Abstract:
All human advances have depended on making new materials, and all materials are alloys, i.e. mixtures of several different starting materials or components. So the history of the human race has been the continued invention of new materials by discovering new alloys. Recently a new way of doing this, by manufacturing multicomponent high-entropy alloys, has shown that the total number of possible materials is enormous, so we have lots of wonderful new materials yet to find. And multicomponent phase space contains a surprisingly large number of single-phase extended solid solutions and compounds. The first of these that was discovered are called Cantor alloys, an enormous composition range with a single-phase fcc structure, based on the original equiatomic five-component Cantor alloy CrMnFeCoNi. This talk discusses the history of alloying, the discovery of multicomponent alloys, the structure of multicomponent phase space, the thermodynamics of multicomponent solid solutions such as the Cantor alloys, the complexity of local atomic and nanoscale configurations in such materials, the effect on properties such as atomic diffusion, dislocation slip, recrystallisation and surface catalysis, and the resulting outstanding mechanical properties and potential applications, including at low and high temperatures, for corrosion and radiation resistance, and to enhance recycling and re-use.