High‐Entropy Alloys: Potential Candidates for High‐Temperature Applications – An Overview

Abstract

Multi-principal elemental alloys, commonly referred to as high-entropy alloys (HEAs), are a new class of emerging advanced materials with novel alloy design concept. Unlike the design of conventional alloys, which is based on one or at most two principal elements, the design of HEA is based on multi-principal elements in equal or near-equal atomic ratio. The advent of HEA has revived the alloy design perception and paved the way to produce an ample number of compositions with different combinations of promising properties for a variety of structural applications. Among the properties possessed by HEAs, sluggish diffusion and strength retention at elevated temperature have caught wide attention. The need to develop new materials for high-temperature applications with superior high-temperature properties over superalloys has been one of the prime concerns of the high-temperature materials research community. The current article shows that HEAs have the potential to replace Ni-base superalloys as the next generation hightemperature materials. This review focuses on the phase stability, microstructural stability, and high-temperature mechanical properties of HEAs. This article will be highly beneficial for materials science and engineering community whose interest is in the development and understanding of HEAs for high-temperature applications.

Pressure-induced phase transition in the AlCoCrFeNi high-entropy alloy

“…High-entropy alloys (HEAs) are a new class of solid solutions containing multi-principal elements (five or more) in equal or near-equal atomic ratios, which have drawn extensive attention in the metallic materials community [1][2][3]. Their unique compositions and atomic structures result in a combination of many superior properties for potential applications, such as high ductility and strength over a wide temperature range, and excellent resistance to wear and corrosion [4][5][6][7][8][9][10][11][12][13][14][15]. Although with complex compositions, HEAs tend to form simple solid solutions with high structural symmetry, e.g., fcc (face-centered cubic), bcc (body-centered cubic), and hcp (hexagonal close-packing) [16].…”

High Entropy Alloys: Ready to Set Sail?

“…However, this might be a too simple and naïve reason. There is no literature on the details of diffusional processes in nano-porous HEA, but many papers have been published on bulk HEA [69], e.g., CoCrFeMnNi [70]. Dezso Beke [71] analyzed the diffusion coefficients of elements in CoCrFeMnNi HEA.…”

Fundamental understanding of mechanical behavior of high-entropy alloys at low temperatures: A review

“…26 What's more important is that the tensile yield strength and ultimate strength, as well as the ductility, are dramatically increased as the temperature reduced from 293 to 77 K. These studies on the low-temperature properties of HEAs give us a new understanding in this area and may provide a great potential on the cryogenic applications of HEAs, such as cryogenic containers and outer space probes. In this case, even though there are several review papers on different aspects of HEAs, [3][4][5]7,[29][30][31][32][33][34][35] it is still necessary for us to have a review on the properties of HEAs at low temperatures since so far no review paper focusing on the low-temperature behaviors of HEAs has been done, and yet there is a great potential for the application of HEAs at cryogenic temperatures.…”