High-entropy alloys were once thought to owe their exceptional properties to complete chemical disorder, but advances over the past decade revealed that subtle forms of atomic order are widespread and often essential. Recognizing how order and disorder work together is now reshaping alloy design and opening new routes to stronger, tougher and more reliable materials.
High-entropy alloys (HEAs), or more broadly multi-principal element alloys and complex concentrated alloys, entered the materials landscape two decades ago with a bold and deceptively simple proposition that multi-component, equiatomic, chemically disordered solid solutions might yield unprecedented combinations of strength, ductility and stability. For many years, ‘high entropy’ became synonymous with randomness and configurational stabilization, reinforcing the belief that chemical disorder was both defining and inherently beneficial.
Over the past decade, however, this picture has been fundamentally revised. A growing body of experimental and computational work now shows that HEAs host rich, pervasive chemical inhomogeneities across multiple length scales, from sub-nanometre to tens of nanometres1,2,3,4. It has become increasingly clear that the interplay between chemical order and disorder, rather than the latter alone, governs the outstanding behaviour of HEAs. In this Comment, I highlight the advances that have revealed this hidden chemical complexity and outline opportunities for future alloy design.
Link:Order or disorder, that is the question in high-entropy alloys | Nature Reviews Materials
