Controlling grain boundary mobility in phase-field-crystal model

Abstract

Grain boundary (GB) mobility is a key parameter in modelling microstructure evolution of polycrystalline materials. It is well known that GB mobility depends on the misorientation and possibly other degrees of freedom of the GB. This misorientation dependence has been calculated in numerous previous studies using molecular dynamics (MD) for several materials. However, MD simulations are computationally demanding due to need to account for atomic fluctuations, where the recently developed phase-field-crystal (PFC) method is shown to overcome this shortcoming. Nonetheless, GB mobility was not extensively studied using PFC, and it is not clear if the mobility in the PFC method has a similar misorientation dependency as the one extracted from the MD simulation. This work addresses this issue by calculating the GB mobility for several GBs in Nickel using both the MD simulation and the PFC. It is found that the misorientation dependent GB mobility in the PFC follow similar behavior as in the MD results when the kinetic factor is tuned to depend on the local-averaged density order parameter in the PFC model.