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NiTi Thin-Film Shape Memory Alloys and Their Industrial Application
Published in Chander Prakash, Sunpreet Singh, J. Paulo Davim, Advanced Manufacturing and Processing Technology, 2020
Ajit Behera, Patitapabana Parida, Aditya Kumar
Ni4Ti3 is not an equilibrium phase. It has been found that there is a large difference in the response of the stress–strain behavior due to the internal stress caused by the Ni4Ti3 precipitates [23]. The NiTi intermetallic compound melt phase is NiTi2. Low-phase intermetallic compounds have many attractive properties such as high hardness, high melting point, excellent chemical stability, and strong atomic bonding. NiTi2 has a complex, face-centered cubic structure with 96 atoms per unit cell (space group Fd3m). According to reports, due to the high concentration of titanium in the titanium-rich film, NiTi2 nucleation precipitated during the crystallization process and grew along the austenite grain boundaries.
Analysis of modern methods of surface modification of light metals using external energy sources
Published in Dmitrii Zaguliaev, Victor Gromov, Sergey Konovalov, Yurii Ivanov, Electron-Ion-Plasma Modification of a Hypoeutectoid Al-Si Alloy, 2020
Dmitrii Zaguliaev, Victor Gromov, Sergey Konovalov, Yurii Ivanov
When choosing structural materials, priority is given to materials based on intermetallic compounds. Intermetallic-based systems have unique properties, such as: low density, oxidation resistance, heat resistance, high specific strength and high melting point, which leads to their application in the automotive and aviation industries. In [93], the problem of creating protective coatings of the Ti—Al system on a substrate of technically pure VT1-0 grade titanium is considered. The coatings of the system under study were deposited on a titanium substrate by electron beam welding under various conditions. After coating, studies were carried out on the structure and mechanical properties of the samples. The research results showed that the microhardness of coatings is many times greater than the microhardness of a titanium substrate, and the wear resistance was also increased. Structural analysis showed that the electron beam current has a key influence on the structure and phase composition of the resulting coatings. Titanium and its alloys were not chosen as an object of research by chance, since it is of great importance for the aviation and aerospace industry. One of the areas of combined processing is a set of methods of plastic deformation of materials in order to improve the structure, and as a result, increase the mechanical characteristics of condensed matter.
Self-Lubricating Ceramic Matrix Composites
Published in Emad Omrani, Pradeep K. Rohatgi, Pradeep L. Menezes, Tribology and Applications of Self-Lubricating Materials, 2017
Emad Omrani, Pradeep K. Rohatgi, Pradeep L. Menezes
Intermetallic compounds are promising materials for several high-temperature application resistances, electronic devices, and magnets as structural or nonstructural materials (heat resistance, corrosion conductors). Ni3Al intermetallic compound has been extensively studied for structural applications, heat resistance, and corrosion resistance because of the low density (7.5 g/cm3), high melting points (1668 K), high thermal conductivity, as well as high corrosion and oxidation resistance at high temperatures [31]. These excellent properties have made Ni3Al as the attractive high-temperature structural material and the corrosion-resistant material for a range of engineering applications such as gas turbine hardware, high-temperature dies and molds, cutting tools, and heat-treatment fixtures [32]. It has a broad application prospect in the civil and military industrial field, especially for the field of tribology. However, polycrystalline Ni3Al intermetallic compounds show brittleness at room and elevated temperatures arising from an extrinsic environmental effect [33], which severely restricts the tribological property of the material.
Production of nanostructure Zr–ZrCr2–Cr composite via MA process and subsequent heat treatment
Published in Materials and Manufacturing Processes, 2020
J. Arasteh, G.H. Akbari, M.H. Khazaei Feizabad
Intermetallic compounds are a group of materials which their properties are between the properties of metals and ceramics.[1] The melting points of the intermetallic compounds are very high[2] which has caused the strength at high temperatures is high, and also, these compounds are stable in the corrosive and oxidizing environments.[3] ZrCr2 is a type of the intermetallic compound that has been widely utilized in recent years as a hydrogen storage and high-temperature structural materials.[4–6] It was necessary to be noted that the melting point of the ZrCr2 intermetallic compound is 1673°C.[7] There is just one intermetallic compound (ZrCr2) in the Zr–Cr alloy system.[7] The properties of the Zr–Cr alloys depended on the morphology, distribution, and size of the ZrCr2 intermetallic phase.
Thermophysical and ultrasonic properties of GdCu under the effect of temperature and pressure
Published in Phase Transitions, 2020
Dharmendra Kumar Pandey, Chandreshvar Prasad Yadav
The materials formed with the combination of metal atoms that differ in structure in comparison to constituent metals are called intermetallics. The light rare earth-copper intermetallics exhibit FeB-type structure while heavy rare earth intermetallics resemble CsCl-type structure [1]. The heavy rare earth intermetallic GdCu has CsCl structure at room temperature and it can be synthesized by the arc melting method with the combination of Gd and Cu in the same ratio [1–6]. In the past two decades, CsCl/B2 structured heavy rare-earth intermetallic compounds have a lot of attraction due to their superior elastic, thermal, electrical and magnetic properties in comparison to ordinary metals [7–13]. The common properties of heavy rare-earth intermetallics are excellent strength, ductility and corrosion resistance which make them unique for industrial applications. Using different theoretical approaches, the elastic/mechanical, thermophysical and ultrasonic properties of B2 structured YM (M: Cu, Zn, Ag, Rh) [7–11], AgRE (RE: Sc, Y, La-Lu) [12] and REZn (RE: Sc, Y) [13] intermetallics are reported in the literature.
Processing of duplex stainless steel by WEDM
Published in Materials and Manufacturing Processes, 2018
A. Pramanik, A. K. Basak, A. R. Dixit, S. Chattopadhyaya
The metallurgy of DSS is as follows, briefly: if heated to 1350°C and hold at this point, maximum of the austenite transforms to ferrite phase, and ferrite grains form. At cooling from 1350 to 800°C, the austenite phase precipitates all over the borders of ferrite grains. The ultimate structure is determined by the factors of thermal cycles, for example, topmost temperature, time of holding, and the rate of cooling.[28] Typically, very fast rate of cooling gives remarkably coarse grains of ferrite.[29] This is disadvantageous to mechanical and corrosion behaviors.[30,31] Nevertheless, the transformation of appropriate quantity of austenite and exclusion of intermetallic compounds is essential to conserve the quality. In general, DSS alloys with more than around 75% ferrite content is not suitable in maximum applications. DSS has the affinity to develop intermetallic compounds of chromium, molybdenum and iron if heated to 700–955°C temperature for an extended amount of time. The intermetallic compounds reduce the toughness and corrosion resistance. These compounds are formed at a very high rate in 815–870°C in DSS.[32,33]