All human advances have depended on making new materials, and all materials are alloys, ie mixtures of several different starting materials or components. The history of the human race has therefore 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, even more than the number of atoms in the galaxy, 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 group of these that was discovered are called Cantor alloys, an enormous composition range with a single-phase fcc structure, based loosely on the original equiatomic five-component Cantor alloy CrMnFeCoNi. This talk will discuss the previous history of alloying, the discovery of multicomponent alloys, the structure of multicomponent phase space, the fundamental thermodynamics of multicomponent solid solutions such as the Cantor alloys, the complexity of local atomic and nanoscale configurations in such materials, the effect of this on properties such as atomic diffusion, dislocation slip, 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.
The topic of the talk is dedicated (highly suitably) to the work of William Hume-Rothery whose famous Hume-Rothery Rules are the basis of all our scientific understanding of alloy and material development.