Low-Density, Refractory Multi-Principal Element Alloys of the Cr-Nb-Ti-V-Zr System: Microstructure and Phase Analysis (Postprint)
TL;DR: In this paper, the crystal structure, microstructure, density and Vickers hardness of four multi-principal element alloys, NbTiVZr, CrNbTiZr and NbVZR, are reported.
About: This article is published in Acta Materialia.The article was published on 2013-03-01. It has received 445 citations till now. The article focuses on the topics: Laves phase & Alloy.
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TL;DR: High entropy alloys (HEAs) are barely 12 years old as discussed by the authors, and the field has stimulated new ideas and inspired the exploration of the vast composition space offered by multi-principal element alloys.
4,693 citations
TL;DR: In this article, a review of critical aspects of high-entropy alloys, including core effects, phases and crystal structures, mechanical properties, high-temperature properties, structural stabilities, and corrosion behaviors are discussed.
Abstract: High-entropy alloys (HEAs) are alloys with five or more principal elements. Due to the distinct design concept, these alloys often exhibit unusual properties. Thus, there has been significant interest in these materials, leading to an emerging yet exciting new field. This paper briefly reviews some critical aspects of HEAs, including core effects, phases and crystal structures, mechanical properties, high-temperature properties, structural stabilities, and corrosion behaviors. Current challenges and important future directions are also pointed out.
2,005 citations
Cites background from "Low-Density, Refractory Multi-Princ..."
...Although the accuracy of computational phase predictions for other HEA systems (other than Al–Co–Cr–Cu–Fe–Ni) is still not clear (the only result appears to be not as pleasing [54]), it is greatly expected that these techniques will become important tools for the future design and development of HEAs....
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TL;DR: In this paper, a critical review of the recent studies aiming to address the fundamental issues related to phase formation in high-entropy alloys is provided, and novel properties of HEAs are also discussed, such as their excellent specific strength, superior mechanical performance at high temperatures, exceptional ductility and fracture toughness at cryogenic temperatures, superparamagnetism and superconductivity.
1,494 citations
TL;DR: This work examines an equiatomic medium-entropy alloy containing only three elements, CrCoNi, as a single-phase face-centred cubic solid solution, which displays strength-toughness properties that exceed those of all high-ENTropy alloys and most multi-phase alloys.
Abstract: High-entropy alloys are an intriguing new class of metallic materials that derive their properties from being multi-element systems that can crystallize as a single phase, despite containing high concentrations of five or more elements with different crystal structures. Here we examine an equiatomic medium-entropy alloy containing only three elements, CrCoNi, as a single-phase face-centred cubic solid solution, which displays strength-toughness properties that exceed those of all high-entropy alloys and most multi-phase alloys. At room temperature, the alloy shows tensile strengths of almost 1 GPa, failure strains of ∼70% and KJIc fracture-toughness values above 200 MPa m(1/2); at cryogenic temperatures strength, ductility and toughness of the CrCoNi alloy improve to strength levels above 1.3 GPa, failure strains up to 90% and KJIc values of 275 MPa m(1/2). Such properties appear to result from continuous steady strain hardening, which acts to suppress plastic instability, resulting from pronounced dislocation activity and deformation-induced nano-twinning.
1,101 citations
TL;DR: In this article, the authors reviewed open literature publications on refractory high entropy alloys (RHEAs) and refractor complex concentrated alloys(RCCAs) in the period from 2010 to the end of January 2018.
Abstract: Open literature publications, in the period from 2010 to the end of January 2018, on refractory high entropy alloys (RHEAs) and refractory complex concentrated alloys (RCCAs) are reviewed. While RHEAs, by original definition, are alloys consisting of five or more principal elements with the concentration of each of these elements between 5 and 35 at.%, RCCAs can contain three or more principal elements and the element concentration can be greater than 35%. The 151 reported RHEAs/RCCAs are analyzed based on their composition, processing methods, microstructures, and phases. Mechanical properties, strengthening and deformation mechanisms, oxidation, and corrosion behavior, as well as tribology, of RHEA/RCCAs are summarized. Unique properties of some of these alloys make them promising candidates for high temperature applications beyond Ni-based superalloys and/or conventional refractory alloys. Methods of development and exploration, future directions of research and development, and potential applications of RHEAs are discussed.
778 citations
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TL;DR: A new approach for the design of alloys is presented in this paper, where high-entropy alloys with multi-principal elements were synthesized using well-developed processing technologies.
Abstract: A new approach for the design of alloys is presented in this study. These high-entropy alloys with multi-principal elements were synthesized using well-developed processing technologies. Preliminary results demonstrate examples of the alloys with simple crystal structures, nanostructures, and promising mechanical properties. This approach may be opening a new era in materials science and engineering.
8,175 citations
TL;DR: In this article, the factors of the atomic size difference Delta and the enthalpy of mixing ΔH mιx of the multi-component alloys were summarized from the literatures.
Abstract: The factors of the atomic size difference Delta and the enthalpy of mixing ΔH mιx of the multi-component alloys were summarized from the literatures. The formation zones of solid-solution phases, intermediate phases, and bulk metallic glasses were determined and the validity was verified by experimental results. For forming the solid solution, the alloys should have high entropy of mixing, lower Delta, and not too negative and positive enthalpy of mixing.
1,936 citations
TL;DR: In this paper, two refractory high entropy alloys with compositions near Nb25Mo25Ta25W25 and V20Nb20Mo20Ta20W20, were produced by vacuum arc-melting.
1,863 citations
TL;DR: In this article, two refractory high-entropy alloys with nearequiatomic concentrations, WNB-Mo-Ta and WBMCV, were produced by vacuum arc melting and the lattice parameters were determined with high-energy X-ray diffraction using a scattering vector length range from 0.7 to 20A−1.
1,655 citations
TL;DR: In this paper, the authors consider a large number of alliages a haute entropie (AHE) which are characterized by a large amount of microstructures and fragiles, e.g., nanocristallines and meme amorphes.
Abstract: Progres recents dans les alliages a haute entropie. La trentaine de systemes d'alliages actuellement d'utilisation courante sont typiquement bases sur un ou, au plus, deux elements. On considerait que des alliages constitues d'un plus grand nombre d'elements principaux formeraient des microstructures compliquees et fragiles, et la recherche sur de tels alliages multielementaires a donc ete tres limitee. Cependant, en 1995, Yeh a suggere que les systemes d'alliages formes d'au moins cinq elements metalliques possedaient des entropies de melange elevees et favoriseraient donc la formation de solutions solides multielementaires, par opposition aux supposees structures complexes formees de nombreux composes intermetalliques. Les travaux effectues au cours de la derniere decennie sur de tels alliages multielementaires, denommes de facon appropriee « alliages a haute entropie » (AHE), ont en effet montre que ces derniers formaient des phases simples a structures nanocristallines et meme amorphes. Outre l'effet de haute entropie, ces caracteristiques structurales ont ete attribuees a l'existence dans ces melanges multielementaires de fortes distorsions de reseau et d'une diffusion ralentie. En fonction de leur composition et du procede d'elaboration, il s'est avere que les AHE presentaient un large spectre de microstructures et de proprietes. Les proprietes superieures de certains AHE par rapport aux alliages classiques, ainsi que le nombre enorme de combinaisons possibles susceptibles de conduire a des phenomenes nouveaux et a des applications fonctionnelles, font que ces AHE presentent un grand interet non seulement du point de vue de la recherche mais aussi pour de nombreuses applications industrielles. Dans cette perspective, cet article passe en revue les progres recents dans les AHE et les orientations futures.
1,288 citations