPa and holding pressure time for 20min. By comparing the sintering process, after the interface structure by scanning electron microscopy and found help improve density through the secondary sintering metallic ceramic materials.

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Lee, Pee-Yew, Sung-Ting Chung, Chung-Kwei Lin, Wen-Ta Tsai, and Hong-Ming Lin. "Preparation and Characterization of Dual-Phase Bulk Metallic Glasses through Powder Metallurgy Route." MATERIALS TRANSACTIONS 48, no. 7 (2007): 1595–99. http://dx.doi.org/10.2320/matertrans.mj200791.

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32

Zhao, Qinyang, Fei Yang, Rob Torrens, and Leandro Bolzoni. "Comparison of the Cracking Behavior of Powder Metallurgy and Ingot Metallurgy Ti-5Al-5Mo-5V-3Cr Alloys during Hot Deformation." Materials 12, no. 3 (February 1, 2019): 457. http://dx.doi.org/10.3390/ma12030457.

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The hot workability of metallic materials is significantly dependent on its ability to form plastic without cracking and fracturing. In this work, the cracking behavior of powder metallurgy (PM) Ti-5Al-5Mo-5V-3Cr (Ti-5553) alloy, consolidated from powder mixture, at a deformation temperature range of 600 °C–850 °C and strain rate of 0.1 s−1–10 s−1, was investigated through isothermal compression tests. The cracking behavior of the as-cast ingot metallurgy (IM) Ti-5553 alloy, at a deformation temperature of 700 °C was also investigated for comparison. Results suggested that the PM Ti-5553 alloy had a better hot workability, with a larger cracking-free processing window, and a lower deformation resistance than the IM counterpart. 45° shear fracture occurred in the PM alloy, compressed at the condition of 600 °C/10 s−1, and edge cracking was observed at the 700 °C/10 s−1. 45° shear fracture was also significant in the IM alloy specimen tested at 700 °C/10 s−1, and all the other IM alloy specimens compressed at 700 °C displayed longitudinal cracking. Moreover, the microscopic cracking observation showed that ductile dimple cracking can be found in the IM alloy, but brittle cleavage fracture was dominant in the cracking surface of PM alloy with a relatively low cracking ductility.

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Tan, Koon Tatt, Norhamidi Muhamad, Andanastuti Muchtar, Abu Bakar Sulong, and Yih Shia Kok. "Production of Porous Stainless Steel using the Space Holder Method." Sains Malaysiana 50, no. 2 (February 28, 2021): 507–14. http://dx.doi.org/10.17576/jsm-2021-5002-21.

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Metallic foams and porous materials can be produced by various methods. Among the methods that can produce metallic foams and porous materials, powder metallurgy is a promising method. This study investigates the production of a porous stainless steel by the space holder method in powder metallurgy. A novel space holder i.e. glycine and binder consisting of polymethylmethacrylate and stearic acid are used. Different amounts of glycine are added to the mixture of stainless-steel powder and binder. Subsequently, each mixture is cold-pressed at a pressure of 9-ton m-2. The samples are sintered at 1050 and 1150 °C with holding times of 30, 60, and 90 min. The microstructures and physical and mechanical properties of the sintered samples are investigated. A porous stainless steel with porosity ranging from 30.8 to 51.4% is successfully fabricated. Results show that the glycine content and sintering parameters influence the properties of the porous stainless steel. The sintering temperature significantly affects volumetric shrinkage. Volumetric shrinkage decreases as the volume fraction of glycine increases to 30% whereas sintering temperature 1150 °C and holding time 90 min will increase the volumetric shrinkage. The compressive yield strength and corresponding elastic modulus are in the ranges of 22.9 to 57.6 MPa and 6.3 to 26.8 GPa, respectively. The samples produced have potential biomedical applications because their mechanical properties, yield strength and elastic modulus match those of human bones.

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Zhang, X. Q., W. Wang, E. Ma, and J. Xu. "Refractory Mo–Si-Based Glassy Alloy Designed for Ultrahigh Strength and Thermal Stability." Journal of Materials Research 20, no. 11 (November 2005): 2910–13. http://dx.doi.org/10.1557/jmr.2005.0372.

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Mechanically alloyed Mo44Si26Ta5Zr5Fe3Co12Y5 multicomponent glassy alloy exhibits an exceptionally high glass transition temperature of 1202 K and a crystallization temperature of 1324 K, as well as an ultrahigh hardness of 18 GPa. This example is used to demonstrate metallic glasses that possess extraordinary thermal stability and ultrahigh strength and, at the same time, a wide supercooled liquid region (122 K) that is needed for processing into bulk forms through powder metallurgy routes.

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Gallego Parra, Samuel, Mihai Alin Pop, Tibor Bedő, and Virgil Geamăn. "Thixoforming and Powder Metallurgy - A Comparative Study and Practical Case." Materials Science Forum 907 (September 2017): 193–97. http://dx.doi.org/10.4028/www.scientific.net/msf.907.193.

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Pistons are commonly made of a cast aluminum alloy for excellent and lightweight thermal conductivity. Thermal conductivity is the ability of a material to conduct and transfer heat. Aluminum expands when heated and proper clearance must be provided to maintain free piston movement in the cylinder bore. The piston transforms chemical energy of the burned fuel into a mechanical energy. For this reason, the pistons are submitted to a complex combination of thermal stresses and high temperature mechanical cycles. In this study both powder metallurgy (PM) and thixoforming techniques are used to process a metallic matrix composite (MMC) as a promising material for pistons. Aluminum as matrix and copper powder, to enhance thermal conductivity, and glass fiber, which increases Young’s modulus and a lower thermal expansion coefficient, as reinforcement, are obtained for this aim. The optical microscope images showed in this study are a clear example of the distribution of the glass fiber in the matrix. These results can be the basis for new researches to develop and to obtain materials for new advanced materials for pistons.

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Solay, Anand S., and B. Mohan. "Enhanced Hardness Property in the Development of Al-TiC Composites through P/M Techniques." Advanced Materials Research 548 (July 2012): 243–49. http://dx.doi.org/10.4028/www.scientific.net/amr.548.243.

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Powder Metallurgy is a continually and rapidly evolving technology, embracing most metallic and alloy materials with a variety of shapes. Weight percent of reinforcements and processing parameters plays a vital role in determining strength of the powder metallurgical parts. In this work, the effect of varying weight percent of particulate TiC reinforcement with elemental 6061 Aluminium alloy on mechanical properties of specimens processed through powder metallurgy has been investigated. Weight percent of TiC ranges from 1% to 10% and the specimens are compacted at 125 MPa and 175 MPa. With increase in the weight percent of TiC up to 5%, micro hardness and tensile strength value increases and there is a decrease in tensile strength value for a weight percent of 10 % TiC. Increase in compaction pressure from 125 MPa to 175 MPa, the density, hardness and tensile strength value increases.

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Olanipekun, Ayorinde Tayo, Nthabiseng Beauty Maledi, and Peter Madindwa Mashinini. "The synergy between powder metallurgy processes and welding of metallic alloy: a review." Powder Metallurgy 63, no. 4 (August 7, 2020): 254–67. http://dx.doi.org/10.1080/00325899.2020.1807712.

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Monteiro, Waldemar Alfredo, Juan Alfredo Guevara Carrió, Claudia R. da Silveira, Marcelo Carvalhal, and Terezinha J. Masson. "Low Temperature Effect in Electrical Properties of Sintered Copper-Nickel-Aluminum Alloys." Materials Science Forum 805 (September 2014): 694–99. http://dx.doi.org/10.4028/www.scientific.net/msf.805.694.

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The major effort of sintered metallic alloys (compression, homogenization and sintering of metallic powder) is the observation of the evolution of electrical conductivity, mechanical properties (microhardness tests) and microstructures changes after appropriate thermomechanical treatments with the use of copper-nickel-aluminum alloys as electric material. In this case, the purpose was to verify the possible changes in these materials when subjected at low temperatures. Samples of Cux%Niy%Alz%initially compressed, sintered and homogenized were characterized by optical metallography (microstructure) and mechanical strength (hardness Vickers) at room temperature. Data of x-ray diffraction of polycrystalline samples were collected with a conventional Difractometer. After this was made measurements of electrical properties (electrical conductivity) at low temperatures of samples obtained from precursors of high purity in powder form, for the study of the influence of powder metallurgy processes in physical properties of metallic alloys in this condition.

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İpek, Mediha, Tuba Yener, Gözde Ç. Efe, Ibrahim Altınsoy, Cuma Bindal, and Sakin Zeytin. "Rapid Synthesis of Metallic Reinforced in Situ Intermetallic Composites in Ti-Al-Nb System via Resistive Sintering." Open Chemistry 16, no. 1 (September 3, 2018): 869–75. http://dx.doi.org/10.1515/chem-2018-0095.

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AbstractIntermetallics are known as a group of materials that draws attention with their features such as ordered structure, high temperature resistance, high hardness and low density. In this paper, it is aimed to obtain intermetallic matrix composites and also to maintain some ductile Nb and Ti metallic phase by using 99.5% purity, 35-44 μm particle size titanium, niobium and aluminium powders in one step via recently developed powder metallurgy processing technique - Electric current activated/assisted sintering system (ECAS). In this way, metallic reinforced intermetallic matrix composites were produced. Dominant phases of TiAl3 and NbAl3 which were the first compounds formed between peritectic reaction of solid titanium, niobium and molten aluminum in Ti-Al-Nb system during 10, 30 and 90 s for 2000 A current and 1.5-2.0 voltage were detected by XRD and SEM-EDS analysis. Hardness values of the test samples were measured by Vickers indentation technique and it was detected that the hardnesses of intermetallic phases as 411 HVN whereas ductile metallic phase as 120 HVN.

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40

Abd, Osama Ibrahim. "Experimental analysis on metallic foams-a response surface methodology approach." International Journal of Engineering & Technology 4, no. 1 (January 18, 2015): 149. http://dx.doi.org/10.14419/ijet.v4i1.4033.

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This study aimed to fabricate metallic porous materials using powder metallurgy (PM) space-holder technique. In the PM route, Al powder was mixed with different ratios (7%, 10%, and 20%) and sizes (500 and 1000 μm) of sodium chloride granules as space-holder agent. The mixture was then compacted at different compacting pressures (150, 200, and 250 MPa) and then heated to 280 °C for sintering. Subsequently, sodium chloride granules were removed by dissolving in water to obtain the porous structure. Tests were performed on all porous Al specimens, and characteristics such as density and porosity were measured. A statistical approach was used to optimize processing parameters. ANOVA statistical tool was used to obtain the final evaluation of the most significant features, namely, relative density and porosity fraction.

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Azad, Abdul-Majeed. "Novel synthesis of high phase-purity Mg2SnO4 from metallic precursors via powder metallurgy route." Materials Research Bulletin 36, no. 3-4 (February 2001): 755–65. http://dx.doi.org/10.1016/s0025-5408(01)00533-5.

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Silva, José M., Ricardo A. Cláudio, A. Sousa e Brito, Carlos M. Branco, and Jim Byrne. "Characterization of Powder Metallurgy (PM) Nickel Base Superalloys for Aeronautical Applications." Materials Science Forum 514-516 (May 2006): 495–99. http://dx.doi.org/10.4028/www.scientific.net/msf.514-516.495.

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During the last decade, some major improvements have been achieved concerning the evaluation of new types of materials suitable for aeronautical components exposed to severe operational conditions, such as turbine disks. Due to their outstanding mechanical properties, nickel base superalloys assumed a preferential position when compared with other conventional metallic alloys, benefiting from both their superior fatigue strength and high temperature behaviour. However, these alloys evince a high sensibility concerning possible defects that can arise due to certain types of loading, such as porosities and cavities associated with creep-fatigue at high temperatures. The present paper compiles some experimental results obtained for two types of recent nickel base superalloys. Some fatigue tests were performed using two configurations of these materials: a set of Udimet 720Li specimens (CT geometry) and a set of RR1000 specimens (CN geometry). A maximum temperature of 650°C was considered in both types of materials. The mechanical properties of these alloys were inferred via typical FCGR parameters, such as da/dN vs K curves, complemented with detailed analyses of the cracking mechanisms based on SEM observations. Finally, some metallographic characterization tests were carried out in order to determine the average grain size of these PM alloys and to confirm the presence of important microstructural constituents that can influence the overall fatigue performance of these materials.

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Yeh, Tze Yang, and Kuo Yuan Peng. "Characterization of Simultaneously Gas Atomized Ti/TiC Composite Powders." Key Engineering Materials 704 (August 2016): 302–7. http://dx.doi.org/10.4028/www.scientific.net/kem.704.302.

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Metallic composite materials are mainly manufactured by powder metallurgy (PM) or casting, with reinforced ceramic particulates dispersed in a metal matrix. The current study presents an investigation with respect to simultaneously gas-atomized spherical Ti/TiC composite powders. Various analytical methods are used to characterize the gas-atomized Ti/TiC composite powders, including XRD, laser particle size analysis, flow rate tests, apparent density and tap density tests, SEM, and alike. The spherical Ti/TiC composite powders will be further laser sintered at the next stage to utilize mechanical properties testing.

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Nguyen, Tien Hiep, Y. Konyukhov, Nguyen Van Minh, D. Y. Karpenkov, V. V. Levina, G. Karunakaran, and A. G. Buchirina. "Magnetic Properties of Fe, Co and Ni Based Nanopowders Produced by Chemical-Metallurgy Method." Eurasian Chemico-Technological Journal 23, no. 1 (March 25, 2021): 3. http://dx.doi.org/10.18321/ectj1028.

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This research study describes the magnetic properties of Fe, Co and Ni metallic nanopowders (NPs) and their ternary nanocomposites (NCs), which can be used as fillers in radio-wave absorbing composite materials and coatings, as well as for magnetic protection of banknotes and security paper. The nanopowders were prepared by the chemical metallurgy method. The desired properties of Fe, Co and Ni NPs and NCs were achieved by co-precipitation, the addition of surfactants and changes in reduction temperature and time parameters. Magnetic measurements showed that all samples of pure metal NPs are semi-hard magnetic materials. The added surfactants have distinct effects on the dimensional and magnetic characteristics of Fe, Co and Ni NPs. Ni–Co–Fe NCs are also mainly semi-hard magnetic materials. Fine-tuning of their composition and chemical reduction temperatures allows controlling the values of Ms and Hc in large ranges from 49 to 197 A·m2/kg and from 4.7 to 60.6 kA/m, respectively.

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Wen, Cui'e, and Yun Cang Li. "A Newly Developed Biocompatible Titanium Alloy and its Scaffolding by Powder Metallurgy." Key Engineering Materials 520 (August 2012): 201–7. http://dx.doi.org/10.4028/www.scientific.net/kem.520.201.

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Titanium and some of its alloys have received considerable attention for biomedical applications in recent years due to their excellent biocompatibility, high corrosion resistance and relatively low elastic modulus when compared to other metallic implant materials such as Co-Cr alloys and stainless steels. However, these alloys can still suffer from inadequate biocompatibility; lack of biological fixation and biomechanical mismatch with the properties of bone in vivo. In this study, a new biocompatible Ti alloy, Ti4Ta4Sn, consisting of alpha and beta phases was fabricated and their mechanical properties were investigated. Moreover, the Ti alloy was scaffolded into a porous structure using powder metallurgy with an architecture and elastic modulus mimicking those of cancellous bone. Cell culture results indicated that the new porous Ti alloy scaffold possesses excellent in vitro biocompatibility.

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Lichy, P., V. Bednarova, and T. Elbel. "Casting Routes for Porous Metals Production." Archives of Foundry Engineering 12, no. 1 (January 1, 2012): 71–74. http://dx.doi.org/10.2478/v10266-012-0014-0.

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Casting Routes for Porous Metals Production The last decade has seen growing interest in professional public about applications of porous metallic materials. Porous metals represent a new type of materials with low densities, large specific surface, and novel physical and mechanical properties, characterized by low density and large specific surface. They are very suitable for specific applications due to good combination of physical and mechanical properties such as high specific strength and high energy absorption capability. Since the discovery of metal foams have been developed many methods and techniques of production in liquid, solid and gas phases. Condition for the use of metal foams - advanced materials with unique usability features, are inexpensive ways to manage their production. Mastering of production of metallic foams with defined structure and properties using gravity casting into sand or metallic foundry moulds will contribute to an expansion of the assortment produced in foundries by completely new type of material, which has unique service properties thanks to its structure, and which fulfils the current demanding ecological requirements. The aim of research conducted at the department of metallurgy and foundry of VSB-Technical University Ostrava is to verify the possibilities of production of metallic foams by conventional foundry processes, to study the process conditions and physical and mechanical properties of metal foam produced. Two procedures are used to create porous metal structures: Infiltration of liquid metal into the mold cavity filled with precursors or preforms and two stage investment casting.

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47

Jeong, H. G., and W. J. Kim. "Hardening by Crystallization During Superplastic Flow in a Powder-metallurgy-processed Zr65Al10Ni10Cu15 Glass Metallic Alloy." Journal of Materials Research 20, no. 6 (June 1, 2005): 1447–55. http://dx.doi.org/10.1557/jmr.2005.0185.

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The superplastic behavior of the Zr65Al10Ni10Cu15 glass metallic alloy produced by the powder metallurgy method was examined in the supercooled liquid region. A tensile elongation as large as 750% was obtained at 6.3 × 10−3 s−1 at 697 K. Large strain hardening took place during the course of deformation and systematic trend was observed in the hardening behavior. Plots of stress versus strain and strain rate versus stress at 697 K showed that Newtonian viscous flow governed the plastic flow until the onset of strain hardening. Microstructure and differential scanning calorimetry analyses as well as flow stress versus testing time curves provided consistent evidence that the strain hardening was induced by crystallization. Crystallization was enhanced in the gauge region (deformed region) as compared to the grip region (undeformed region). Crystallization is expected to decrease tensile ductility by decreasing the strain-rate-sensitivity value and increasing the degree of brittleness. Hardening by crystallization, however, can contribute to neck stability if crystallization is enhanced in the neck region. The strain hardening and plastic stability parameters were measured as a function of strain for different strain rates at 696 K. The strain hardening parameter remained highly positive until failure. Because of this, the neck stability parameter (I) could be I < 0 in the entire hardening region. The contribution of hardening by crystallization to neck stability was found to be much more significant than that by grain growth in the superplastic metallic alloys. Reducing the specimen heating-and-holding time was suggested to promote superplasticity deformation without delaying initiation of crystallization. The largest tensile strain in the hardening region where crystallization may be obtained at the strain rates and temperatures where crystallization rate is controlled to be the lowest while maintaining I ≤ 0 throughout deformation.

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Matuła, Izabela, Grzegorz Dercz, Maciej Zubko, Joanna Maszybrocka, Justyna Jurek-Suliga, Sylwia Golba, and Izabela Jendrzejewska. "Microstructure and Porosity Evolution of the Ti–35Zr Biomedical Alloy Produced by Elemental Powder Metallurgy." Materials 13, no. 20 (October 13, 2020): 4539. http://dx.doi.org/10.3390/ma13204539.

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In the present study, the structure and porosity of binary Ti–35Zr (wt.%) alloy were investigated, allowing to consider powder metallurgy as a production method for new metallic materials for potential medical applications. The porous Ti–Zr alloys were obtained by milling, cold isostatic pressing and sintering. The pressure during cold isostatic pressing was a changing parameter and was respectively 250, 500, 750 and 1000 MPa. The X-ray diffraction study revealed only the α phase, which corresponds to the Ti–Zr phase diagram. The microstructure of the Ti–35Zr was observed by optical microscopy and scanning electron microscopy. These observations revealed that the volume fraction of the pores decreased from over 20% to about 7% with increasing pressure during the cold isostatic pressing. The microhardness measurements showed changes from 137 HV0.5 to 225 HV0.5.

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Astacio, Raquel, Fátima Ternero, Jesús Cintas, Francisco G. Cuevas, and Juan Manuel Montes. "Medium-Frequency Electrical Resistance Sintering of Soft Magnetic Powder Metallurgy Iron Parts." Metals 11, no. 6 (June 21, 2021): 994. http://dx.doi.org/10.3390/met11060994.

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The fabrication of soft magnetic Fe parts by the medium-frequency electrical resistance sintering (MF-ERS) technique is studied in this paper. This consolidation technique involves the simultaneous application to metallic powders of pressure and heat, the latter coming from the Joule effect of a low-voltage and high-intensity electric current. Commercially pure iron powder was used in the consolidation experiences. The porosity distribution, microhardness, electrical resistivity and hysteresis curves of the final compacts were determined and analysed. The results obtained were compared both with those of compacts consolidated by the conventional powder metallurgy (PM) route of cold pressing and vacuum furnace sintering, and with fully dense compacts obtained by double cycle of cold pressing and furnace sintering in hydrogen atmosphere.

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Gobber, Federico Simone, Jana Bidulská, Alessandro Fais, Róbert Bidulský, and Marco Actis Grande. "Innovative Densification Process of a Fe-Cr-C Powder Metallurgy Steel." Metals 11, no. 4 (April 19, 2021): 665. http://dx.doi.org/10.3390/met11040665.

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In this study, the efficacy of an innovative ultra-fast sintering technique called electro-sinter-forging (ESF) was evaluated in the densification of Fe-Cr-C steel. Although ESF proved to be effective in densifying several different metallic materials and composites, it has not yet been applied to powder metallurgy Fe-Cr-C steels. Pre-alloyed Astaloy CrM powders have been ad-mixed with either graphite or graphene and then processed by ESF. By properly tuning the process parameters, final densities higher than 99% were obtained. Mechanical properties such as hardness and transverse rupture strength (TRS) were tested on samples produced by employing different process parameters and then submitted to different post-treatments (machining, heat treatment). A final transverse rupture strength up to 1340 ± 147 MPa was achieved after heat treatment, corresponding to a hardness of 852 ± 41 HV. The experimental characterization highlighted that porosity is the main factor affecting the samples’ mechanical resistance, correlating linearly with the transverse rupture strength. Conversely, it is not possible to establish a similar interdependency between hardness and mechanical resistance, since porosity has a higher effect on the final properties.

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Journal articles on the topic 'Metallurgy and Metallic Materials'

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