Refractory high-entropy alloys fabricated by powder metallurgy: Progress, challenges and opportunities

Refractory high-entropy alloys, which involve the mixing of four or more refractory metal elements in an equiatomic or near-equiatomic ratio, hold significant potential for various applications in high-temperature materials fields. This is mainly due to their stable phase structure and excellent high-temperature properties. While considerable interest has been in these alloys, most of them have been developed using melting casting technology. However, powder metallurgy has emerged as a promising alternative for further advancement in this field. It has the potential to expand the application areas and enhance the properties of these alloys. This article introduces to various techniques for fabricating pre-alloyed refractory high-entropy powders and their densification. Additionally, it reviews the methods for regulating the microstructure and properties of powder metallurgy refractory high-entropy alloys.