Phase-field simulation of effects of normal strain on the morphology and kinetics evolution of nanoscale phase

Abstract

This is the first investigation on the morphology and kinetics evolution of nanoscale precipitates under normal strain with the three-dimensional phase-field simulation. The volume fraction, particle number density and average particle radius of the precipitates are clarified for uniaxial, biaxial and triaxial strain, combining the free energy and shape change of nanoscale precipitates. For the anisotropic elasticity, uniaxial, biaxial and triaxial strain promote phase decomposition compared with strain-free state, except that triaxial compressive strain retards the early-stage precipitation. Nanoscale precipitates under mixed biaxial or triaxial strain display strip-like shape, especially for the biaxial tensile with uniaxial compressive strain. Triaxial tensile and compressive strain do not change the shape of precipitates, while the particle size is reduced under triaxial compressive strain. The results demonstrate that normal strain affects the morphology and kinetics of the nanoscale phase to different degrees.