1 - A brief history of alloys and the birth of high-entropy alloys

Abstract

Alloys have helped and defined the march of civilization for over five millennia. The progress from native metals and native alloys to the accidental discovery of arsenical bronzes is a remarkable story. Numerous combinations of alloying elements were tried usually based on one principal element. Higher amounts of alloying were also used in alloys such as high-tin bronzes and ultrahigh-carbon steels. From such concentrated binary alloys to multicomponent alloys marked a major advance resulting in alloy steels and superalloys in the last century. Nevertheless, there was one metal element in major proportion in all these alloys. A revolutionary step in alloying occurred in 2004 when Jien-Wei Yeh and Brian Cantor independently reported multicomponent equiatomic or near-equiatomic alloys. Surprisingly, many of these alloys turned out to be solid solutions similar to the bronzes of the third-millennium BCE. They have breathed new life into material world promising an extraordinarily rich family of alloys.