Computational materials science: Substitution with vision

A method has been developed for predicting the stability and elasticity of certain alloys for millions of atomic configurations of the materials. This approach should help to identify materials with optimized properties. See Letter p.740 This study asks a fundamental question: is the most thermodynamically stable atomic configuration of a material the hardest, stiffest or strongest form of that material? Or could some metastable configurations improve on that performance? Focusing on stiffness, the authors perform first-principles calculations on a huge configuration space of four different binary-alloy systems. They find that, at least in the systems they research, stiffness and heat of formation are negatively and linearly correlated. That is, the more stable a system is, the harder the material will be. The methods used here should, in principle, be applicable to the investigation of other relationships between stability and mechanical properties.