The calculation of interfacial free energies via λ integration

Abstract

The development of methods for the accurate calculation of interfacial free energies would have important consequences for predicting the mechanical and thermodynamic behavior of metals and other materials. For example, the passage of a dislocation through crystals is accompanied by the formation of various extended defects, such as stacking faults and antiphase boundaries. The associated formation energies influence the mobility of the dislocation and distinguish between slip systems and thus greatly affect the mechanical properties of metals and alloys. Also, nucleation theory relates the rate of precipitate formation to the interfacial free energy between the two phases, thus controlling the thermodynamic stability of solid solutions. This article discusses the general problem in calculating interfacial free energies in solids and describes a new method for antiphase boundaries and chemically disordered systems: simulated alchemy. Sample calculations for the APB on the (111) face of Ni3Al are given using a Finnis-SincIair-type potential.