Mechanical Properties of Random Alloys from Quantum Mechanical Simulations

Today, a direct determination of the mechanical properties of complex alloys from first-principles theory is not feasible. On the other hand, well established phenomenological models exist, which are suitable for an accurate description of materials behavior under various mechanical loads. These models involve a large set of atomic-level physical parameters. Unfortunately, in many cases the available parameters have unacceptably large experimental error bars. Here we demonstrate that computational modeling based on modern first-principles alloy theory can yield fundamental physical parameters with high accuracy. We illustrate this in the case of aluminum and transition metal alloys and austenitic stainless steels by computing the size and elastic misfit parameters, and the surface and stacking fault energies as functions of chemical composition.