A phase-field model was developed in order to study stress-driven grain boundary migration in elastically inhomogeneous polycrystalline materials with arbitrary elastic inhomogeneity and anisotropy. The dependence of elastic stiffness tensor on grain orientation was taken into account, and the elastic equilibrium equation was solved using the Fourier spectral iterative-perturbation method. The migration of planar and curved grain boundaries under an applied stress was studied. The relationship between grain boundary migration velocity and driving force was found to be linear in the steady-state regime. The study showed that the stress distribution depended upon the relative misorientation between the grains, and the nature of the applied load. As a consequence, the mechanism of grain boundary migration was different when the load was applied parallel or perpendicular to a grain boundary. The bulk mechanical driving force for grain boundary migration was provided by the difference in the level of stress in the adjoining grains which arose due to difference in elastic moduli. It was also shown that, under certain conditions, an applied stress could act as a precursor to abnormal grain growth.

A Phase-Field Model of Stress Effect on Grain Boundary Migration. S.Bhattacharyya, T.W.Heo, K.Chang, L.Q.Chen: Modelling and Simulation in Materials Science and Engineering, 2011, 19[3], 035002