Fabrication, high-temperature mechanical behavior, and oxidation resistance of high entropy alloys: A review

Abstract

High entropy alloys (HEAs), as a new type of alloy, have attracted increasing attention since it was developed in 2004, showing high engineering potential in various fields. This paper provides a comprehensive review of the recent progress in their fabrication, high-temperature mechanical behavior, and oxidation resistance. It begins with an introduction of the effects of intrinsic characteristics of HEAs on their physical properties, focusing on the four typical effects including the high-entropy effect, the sluggish diffusion effect, the severe lattice effect, and the cocktail effect. Fabrication methods of HEA feeding powders, HEA blocks, and HEA coatings are then analyzed from the methodologies to mechanical properties. Afterward, the recent progress of FeCoCrNiAlTi HEAs and refractory HEAs which both demonstrated excellent mechanical properties at high temperatures is discussed with the underlying mechanisms, such as the chemical composition effect, the phase structure effect, and the strengthening effect. Recent antioxidant strategies including the formation of Al oxides, Cr oxides, and Si oxides in HEAs are highlighted. This review is concluded with prospects on challenges and future directions in the critical fields, such as their fundamental applications and design strategies of advanced HEAs with good high-temperature performance.