Journal articles: 'Transition Metal Based Intermetallic Alloys'

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Hou, Xiao Jiang, Hong Chao Kou, Tie Bang Zhang, Rui Hu, Jin Shan Li, and Xiang Yi Xue. "First-Principles Studies on the Structures and Properties of Ti- and Zn-Substituted Mg₂Ni Hydrogen Storage Alloys and their Hydrides." Materials Science Forum 743-744 (January 2013): 44–52. http://dx.doi.org/10.4028/www.scientific.net/msf.743-744.44.

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In order to study the improvement mechanism of transition metal elements on Mg-based hydrogen storage alloys, especially for the structures and properties of hydrogen storage alloy Mg2Ni, Ti and Zn substituted alloys Mg2-mMmNi,Mg2Ni1-nMn (M=Ti and Zn, m, n=0.1667), and their hydrides Mg2NiH4,Mg2-mMmNiH4,Mg2Ni1-nMnH4(M=Ti and Zn, m , n=0.125) have been investigated by first-principles. Through analyzing the results of the crystal structure, electron density distribution and density of states, the changes of structures and properties resulting from the adding of transition metal elements Ti and V of intermetallic Mg2Ni and its hydride Mg2NiH4 were investigated. The results showed that the addition of transition metal elements can reduce the stability of the Mg2Ni system to varying degrees and improve the dehydrogenation dynamics performance. Therefore, it may be considered that the substitution by transition metal elements in Mg-based hydrogen storage alloys is an effective technique to improve the thermodynamic behavior of hydrogenation/dehydrogenation in Mg-based hydrogen storage alloys (HSAs).

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Amigó, Vicente, J. J. Candel, and P. Franconetti. "Titanium Metal Matrix Composite Laser Coatings Based on Carbides." Materials Science Forum 727-728 (August 2012): 299–304. http://dx.doi.org/10.4028/www.scientific.net/msf.727-728.299.

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Laser cladding is an adequate technique to fabricate Metal Matrix Composite (MMC) layers because of its focused high energy which allows the partial melting of hard ceramic reinforces particles like carbides. Thus, the wettability and gradual transition between metal and particle can be improved. However, metastable or new intermetallic phases can be formed during laser processing due to severe thermal cycle imposed to the clad with unknown properties in some cases. In this work our experience on microstructural analysis of Ti-MMC coatings acquired during the last five years is summarized. Special attention is paid on carbide dilution and secondary carbides formation mechanisms when TiC, SiC, Cr3C2, WC and B4C are mixed with titanium alloys.

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Micha, G. M., and L. Zhang. "Microstructural characterization of a cast RENi5-based alloy." Proceedings, annual meeting, Electron Microscopy Society of America 51 (August 1, 1993): 1176–77. http://dx.doi.org/10.1017/s0424820100151714.

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RENi5 (RE: rare earth) based alloys have been extensively evaluated for use as an electrode material for nickel-metal hydride batteries. A variety of alloys have been developed from the prototype intermetallic compound LaNi5. The use of mischmetal as a source of rare earth combined with transition metal and Al substitutions for Ni has caused the evolution of the alloy from a binary compound to one containing eight or more elements. This study evaluated the microstructural features of a complex commercial RENi5 based alloy using scanning and transmission electron microscopy.The alloy was evaluated in the as-cast condition. Its chemistry in at. pct. determined by bulk techniques was 12.1 La, 3.2 Ce, 1.5 Pr, 4.9 Nd, 50.2 Ni, 10.4 Co, 5.3 Mn and 2.0 Al. The as-cast material was of low strength, very brittle and contained a multitude of internal cracks. TEM foils could only be prepared by first embedding pieces of the alloy in epoxy.

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Gong, Qing, Qi Zhang, Hong Zhang, David A. Cullen, Sungho Jeon, Haoran Yu, Yang Ren, et al. "Amino Functionalization Approach to Synthesis of Carbon Supported Intermetallic Platinum-Based Alloy Catalysts for Fuel Cell Application." ECS Meeting Abstracts MA2022-02, no. 42 (October 9, 2022): 1548. http://dx.doi.org/10.1149/ma2022-02421548mtgabs.

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Platinum (Pt) is a critical element in making electrocatalysts for oxygen reduction reaction (ORR) occurring at the cathode of polymer electrolyte membrane fuel cells (PEMFCs). To address the Pt abundance issue and to enhance Pt catalysis, Pt is often alloyed with another transition metal M (i.e. M = Fe, Co, and Ni). Ordered intermetallic PtM alloys are considered as one of the most promising candidates to achieve both high activity and stability in practical fuel cell applications. The transition metals in ordered intermetallic PtM alloys occupy specific sites, and are stabilized by both metallic and ionic bonding. Ordered intermetallic structures are formed via high temperature (>600 °C) annealing of disordered PtM alloys, as the atomic ordering is a thermodynamically driven process. However, the high temperature annealing inevitably leads to the migration and agglomeration of the nanoparticles forming randomly alloyed particles with poor dispersion and broad size distributions, due to weak adhesions to the carbon support under typical processing conditions. To prevent this coalescence during annealing, protective coating of the nanoparticles with inorganic shells or physical barriers has been suggested. However, these studies were limited to the synthesis of intermetallic nanoparticles on carbon supports at low metal loadings, or require an additional step of removing the coating layer from the surface of the nanoparticles to expose the active sites. Thus, it is essential to develop a general approach that can produce highly dispersed, structurally ordered nanoparticles while achieving controls over the size and size distribution. We propose to use the functionalized carbon supports to control PtM alloy nanoparticle size and prevent nanoparticles from aggregating during the high temperature annealing through improving the metal-support interactions. A strong electrostatic attraction between the negative charge from Pt precursor (PtCl6 2 -) and positive charge from the amino groups (C-NH2+) on the surface of the functionalized carbon will be established during the wet impregnation synthesis. Such bonds will help to make the PtM nanoparticle size smaller and more uniformly distributed over the surface of support. The ordered intermetallic 30 wt.% PtCo/KB-NH2 catalyst demonstrated an average size of 2.7 nm and uniform size distribution. In addition, 30 wt.% PtCo/KB-NH2 catalyst exhibited a mass activity of 535 A/gPt (H2/O2) and a rated power density of 1.05 W/cm2 at 0.67 V (H2/air), meeting the DOE targets.

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Bocarsly, Andrew B., Aubrey R. Paris, Brian M. Foster, and Kai Alexander Filsinger. "(Keynote) New Classes of Copper-Free Electrocatalysts for CO2 Reduction Based on Transition Metal/Post Transition Metal Alloys and Intermetallic Compounds." ECS Meeting Abstracts MA2020-01, no. 51 (May 1, 2020): 2794. http://dx.doi.org/10.1149/ma2020-01512794mtgabs.

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Hernández-Negrete, Ofelia, and Panos Tsakiropoulos. "On the Microstructure and Isothermal Oxidation of the Si-22Fe-12Cr-12Al-10Ti-5Nb (at.%) Alloy." Materials 12, no. 11 (June 3, 2019): 1806. http://dx.doi.org/10.3390/ma12111806.

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Nb-silicide based alloys are new ultra-high temperature materials that could replace Ni-based superalloys. Environmentally resistant coating system (s) with αAl2O3 or SiO2 forming bond coat alloys that are chemically compatible with the Nb-silicide based alloy substrates are needed. This paper makes a contribution to the search for non-pesting bond coat alloys. The microstructure and isothermal oxidation at 800 °C of the silicide-based alloy Si-22Fe-12Cr-12Al-10Ti-5Nb (OHC2) were studied. The cast alloy exhibited macrosegregation of all elements. The microstructures in the cast alloy and after the heat treatment at 800 °C consisted of the same phases, namely TM6Si5, TM5Si3 (TM = transition metal), FeSi2Ti, Fe3Al2Si3, (Fe,Cr)(Si,Al), and an unknown phase of dark contrast. The latter two phases were not stable at 950 °C, where the TMSi2 was formed. There was evidence of endothermic reaction(s) below 1200 °C and liquation at 1200 °C. The alloy followed parabolic oxidation kinetics after the first hour of isothermal oxidation at 800 °C, did not pest, and formed a self-healing scale, in which the dominant oxide was Al2O3. The alloy was compared with other alumina or silica scale-forming intermetallic alloys and approaches to the design of bond coat alloys were suggested.

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Mukhachev, Roman D., and Alexey V. Lukoyanov. "Composition-Induced Magnetic Transition in GdMn1-xTixSi Intermetallic Compounds for x = 0–1." Metals 11, no. 8 (August 17, 2021): 1296. http://dx.doi.org/10.3390/met11081296.

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Magnetic intermetallic compounds based on rare earth elements and 3d transition metals are widely investigated due to the functionality of their physical properties and their variety of possible applications. In this work, we investigated the features of the electronic structure and magnetic properties of ternary intermetallic compounds based on gadolinium GdMn1-xTixSi, in the framework of the DFT + U method. Analysis of the densities of electronic states and magnetic moments of ions in Ti-doped GdMnSi showed a significant change in the magnetic properties depending on the contents of Mn and Ti. Together with the magnetic moment, an increase in the density of electronic states at the Fermi energy was found in almost all GdMn1-xTixSi compositions, which may indicate a significant change in the transport properties of intermetallic compounds. Together with the expected Curie temperatures above 300 K, the revealed changes in the magnetic characteristics and electronic structure make the GdMn1-xTixSi intermetallic system promising for use in microelectronic applications.

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Meng, Linggang, Bingwen Zhou, Bin Ya, Dong Jing, Yingxi Jiang, Danning Zhang, and Xingguo Zhang. "Microstructures and Properties of AlMgTi-Based Metal-Intermetallic Laminate Composites by Dual-Steps Vacuum Hot Pressing." Materials 13, no. 18 (September 5, 2020): 3932. http://dx.doi.org/10.3390/ma13183932.

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AlMgTi-based metal–intermetallic laminated composites were successfully fabricated through an innovative dual-step vacuum hot pressing. First, this study prepares the AlTi-based laminated composites by vacuum hot pressing at 650 °C. Then, the researchers place the Mg-Al-1Zn (AZ31) magnesium alloy between the prepared AlTi-based laminated composites at 430 °C for hot pressing. This study investigates the microstructure, phase composition, and microhardness distribution across interfaces of the intermetallics and metal. A multilayer phase (Mg17Al12, Al3Mg2, and transition layers) structure can be found from the diffusion layers between Al and AZ31. The microhardness of the material presents a wavy distribution in the direction perpendicular to the layers; the maximum can be up to 600.0 HV0.2 with a minimum of 28.7 HV0.2 The microhardness gradient of an AlMgTi-based composite is smoother due to the different microhardness of the layers, and reduces the interface stress concentration. The bending strength of AlMgTi-based composites can reach 265 MPa, and the specific strength is 105 × 103 Nm/kg, higher than AlTi-based composites.

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Ďuriška, Libor, Ivona Černičková, Pavol Priputen, and Marián Palcut. "Aqueous Corrosion of Aluminum-Transition Metal Alloys Composed of Structurally Complex Phases: A Review." Materials 14, no. 18 (September 19, 2021): 5418. http://dx.doi.org/10.3390/ma14185418.

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Complex metallic alloys (CMAs) are materials composed of structurally complex intermetallic phases (SCIPs). The SCIPs consist of large unit cells containing hundreds or even thousands of atoms. Well-defined atomic clusters are found in their structure, typically of icosahedral point group symmetry. In SCIPs, a long-range order is observed. Aluminum-based CMAs contain approximately 70 at.% Al. In this paper, the corrosion behavior of bulk Al-based CMAs is reviewed. The Al–TM alloys (TM = transition metal) have been sorted according to their chemical composition. The alloys tend to passivate because of high Al concentration. The Al–Cr alloys, for example, can form protective passive layers of considerable thickness in different electrolytes. In halide-containing solutions, however, the alloys are prone to pitting corrosion. The electrochemical activity of aluminum-transition metal SCIPs is primarily determined by electrode potential of the alloying element(s). Galvanic microcells form between different SCIPs which may further accelerate the localized corrosion attack. The electrochemical nobility of individual SCIPs increases with increasing concentration of noble elements. The SCIPs with electrochemically active elements tend to dissolve in contact with nobler particles. The SCIPs with noble metals are prone to selective de-alloying (de–aluminification) and their electrochemical activity may change over time as a result of de-alloying. The metal composition of the SCIPs has a primary influence on their corrosion properties. The structural complexity is secondary and becomes important when phases with similar chemical composition, but different crystal structure, come into close physical contact.

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Feng, Shikang, Enzo Liotti, and Patrick S. Grant. "X-ray Imaging of Alloy Solidification: Crystal Formation, Growth, Instability and Defects." Materials 15, no. 4 (February 10, 2022): 1319. http://dx.doi.org/10.3390/ma15041319.

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Synchrotron and laboratory-based X-ray imaging techniques have been increasingly used for in situ investigations of alloy solidification and other metal processes. Several reviews have been published in recent years that have focused on the development of in situ X-ray imaging techniques for metal solidification studies. Instead, this work provides a comprehensive review of knowledge provided by in situ X-ray imaging for improved understanding of solidification theories and emerging metal processing technologies. We first review insights related to crystal nucleation and growth mechanisms gained by in situ X-ray imaging, including solute suppressed nucleation theory of α-Al and intermetallic compound crystals, dendritic growth of α-Al and the twin plane re-entrant growth mechanism of faceted Fe-rich intermetallics. Second, we discuss the contribution of in situ X-ray studies in understanding microstructural instability, including dendrite fragmentation induced by solute-driven, dendrite root re-melting, instability of a planar solid/liquid interface, the cellular-to-dendritic transition and the columnar-to-equiaxed transition. Third, we review investigations of defect formation mechanisms during near-equilibrium solidification, including porosity and hot tear formation, and the associated liquid metal flow. Then, we discuss how X-ray imaging is being applied to the understanding and development of emerging metal processes that operate further from equilibrium, such as additive manufacturing. Finally, the outlook for future research opportunities and challenges is presented.

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Straumal, Boris, Kristina Tsoy, Aleksandr Druzhinin, Valery Orlov, Natalya Khrapova, Gregory Davdian, Gregory Gerstein, and Alexander Straumal. "Coexistence of Intermetallic Complexions and Bulk Particles in Grain Boundaries in the ZEK100 Alloy." Metals 13, no. 8 (August 6, 2023): 1407. http://dx.doi.org/10.3390/met13081407.

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Magnesium-based alloys are highly sought after in the industry due to their lightweight and reliable strength. However, the hexagonal crystal structure of magnesium results in the mechanical properties’ anisotropy. This anisotropy is effectively addressed by alloying magnesium with elements like zirconium, zinc, and rare earth metals (REM). The addition of these elements promotes rapid seed formation, yielding small grains with a uniform orientation distribution, thereby reducing anisotropy. Despite these benefits, the formation of intermetallic phases (IP) containing Zn, Zr, and REM within the microstructure can be a concern. Some of these IP phases can be exceedingly hard and brittle, thus weakening the material by providing easy pathways for crack propagation along grain boundaries (GBs). This issue becomes particularly significant if intermetallic phases form continuous layers along the entire GB between two neighboring GB triple junctions, a phenomenon known as complete GB wetting. To mitigate the risks associated with complete GB wetting and prevent the weakening of the alloy’s structure, understanding the potential occurrence of a GB wetting phase transition and how to control continuous GB layers of IP phases becomes crucial. In the investigation of a commercial magnesium alloy, ZEK100, the GB wetting phase transition (i.e., between complete and partial GB wetting) was successfully studied and confirmed. Notably, complete GB wetting was observed at temperatures near the liquidus point of the alloy. However, at lower temperatures, a coexistence of a nano-scaled precipitate film and bulk particles with nonzero contact angles within the same GB was observed. This insight into the wetting transition characteristics holds potential to expand the range of applications for the present alloy in the industry. By understanding and controlling GB wetting phenomena, the alloy’s mechanical properties and structural integrity can be enhanced, paving the way for its wider utilization in various industrial applications.

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Popova, Elvira, Pavel Kotenkov, Ivan Gilev, Stepan Pryanichnikov, and Alexey Shubin. "Effect of Copper on the Formation of L12 Intermetallic Phases in Al–Cu–X (X = Ti, Zr, Hf) Alloys." Metals 12, no. 12 (November 30, 2022): 2067. http://dx.doi.org/10.3390/met12122067.

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Transition metal trialuminides of the Al3X type of groups 4 and 5 of the periodic system have reduced density, high melting points, and corrosion resistance. Aluminides with a cubic lattice of the Al3Sc type can be used as a nucleating phase for aluminum alloys. However, low plasticity and a tetragonal lattice limit their application. In this work, we stabilized the metastable cubic lattice of Al3X-type aluminides by replacing aluminum with copper. The conditions for the formation of L12 metastable aluminides in the Al‒Cu‒TM (TM: Ti, Zr, Hf) alloys were studied using a wide range of copper concentrations. A high concentration of copper (hypereutectic alloys) is the one of the necessary conditions for the formation of (Al1−хCuх)3Ti, (Al1−хCuх)3Zr, (Al1−хCuх)3Hf aluminides. With an increase in the copper concentration, the number of metastable aluminides sharply increased. The process of their formation strongly depended on the sequence of dissolution of the corresponding components in the melts. The low volume fraction of precipitated titanium aluminides was the result of insufficient supersaturation of α-Al with titanium (at the peritectic temperature) compared to that for alloys with zirconium and hafnium. Under identical synthesis conditions in the crystal lattice of metastable aluminides formed in experimental Al–Cu–Ti, Al–Cu–Zr, Al–Cu–Hf alloys, copper was found to substitute up to 8, 10, and 13 at.% of aluminum, respectively. The crystallographic and dimensional similarities of the lattices in metastable transition metal aluminides and in α-Al suggest their usefulness as modifying additions in aluminum-based alloys.

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Chen, R. S., J. T. Guo, W. L. Zhou, and J. Y. Zhou. "Brittle-to-ductile transition of a multiphase intermetallic alloy based on NiAl." Intermetallics 8, no. 5-6 (May 2000): 663–67. http://dx.doi.org/10.1016/s0966-9795(99)00167-3.

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Lazarev, P. A., M. L. Busurina, A. N. Gryadunov, A. E. Sytschev, and A. F. Belikova. "Fabrication of (Ti-Al-Si)/(Ti-C)/Ti – layered alloy by SHS pressing." Powder Metallurgy аnd Functional Coatings, no. 1 (March 14, 2023): 21–27. http://dx.doi.org/10.17073/1997-308x-2023-1-21-27.

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A metal-carbide-intermetallic material based on combustion products of the layer system (Ti-Al-Si)/(Ti-C)/Ti was for the first time obtained with the help of self-propagating high-temperature synthesis (SHS) combined with pressing. Exothermic synthesis from elementary powders was carried out at a pressure of 10 MPa, and pressing of the hot synthesis product was carried out at a pressure of 100 MPa. It has been shown that SHS pressing contributes to the formation of permanent joints of «metal/carbide/intermetallic» layers. The main features of microstructure formation, phase composition, and strength properties of transition zones at the boundary between reacting SHS compositions, Ti-C and Ti-Al-Si and Ti-metal substrate are investigated. It is shown that during SHS reaction, a homogeneous microstructure of Ti-C and Ti-Al-Si layers with an insignificant content of cracks and pores is formed. The thickness of the transition zone between the layers was at least 15 µm. The main phase formed in the combustion product of Ti-Al-Si layer is, according to the results of X-ray phase analysis, triple phase Ti20Al3Si9, the content of which, calculated by the Rietveld method, was at least 87 wt. %. In addition, the combustion product contains a secondary phase of Ti3Al in the amount of 13 wt. %. The energy dispersion analysis revealed that diffusion of aluminium through the titanium carbide layer into the titanium substrate to a depth of approx. 30 µm is observed. Microhardness value of the combustion product of Ti-Al-Si layer was about 10 GPa. The rectilinear nature of crack propagation in the synthesized combustion product of Ti-Al-Si layer, as well as the Palmquist crack resistance coefficient varying within 5.1-5.7 MPa·m1/2, indicate the fragility of the material.

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Carbonari, Artur Wilson, José Mestnik-Filho, and Rajendra Narain Saxena. "Impurities in Magnetic Materials Studied by PAC Spectroscopy." Defect and Diffusion Forum 311 (March 2011): 39–61. http://dx.doi.org/10.4028/www.scientific.net/ddf.311.39.

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Perturbed gamma-gamma angular correlation (PAC) spectroscopy is a precise and highly efficient tool to follow the temperature dependence of local magnetic fields in any material. Its resolution and efficiency does not depend on temperature and therefore can measure local fields at low as well as high temperature with the same accuracy. Due its versatility in using different probe nuclei it can sense the local magnetic fields at different sites in the crystalline structure of materials. In this review, important results obtained with PAC spectroscopy are shown in two classes of materials: transition metal and transition-metal based compounds and rare earth elements and rare-earth-element based compounds using mainly three different probe nuclei:111Cd,181Ta and140Ce. PAC spectroscopy has contributed to the systematic study of the magnetic hyperfine field in impurities in matrices of Fe, Co and Ni as well as in transition-metal based Heusler alloys. It has also provided important contribution to the investigation of magnetism in rare-earth elements and intermetallic compounds. An still open issue concerning the local fields in metallic magnetic compounds and elements is the exchange interaction between the magnetic ions of the host and a dilute magnetic impurity, which acts as a defect in the magnetic lattice. PAC spectroscopy has been contributing to study this problem with success. Also shown in this review is the crucial role of ab-initio first principle calculations in the interpretation of PAC results.

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Pan, Hao, Yue Wang, Shaoning Geng, Annan Yin, Chu Han, and Jintian Zhao. "Study on Laser Overlap Welding of Titanium/Aluminum Dissimilar Metals Based on Niobium Microalloying." Metals 13, no. 7 (July 11, 2023): 1257. http://dx.doi.org/10.3390/met13071257.

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Brittle intermetallic compounds, formed during the welding process of titanium/aluminum (Ti/Al), lead to a significant reduction in joint mechanical properties. The purpose of this study is to mitigate the formation of brittle phases during the laser welding of dissimilar Ti/Al metals, thereby enhancing the mechanical properties of the joints. In this investigation, an innovative approach is adopted, utilizing Nb foil as an interlayer to effectively minimize the formation of brittle intermetallic phases during dissimilar welding. A comprehensive analysis of the microstructure of the transition layer was conducted using material characterization methods, including scanning electron microscope equipped with an energy dispersive X-ray spectrometer. The mechanical performance of the welded joints was assessed using tensile testing. The results indicate that the effective welding width and joint penetration depth at the joint interface were reduced in Ti/Al dissimilar metals when Nb was added as an intermediate layer, under the same welding process parameters, when compared to unalloyed weld seams. Furthermore, the utilization of a 0.05 mm Nb foil as the intermediate layer results in a significant 25% increase in the average shear strength compared to the other condition, with the average shear strength of the joint reaching its peak value at 192 N/mm. The unalloyed Ti/Al weld joint usually fractured along the melting zone, displaying complete brittle fracture characteristics. After Nb microalloying, the joint typically fractures along the transition zone and interface, exhibiting both cleavage and ductile fracture characteristics, indicating the combination of a brittle and toughness fracture. This study provides experimental evidence and new insights for welding Ti/Al composite structures, with significant theoretical and practical applications.

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Pawłowski, A., C. Senderowski, W. Wołczyński, J. Morgiel, and Ł. Major. "Detonation Deposited Fe-Al Coatings Part II: Transmission Electron Microscopy of Interlayers and Fe-Al Intermetallic Coating Detonation Sprayed onto the 045 Steel Substrate." Archives of Metallurgy and Materials 56, no. 1 (March 1, 2011): 71–79. http://dx.doi.org/10.2478/v10172-011-0008-x.

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Detonation Deposited Fe-Al Coatings Part II: Transmission Electron Microscopy of Interlayers and Fe-Al Intermetallic Coating Detonation Sprayed onto the 045 Steel Substrate The microstructure of detonation gaseous sprayed (DGS) transition layers of Ni(Al), Ni(Cr) and subsequent coating of Fe-Al intermetallic phases deposited on the 045 steel were studied in the paper using transmission electron microscopy. In order to identify phases in the particular interlayers the selected area electron diffraction (SAED) and an energy dispersive X-ray microanalysis (EDX) were applied. It was found that the Ni(Al) interlayer contained basically pure nickel with a small fraction of NiAl phase. The Al based amorphous phase was also observed its area in the form of bands. The Ni(Cr) interlayer basically contained Ni-rich small grains. Pure chromium in the Ni matrix appeared in the vicinity of Fe-Al coating in the shape of bow-like bands, parallel to the coating. The boundary between the Ni(Cr) layer and the Fe-Al coating revealed abrupt decrease of the Ni content in the coating at simultaneous rapid increase of the Fe amount. Improper Al/Cr ratio within the Ni matrix seems to be responsible for the formation of Al-oxides and the bands of almost pure Cr and Ni(Cr) layers and resulting decrease of interlayer adherence.

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Sanin, Vitalii V., Maksym I. Aheiev, Yury Yu Kaplanskii, Pavel A. Loginov, Marina Ya Bychkova, and Evgeny A. Levashov. "The Effect of Dopants on Structure Formation and Properties of Cast SHS Alloys Based on Nickel Monoaluminide." Materials 16, no. 9 (April 22, 2023): 3299. http://dx.doi.org/10.3390/ma16093299.

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Alloys based on NiAl-Cr-Co (base) with complex dopants (base+2.5Mo-0.5Re-0.5Ta, base+2.5Mo-1.5Re-1.5Ta, base+2.5Mo-1.5Ta-1.5La-0.5Ru, base+2.5Mo-1.5Re-1.5Ta-0.2Ti, base+2.5Mo-1.5Re-1.5Ta-0.2Zr) were fabricated by centrifugal SHS metallurgy. The phase and impurity compositions, structure, mechanical properties, and the mechanism of high-temperature oxidation at T = 1150 °C were studied; the kinetic oxidation curves, fitting equations and parabolic rate constant were plotted. Al2O3 and Co2CrO4 were the major phases of the oxidized layer. Three layers were formed: I—the continuous Al2O3 layer with Co2CrO4 inclusions; II—the transitional MeN-Me layer with AlN inclusions; and III—the metal layer with AlN inclusions. The positive effect of thermo-vacuum treatment (TVT) on high-temperature oxidation resistance of the alloy was observed. The total weight gain by the samples after oxidative annealing decreased threefold (from 120 ± 5 g/m2 to 40 ± 5 g/m2). The phases containing Ru and Ti microdopants, which reduced the content of dissolved nitrogen and oxygen in the intermetallic phase to the values ∑O, N = 0.0145 wt.% for the base+2.5Mo-1.5Ta-1.5La-0.5Ru alloy and ∑O,N = 0.0223 wt.% for the base+2.5Mo-1.5Re-1.5Ta-0.2Ti alloy, were identified by transmission electron microscopy (TEM). In addition, with the significant high-temperature oxidation resistance, the latter alloy with Ti had the optimal combination of mechanical properties (σucs = 1644 ± 30 MPa; σys = 1518 ± 25 MPa).

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Скачков, Владимир Михайлович. "CHANGE IN PROPERTIES OF DIFFUSION-HARDENING SOLDER IN DEPENDENCE ON THE COMPOSITION OF THE LIQUID METAL COMPONENT." Physical and Chemical Aspects of the Study of Clusters, Nanostructures and Nanomaterials, no. 13 (December 23, 2021): 788–95. http://dx.doi.org/10.26456/pcascnn/2021.13.788.

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В статье обсуждается изменение свойств диффузионно-твердеющего припоя в зависимости от состава жидкометаллической компоненты на основе легкоплавких сплавов галлия: галлий-олово, галлий-индий-олово и галлий-олово-цинк при взаимодействии с порошком сплава медь-олово (ПМОСФ5) подвергнутых низкотемпературной (125 °С) и высокотемпературной (500 °С) термической обработке. Механические свойства оценены измерением микротвердости, а термические исследованы методом дифференциально-термического анализа. Термическая обработка при высоких температурах способствует переходу припоя в равновесное состояние, при этом происходит значительное увеличение твердости. По графикам дифференциальнотермического анализа рассчитаны экзотермические эффекты. Методом рентгенофазового анализа определены образующиеся в результате диффузионного твердения фазы. Показано, что при различных температурах обработки образуются разные фазы - наноразмерные интерметаллические соединения. Экспериментально доказано улучшение механических свойств диффузионно-твердеющего припоя при наличии цинка растворенного в галлиевом жидком сплаве. The article discusses the change in the properties of diffusion-hardening solder in dependence on the composition of the liquid metal component based on low-melting gallium alloys: gallium-tin, gallium-indium-tin and gallium-tin-zinc when interacting with the Spherical copper-tin alloy powder (SCTAP5) subjected to low-temperature (125 °С) and high-temperature (500 °С) heat treatment. The mechanical properties were evaluated by measuring the microhardness, and the thermal properties were studied by differential thermal analysis. Heat treatment at high temperatures promotes the transition of the solder to an equilibrium state, with a significant increase in hardness. The thermal effects of heat treatment of diffusion-hardening solders are calculated and compared. The phases formed as a result of hardening are determined by X-ray phase analysis. It is shown that different phases and nanoscale intermetallic compounds are formed at different processing temperatures. The improvement of the mechanical properties of diffusion-hardening solder in the presence of zinc dissolved in a gallium liquid alloy has been experimentally proved.

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Wang, Tianhao, Bharat Gwalani, Joshua Silverstein, Jens Darsell, Saumyadeep Jana, Timothy Roosendaal, Angel Ortiz, Wayne Daye, Tom Pelletiers, and Scott Whalen. "Microstructural Assessment of a Multiple-Intermetallic-Strengthened Aluminum Alloy Produced from Gas-Atomized Powder by Hot Extrusion and Friction Extrusion." Materials 13, no. 23 (November 25, 2020): 5333. http://dx.doi.org/10.3390/ma13235333.

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An aluminum (Al) matrix with various transition metal (TM) additions is an effective alloying approach for developing high-specific-strength materials for use at elevated temperatures. Conventional fabrication processes such as casting or fusion-related methods are not capable of producing Al–TM alloys in bulk form. Solid phase processing techniques, such as extrusion, have been shown to maintain the microstructure of Al–TM alloys. In this study, extrusions are fabricated from gas-atomized aluminum powders (≈100–400 µm) that contain 12.4 wt % TM additives and an Al-based matrix reinforced by various Al–Fe–Cr–Ti intermetallic compounds (IMCs). Two different extrusion techniques, conventional hot extrusion and friction extrusion, are compared using fabricating rods. During extrusion, the strengthening IMC phases were extensively refined as a result of severe plastic deformation. Furthermore, the quasicrystal approximant IMC phase (70.4 wt % Al, 20.4 wt % Fe, 8.7 wt % Cr, 0.6 wt % Ti) observed in the powder precursor is replaced by new IMC phases such as Al3.2Fe and Al45Cr7-type IMCs. The Al3Ti-type IMC phase is partially dissolved into the Al matrix during extrusion. The combination of linear and rotational shear in the friction extrusion process caused severe deformation in the powders, which allowed for a higher extrusion ratio, eliminated linear voids, and resulted in higher ductility while maintaining strength comparable to that resulting from hot extrusion. Results from equilibrium thermodynamic calculations show that the strengthening IMC phases are stable at elevated temperatures (up to ≈ 600 °C), thus enhancing the high-temperature strength of the extrudates.

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Tsakiropoulos, Panos. "On the Nb5Si3 Silicide in Metallic Ultra-High Temperature Materials." Metals 13, no. 6 (May 26, 2023): 1023. http://dx.doi.org/10.3390/met13061023.

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Refractory metal (RM) M5Si3 silicides are desirable intermetallics in metallic ultra-high temperature materials (UHTMs), owing to their creep properties and high Si content that benefits oxidation resistance. Of particular interest is the alloyed Nb5Si3 that forms in metallic UHTMs with Nb and Si addition. The choice of alloying elements and type of Nb5Si3 that is critical for achieving a balance of properties or meeting a property goal in a metallic UHTM is considered in this paper. Specifically, the different types of alloyed “normal” Nb5Si3 and Ti-rich Nb5Si3, namely “conventional”, “complex concentrated” (CC) or “high entropy” (HE) silicide, in metallic UHTMs with Nb and Si addition were studied. Advanced metallic UHTMs with additions of RMs, transition metals (TMs), Ge, Sn or Ge + Sn and with/without Al and with different Ti, Al, Cr, Si or Sn concentrations were investigated, considering that the motivation of this work was to support the design and development of metallic-UHTMs. The study of the alloyed silicides was based on the Nb/(Ti + Hf) ratio, which is key regarding creep, the parameters VEC and Δχ and relationships between them. The effect of alloying additions on the stability of “conventional”, CC or HE silicide was discussed. The creep and hardness of alloyed Nb5Si3 was considered. Relationships that link “conventional”, CC or HE bcc solid solution and Nb5Si3 in the alloy design methodology NICE (Niobium Intermetallic Composite Elaboration) were presented. For a given temperature and stress, the steady state creep rate of the alloyed silicide, in which TMs substituted Nb, and Al and B substituted Si, depended on its parameters VEC and Δχ and its Nb/(Ti + Hf) ratio, and increased with decreasing parameter and ratio value, compared with the unalloyed Nb5Si3. Types of alloyed Nb5Si3 with VEC and Δχ values closest to those of the unalloyed Nb5Si3 were identified in maps of alloyed Nb5Si3. Good agreement was shown between the calculated hardness and chemical composition of Nb5Si3 and experimental results.

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Li, Yi Shan, Bin Han, and Cai Gao. "Microstructure Characteristic of Laser Cladding Ceramic Layer on High Cr Cast Steel Surface." Advanced Materials Research 652-654 (January 2013): 1866–70. http://dx.doi.org/10.4028/www.scientific.net/amr.652-654.1866.

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The Al2O3 gradient ceramics coating was cladded on the high Cr cast steel by 5KW crosscurrent CO2 laser with Ni-based alloy which was used as transition metal in this experiment. The microstructure is analyzed with optics microstructure analyzer and the crystal grain characteristic is studied. The results show that the microstructure of laser cladding layer contains the plane crystal zone which grows along the substrate, the cellular crystal zone, the dendritic crystal zone and the surface equiaxed cryatal zone. The microstructure of the coating compared with the substrate is extremely fine, and the microstructure of multi-layer cladding presents stratification. The phase composition of the cladding layer is composed primarily of NiAl intermetallic compound, also includes γ-FeNi and a little Ni3Al compound. The Al2O3 particles that some present the single crystal form and some accumulate in together, play the dispersion strengthening role in the coating material. The massive twin crystals and the dislocation pile-ups are found to exist in the cladding layer.

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23

Liu, Jiankun, Guanpeng Liu, Hua Ouyang, Yulong Li, Ming Yan, and Michael Pecht. "Wetting Kinetics and Microstructure Analysis of BNi2 Filler Metal over Selective Laser Melted Ti-6Al-4V Substrate." Materials 13, no. 20 (October 20, 2020): 4666. http://dx.doi.org/10.3390/ma13204666.

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The wetting kinetics of nickel-based filler metal (BNi2) over selective laser-melted Ti-6Al-4V (SLMed TC4) titanium alloy in a protective argon atmosphere is experimentally investigated using a real-time in situ hot stage equipped with an optical microscope. The spreading processes at different temperatures are similar, and the overall wetting/spreading process can be roughly divided into three stages: (i) an initial stage, (ii) a rapid spreading stage, and (iii) an asymptotic stage. Moreover, the wetting kinetics of the BNi2/SLMed TC4 system can be expressed by empirical power exponential function Rn~t with n = ~1. In the process of spreading, Ti-based solid solution (Ti(ss)) and intermetallic compound (Ti2Ni and TiB2) were formed at the interface within the reaction domain, and the phase transition of α’ martensitic to α-Ti and β-Ti also took place. The influence of elevated temperature on the spreading and wetting kinetics of the BNi2/SLMed TC4 system was studied, and the results show that the increase of temperature has a slightly promoting effect on the spreading, but a limited impact on the value of n. In addition, the spreading and wetting kinetics of BNi2/SLMed TC4 system are similar to those of BNi2 on conventional forged TC4 substrate.

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Li, Junzhao, Yibo Liu, Zuyang Zhen, Peng Jin, Qingjie Sun, and Jicai Feng. "Weld Formation Mechanism and Microstructural Evolution of TC4/304 Stainless Steel Joint with Cu-Based Filler Wire and Preheating." Materials 12, no. 19 (September 20, 2019): 3071. http://dx.doi.org/10.3390/ma12193071.

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Ti-Fe intermetallic compounds were effectively suppressed with Cu-based filler wire and weld formation was greatly improved with the preheating of substrates when joining TC4 titanium alloy and 304 stainless steel. A Ti/Cu transition zone consisting of complex TiCu, Ti2Cu3, TiFe, and TiFe2 phases was formed between Cu-weld/TC4 interface, while Cu-weld/304ss interface was mainly composed of α-Fe and ε-Cu solid solution. At lower heat input, the undercut defect in back surface had potential to cause crack initiation and joint fracture. Though increasing heat input would improve weld morphology, the formation of thick interfacial reaction layer and weld cracking led to low weld quality and joint strength. The preheating of substrates had an obvious effect on wetting ability of liquid filler metal and could achieve a better weld quality at lower heat input. The back formation of weld was improved to decrease the occurrence of weld defects. The highest tensile strength of 365 MPa occurred at welding heat input of 0.483 kJ/cm, increasing by 47% compared to the joint without preheating. The interfacial reaction mechanism was discussed to reveal the relationship between microstructural characteristics and fracture behavior of Ti/steel welded joints with Cu-based filler wire.

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Yang, Liuqing, Zhiyong Li, Boqiong Li, Yingqiao Zhang, Shouzheng Wei, and Yanlong Jia. "Simulations and Experiments on the Microstructure and Property Evolution of In Situ TiC+Al3Ti-Reinforced Aluminum Coatings on AZ91D Magnesium Alloy." Crystals 13, no. 7 (July 24, 2023): 1151. http://dx.doi.org/10.3390/cryst13071151.

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With the development of computational thermodynamics, it is possible to design a material based on its simulated microstructure and properties before practical operations. In order to improve the surface properties of AZ91D magnesium alloy, Jmatpro was used in this study to design an alloy system with in situ TiC+AlTi3-reinforced aluminum coatings. The Gibbs free energy, hardness, and phase diagrams of aluminum coatings with different ratios of Ti to B4C were simulated. According to the simulation results, TiB2, TiC, Al3Ti_DO22, and Al4C3 were formed in the coating while TiB2, TiC, Al3Ti_DO22, Al4C3, and Al3Mg2 were formed in the transition zone between the base metal and the coating. Based on the simulation results, different amounts of Ti were used with B4C (the ratios were 3:1, 4:1, 5:1, and 6:1) to fabricate TiC+Al3Ti reinforced aluminum coatings on AZ91D magnesium alloy via laser cladding. The microstructure and phase composition of the coating were studied using scanning electron microscopy (SEM) incorporated with energy- dispersive spectrometry (EDS) and X-ray diffraction (XRD). The results indicated that intermetallic phases, such as AlTi3(C, N)0.6, AlMg, Al3Mg2, Al3Ti, and TiC were formed in the coatings. As the Ti content increased, the content of Al3Ti increased and the content of TiC decreased in the coatings, which is consistent with the simulation results. The average hardness of the coatings was approximately four to five times that of the magnesium alloy substrate, and the corrosion current density of the coatings was around 2.5 × 10−6, which is two orders of magnitude lower than that of AZ91D magnesium alloy.

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Belin-Ferré, Esther, and Jean Marie Dubois. "Wetting of aluminium-based complex metallic alloys." International Journal of Materials Research 97, no. 7 (July 1, 2006): 985–95. http://dx.doi.org/10.1515/ijmr-2006-0156.

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Abstract Many complex metallic alloys are known to form in aluminium-based systems containing transition metals like Cu, Pd, Fe or Cr, the most famous one being the stable icosahedral quasicrystal discovered in the Al –Cu –Fe system. Although covered by a thin native oxide layer, adhesion of water onto the complex compounds is very different from that onto the oxide or onto oxidised aluminium. We show here how this atypical behaviour is related to the structural complexity of the compound. We then produce data that allows us to estimate the actual surface energy of the same compounds, a property that is also a fingerprint of structural complexity in Al-based intermetallics.

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Busurina, M. L., A. E. Sytschev, A. V. Karpov, N. V. Sachkova, and I. D. Kovalev. "Synthesis of Cu–Ti–Al-based intermetallic alloy. Structural phase analysis and electrophysical properties." Izvestiya Vuzov. Tsvetnaya Metallurgiya (Universities' Proceedings Non-Ferrous Metallurgy), no. 6 (December 16, 2020): 87–94. http://dx.doi.org/10.17073/0021-3438-2020-6-87-94.

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For the first time, an intermetallic alloy based on the Heusler phase – Cu2TiAl – was obtained by self-propagating high-temperature synthesis (SHS) in the Cu–Ti–Al reaction mixture. The frontal combustion modes of green mixture compositions and phase formation processes during synthesis were studied. The products obtained were studied by X-ray diffraction analysis including high-temperature diffractometry with stage heating up to 900 K, scanning electron microscopy, differential thermal analysis (DTA), and some physical properties were studied. Also, electrophysical and magnetic measurements were carried out for the obtained alloy. The results of X-ray analysis and SEM using energy-dispersive analysis (EDA) showed that the Heusler phase content in the synthesized product is at least 82 %. The product also contains copper (Cu9Al4) and titanium (Ti3Al2) aluminides. The temperature dependence of the synthesized product electrical resistivity was measured for a wide temperature range of 90–1000 K, which was 0.3 μmm at T = 300 K. The metallic type of the conductivity for the samples obtained and the abnormal behavior of the electrical resistance temperature curve in the region of Т = 770÷790 K were revealed. Thermal analysis was used to measure the melting point of the synthesized product and to reveal additional heat effects at Т = 788, 848 and 1248 К associated with possible phase transitions in the Cu2TiAl intermetallic compound. A possible mechanism of phase transitions is considered in accordance with the Cu–Ti–Al system phase diagram. Magnetic measurements results showed that intermetallic samples obtained by the SHS method feature by weak ferromagnetic properties with residual magnetization of 0.069 A·m2/kg.

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Gao, Chao, Lingkun Zhang, and Bingrong Zhang. "Effect of Transition Metal Elements on High-Temperature Properties of Al–Si–Cu–Mg Alloys." Metals 11, no. 2 (February 20, 2021): 357. http://dx.doi.org/10.3390/met11020357.

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In the present work, we studied the effects of transition metal elements on microstructure evolution and high-temperature mechanical properties via the preparation of new modified alloys with micro-additions of Cr, Ti, V, Zr, Mo, and Mn to address the poor high-temperature performance of Al–Si–Cu–Mg alloys for automotive engines. The results show that the addition of transition metal elements formed a variety of new intermetallic phases that were stable at high temperatures, such as (AlSi)3(TiVZr), (AlSi)3Ti, (AlSi)3(CrVTi), Al74Si6Mn4Cr2Fe, Al85Si5Mn2Mo2CrFe, Al0.78Fe4.8Mn0.27Mo4.15Si2, (AlSi)2(CrVTi)Mo, and Al13(MoCrVTi)4Si4, and these phases evidently improved the ultimate high-temperature tensile strength and yield strength. The ultimate tensile strength and yield strength of the modified alloy increased by 17.49% and 31.65% when the test temperature increased to 240 °C, respectively, and by 71.28% and 74.73% when the test temperature increased to 300 °C, respectively. The fundamental reason for this change is that the intermetallic phase hinders the expansion of cracks, which can exist stably at high temperatures. When a crack extends to the intermetallic phases, it will break along with the intermetallic phases or propagate along the morphological edge of the intermetallic phases.

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Chu, F., T. E. Mitchell, S. P. Chen, M. Sob, R. Siegl, and D. P. Pope. "Phase stability and elasticity of C15 transition-metal intermetallic compounds." Journal of Phase Equilibria 18, no. 6 (December 1997): 536–43. http://dx.doi.org/10.1007/bf02665807.

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30

Zhang, Heng, E. Wu, S. J. Campbell, S. J. Kennedy, H. S. Li, A. J. Studer, S. R. Bulcock, and A. D. Rae. "Structural study of the rare-earth transition-metal intermetallic compound Nd3Ni29Si4B10." Journal of Alloys and Compounds 278, no. 1-2 (August 1998): 239–45. http://dx.doi.org/10.1016/s0925-8388(98)00596-9.

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31

Morinaga, M., N. Yukawa, H. Ezaki, and H. Adachi. "Solid solubilities in transition-metal-based f.c.c. alloys." Philosophical Magazine A 51, no. 2 (February 1, 1985): 223–46. http://dx.doi.org/10.1080/01418610.1985.12069159.

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32

Shimojima, Koji, Hiroyuki Hosokawa, Ryoichi Furushima, Kiyotaka Katou, and Akihiro Matsumoto. "Improvement of Wet Milled TiC-Feal Alloys." Advanced Materials Research 1088 (February 2015): 135–39. http://dx.doi.org/10.4028/www.scientific.net/amr.1088.135.

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TiC based cermet is a candidate material for alternatives of WC-Co used in tools/dies. Ordinary, Ni and Co, etc. are used as a metal binder of TiC based cermet. They are kinds of rare metals, therefore it is desired that metal binders are also replaced with the ubiquitous materials. FeAl intermetallic alloys are one of candidate materials of alternative rare metal binder made from ubiquitous materials. FeAl is well-known as an extremely resistance material to corrosion under oxidizing atmospheres, sulfidizing atmospheres, and in molten salts. Combination of intermetallic and carbide, the hardness is very high, but it would be brittle. In this work, TiC-FeAl alloys are made by wet milling and pulsed electric current sintering to improve transverse rupture strength while the hardness is kept. We achieved that TiC-40 vol. % (Fe-40 at. % Al) alloy with hardness of 17.7 GPa and T.R.S. of 1.9 GPa.

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Han, J. P., and Y. Q. Guo. "Structure stability and magnetic properties of RIn3−xTx (R = Gd, Pr,T = Co, Fe, Mn)." Powder Diffraction 32, no. 4 (December 2017): 249–54. http://dx.doi.org/10.1017/s0885715617001142.

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The syntheses and crystal structures and magnetic properties of novel RIn3−xTx (R = Gd，Pr；T = Fe，Co，Mn；x = 0–0.3) intermetallic compounds in rare earth-In-3d transition metal ternary system have been systematically investigated. It reveals that RIn3−xTx crystallizes in cubic AuCu3 type structure with a space group of Pm$\bar 3$m and Z = 1. The 1a and 3c crystal positions are occupied by R and In atoms, respectively. The 3d transition metals substitute partly for In and prefer to occupy the 3c site. The lattice parameters and unit cell volumes decrease with increasing the content of 3d transition metal in RIn3−xTx intermetallic compounds. The magnetic properties of RIn3−xTx are sensitive to T content. With increasing T content, GdIn3−xTx alloys show the paramagnetic, mixture of ferromagnetic and paramagnetic and ferromagnetic behavior. T doping into RIn3 induces the presence of ferromagnetic phase in GdIn3−xTx, which is totally different from those of the pure binary RIn3.

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34

Belomyttsev, M. Yu, M. S. Evseev, D. A. Kozlov, K. K. Kreitser, V. V. Safonov, L. G. Chernukha, and M. A. Shtremel’. "Heat resistance of metal-intermetallic compositions based on NiAl." Russian Journal of Non-Ferrous Metals 48, no. 6 (December 2007): 507–10. http://dx.doi.org/10.3103/s1067821207060235.

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Botton, G. A., and C. J. Humphreys. "Electron energy loss near edge structures of intermetallic alloys and grain boundaries in NiAl." Proceedings, annual meeting, Electron Microscopy Society of America 54 (August 11, 1996): 522–23. http://dx.doi.org/10.1017/s0424820100165070.

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Transition metal aluminides are of great potential interest for high temperature structural applications. Although these materials exhibit good mechanical properties at high temperature, their use in industrial applications is often limited by their intrinsic room temperature brittleness. Whilst this particular yield behaviour is directly related to the defect structure, the properties of the defects (in particular the mobility of dislocations and the slip system on which these dislocations move) are ultimately determined by the electronic structure and bonding in these materials. The lack of ductility has been attributed, at least in part, to the mixed bonding character (metallic and covalent) as inferred from ab-initio calculations. In this work, we analyse energy loss spectra and discuss the features of the near edge structure in terms of the relevant electronic states in order to compare the predictions on bonding directly with spectroscopic experiments. In this process, we compare spectra of late transition metal (TM) to early TM aluminides (FeAl and TiAl) to assess whether differences in bonding can also be detected. This information is then discussed in terms of bonding changes at grain boundaries in NiAl.

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Schroer, Carsten. "Dissimilar Metal Solution from Solid Alloys as Observed for Steels and Nickel‐Based Alloys in the Presence of Lead‐Based Liquid Alloys or Liquid Tin." JOM 73, no. 12 (November 2, 2021): 4000–4008. http://dx.doi.org/10.1007/s11837-021-04948-9.

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AbstractThe solution of elements from metallic alloys is analyzed, notably the initial stage characterized by solution in proportion to the alloy composition and subsequent selective leaching of alloying elements. For the latter stage of the process, characteristic features of the originating depletion zone are derived for different formation mechanisms. The results are compared with observations for steels and nickel-based alloys after exposure to lead-based liquid alloys or liquid tin, and, where possible, the prevailing mechanism is identified. Furthermore, the influence of dissolved oxygen and formation of intermetallic compounds are addressed.

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Reddy, P. Venugopal, and D. Akhtar. "Transport properties of some transition-metal-based amorphous alloys." Journal of the Less Common Metals 138, no. 1 (March 1988): L5—L10. http://dx.doi.org/10.1016/0022-5088(88)90249-4.

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Vas'kovskij, V. O., V. N. Lepalovskij, V. G. Muhchametov, and Ju M. Jarmoshenco. "Sandwich magnetoresistive films based on 3d-transition metal alloys." Journal of Magnetism and Magnetic Materials 148, no. 1-2 (July 1995): 325–26. http://dx.doi.org/10.1016/0304-8853(95)00256-1.

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Kudrnovský, Josef, and Václav Drchal. "Magnetic properties of fcc Ni-based transition metal alloys." International Journal of Materials Research 100, no. 9 (September 2009): 1193–96. http://dx.doi.org/10.3139/146.110170.

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Beranoagirre, Aitor, Gorka Urbikain, Amaia Calleja, and Luis López de Lacalle. "Drilling Process in γ-TiAl Intermetallic Alloys." Materials 11, no. 12 (November 26, 2018): 2379. http://dx.doi.org/10.3390/ma11122379.

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Gamma titanium aluminides (γ-TiAl) present an excellent behavior under high temperature conditions, being a feasible alternative to nickel-based superalloy components in the aeroengine sector. However, considered as a difficult to cut material, process cutting parameters require special study to guarantee component quality. In this work, a developed drilling mechanistic model is a useful tool in order to predict drilling force (Fz) and torque (Tc) for optimal drilling conditions. The model is a helping tool to select operational parameters for the material to cut by providing the programmer predicted drilling forces (Fz) and torque (Tc) values. This will allow the avoidance of operational parameters that will cause excessively high force and torque values that could damage quality. The model is validated for three types of Gamma-TiAl alloys. Integral hard metal end-drilling tools and different cutting parameters (feeds and cutting speeds) are tested for three different sized holes for each alloy.

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Feng, Shikang, Insung Han, Andrew Lui, Robin Vincent, Gideon Ring, Patrick S. Grant, and Enzo Liotti. "Investigating Metal Solidification with X-ray Imaging." Metals 12, no. 3 (February 24, 2022): 395. http://dx.doi.org/10.3390/met12030395.

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In the last two decades, X-ray imaging techniques have been used increasingly to study metal solidification in real-time as, thanks to advances in X-ray sources (synchrotron and laboratory-based) and detector technology, images can now be obtained with spatio-temporal resolutions sufficient to record key phenomena and extract quantitative information, primarily relating to crystal growth. This paper presents an overview of the research conducted at the University of Oxford over the last 6 years as a partner in the UK’s Future Liquid Metal Engineering (LiME) Manufacturing Hub. The focus is on in situ X-ray radiography to investigate the solidification of Al alloys, including the formation of primary α-Al crystals, and the formation and growth of secondary intermetallic phases. Technologically, the thrust is to understand how to control as-cast phases, structures and element distributions, particularly elements associated with recycling, as a means to facilitate greater recirculation of aluminium alloys. We first present studies on refinement of primary α-Al, including extrinsic grain refinement using inoculation and intrinsic refinement based on dendrite fragmentation. Second, we describe studies on intermetallic phase formation and growth, because intermetallic fraction, morphology and distribution are frequently a limiting factor of alloy mechanical properties and recyclability. Then we present some of the latest progress in studying liquid flow during solidification and associated hot tear formation. Finally, future research directions are described.

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Eggert, B. G. F., J. F. H. Belo, J. P. Araújo, B. C. Hauback, and C. Frommen. "Structural transitions and magnetocaloric properties of low-cost MnNiSi-based intermetallics." Intermetallics 154 (March 2023): 107823. http://dx.doi.org/10.1016/j.intermet.2023.107823.

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Illarionov, Anatoliy G., Stepan I. Stepanov, Inna A. Naschetnikova, Artemiy A. Popov, Prasanth Soundappan, K. H. Thulasi Raman, and Satyam Suwas. "A Review—Additive Manufacturing of Intermetallic Alloys Based on Orthorhombic Titanium Aluminide Ti2AlNb." Materials 16, no. 3 (January 20, 2023): 991. http://dx.doi.org/10.3390/ma16030991.

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Titanium alloys based on orthorhombic titanium aluminide Ti2AlNb are promising refractory materials for aircraft engine parts in the operating temperature range from 600–700 °C. Parts made of Ti2AlNb-based alloys by traditional technologies, such as casting and metal forming, have not yet found wide application due to the sensitivity of processability and mechanical properties in chemical composition and microstructure compared with commercial solid-solution-based titanium alloys. In the last three decades, metal additive manufacturing (MAM) has attracted the attention of scientists and engineers for the production of intermetallic alloys based on Ti2AlNb. This review summarizes the recent achievements in the production of O-phase-based Ti alloys using MAM, including the analysis of the feedstock materials, technological processes, machines, microstructure, phase composition and mechanical properties. Powder bed fusion (PBF) and direct energy deposition (DED) are the most widely employed MAM processes to produce O-phase alloys. MAM provides fully dense, fine-grained material with a superior combination of mechanical properties at room temperature. Further research on MAM for the production of critical parts made of Ti2AlNb-based alloys can be focused on a detailed study of the influence of post-processing and chemical composition on the formation of the structure and mechanical properties, including cyclic loading, fracture toughness, and creep resistance.

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44

Silvayeh, Zahra, Bruno Götzinger, Werner Karner, Matthias Hartmann, and Christof Sommitsch. "Calculation of the Intermetallic Layer Thickness in Cold Metal Transfer Welding of Aluminum to Steel." Materials 12, no. 1 (December 22, 2018): 35. http://dx.doi.org/10.3390/ma12010035.

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The intermetallic layer, which forms at the bonding interface in dissimilar welding of aluminum alloys to steel, is the most important characteristic feature influencing the mechanical properties of the joint. In this work, horizontal butt-welding of thin sheets of aluminum alloy EN AW-6014 T4 and galvanized mild steel DC04 was investigated. In order to predict the thickness of the intermetallic layer based on the main welding process parameters, a numerical model was created using the software package Visual-Environment. This model was validated with cold metal transfer (CMT) welding experiments. Based on the calculated temperature field inside the joint, the evolution of the intermetallic layer was numerically estimated using the software Matlab. The results of these calculations were confirmed by metallographic investigations using an optical microscope, which revealed spatial thickness variations of the intermetallic layer along the bonding interface.

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45

Cho, Young Hee, and Arne K. Dahle. "Catalysing Effect of Intermetallic Compounds on Hydrogen Desorption Kinetics in Cast Magnesium Alloys." Materials Science Forum 654-656 (June 2010): 2863–66. http://dx.doi.org/10.4028/www.scientific.net/msf.654-656.2863.

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Magnesium based hydrogen storage materials were prepared by a conventional melting and casting technique. Characterisation of microstructure and hydrogen sorption properties of the alloys was carried out. Additions of Al, Cu and Ni lead to the formation of eutectic mixtures, Mg-Mg17Al12, Mg-Mg2Cu and Mg-Mg2Ni, respectively, with an inter-lamellar spacing of a few hundred nanometers. 3d and 4d transition metals were also added to Mg based alloys and were found to form intermetallic compounds that were homogeneously dispersed in the alloys. The dehydrogenation rate of the Mg alloys was quantitatively analysed in order to determine the rate-limiting step for the hydrogen desorption kinetics. The catalysing role of each intermetallic compound for the hydrogen desorption kinetics is further discussed.

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46

Ioroi, Kazushige, Yasuyuki Kaneno, Satoshi Semboshi, and Takayuki Takasugi. "Effect of transition metal addition on microstructure and hardening behavior of two-phase Ni3Al-Ni3V intermetallic alloys." Materialia 5 (March 2019): 100173. http://dx.doi.org/10.1016/j.mtla.2018.11.022.

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47

Ilayaraja, M., L. John Berchmans, and Sankara Raman Sankaranarayanan. "Preparation of rare earth - transition metal (RE: Y, Tm: Co) intermetallic compounds by calciothermic reduction diffusion process." Metallurgical and Materials Engineering 20, no. 1 (March 31, 2014): 35–40. http://dx.doi.org/10.5937/metmateng1401035i.

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Rare earth cobalt alloys have many special magnetic properties and can be used to prepare magnetic and magneto-optical components. The yttrium – cobalt intermetallic compounds are prepared by calciothermic reduction – diffusion (CRD) process at temperature of 1000ºC, under argon atmosphere. Yttrium oxide, metallic cobalt powder, metallic calcium are used as raw materials in this process. Calcium acts as the reductant, which is used to prepare the YCo5 magnetic material. XRD, SEM, EDAX and some thermodynamic valuation have been carried out on the products. The chemical reactions controlled by unreacted core model theory were studied.

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48

Shukla, S., A. Banas, and R. V. Ramanujan. "Atomistic mechanism of cyclic phase transitions in Nd–Fe–B based intermetallics." Intermetallics 19, no. 8 (August 2011): 1265–73. http://dx.doi.org/10.1016/j.intermet.2011.04.006.

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49

Khimukhin, Sergey N., Sergey V. Nikolenko, L. A. Konevtsov, and E. D. Kim. "Obtaining of Metal-Matrix Alloys Based on Ni-Al for ESD Coatings Formation." Materials Science Forum 1083 (April 6, 2023): 203–9. http://dx.doi.org/10.4028/p-to8w5b.

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The experimental results of obtaining complex-alloyed intermetallic alloys by the method of liquid-phase self-propagating high-temperature synthesis (SHS) and their subsequent use for the formation of wear-resistant coatings by the method of electrospark deposition (ESD) are submitted. Metal oxides Cr2O3, NiO, CoO and mineral concentrate containing a larger part of ZrO2 in its composition were used as a melt charge for the SHS experiments. Alloys based on Ni-Al system dopped with Cr, Zr, Co, and C were obtained. It was established that extra addition of C led to the refinement of the alloys microstructure (3-5 times). ESD coatings were formed on steel 45 using the obtained alloys as anode material. The coatings formed by using the alloys doped by Co, Zr, Cr and extra addition of C (0.4 wt%) proved to be maximum wear resistant.

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50

Kartsev, Alexey, Peter V. Lega, Andrey P. Orlov, Alexander I. Pavlov, Svetlana von Gratowski, Victor V. Koledov, and Alexei S. Ilin. "Phase Transformation in TiNi Nano-Wafers for Nanomechanical Devices with Shape Memory Effect." Nanomaterials 12, no. 7 (March 28, 2022): 1107. http://dx.doi.org/10.3390/nano12071107.

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Recently, Ti-Ni based intermetallic alloys with shape memory effect (SME) have attracted much attention as promising functional materials for the development of record small nanomechanical tools, such as nanotweezers, for 3D manipulation of the real nano-objects. The problem of the fundamental restrictions on the minimal size of the nanomechanical device with SME for manipulation is connected with size effects which are observed in small samples of Ti-Ni based intermetallic alloys with thermoplastic structural phase transition from austenitic high symmetrical phase to low symmetrical martensitic phase. In the present work, by combining density functional theory and molecular dynamics modelling, austenite has been shown to be more stable than martensite in nanometer-sized TiNi wafers. In this case, the temperature of the martensitic transition asymptotically decreases with a decrease in the plate thickness h, and the complete suppression of the phase transition occurs for a plate with a thickness of 2 nm, which is in qualitative agreement with the experimental data. Moreover, the theoretical values obtained indicate the potential for even greater minimization of nanomechanical devices based on SME in TiNi.

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Journal articles on the topic 'Transition Metal Based Intermetallic Alloys'

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