Phase field microelasticity model of dislocation climb: Methodology and applications

We develop a dislocation climb model based on a phase field description that couples non-conservative dislocation motion and vacancy diffusion. A reaction-diffusion model is incorporated where vacancy transport is governed by the Cahn-Hilliard equation, while the binding of vacancies to dislocation cores is described as adsorptive reaction. The model extends the previously developed phase field microelasticity theory of dislocations to consider the osmotic force associated with non-equilibrium vacancy concentration. We first present quantitative validations of diffusion-controlled and quasi-steady-state dislocation climb with and without dislocation-vacancy interaction. The capability of the model is then demonstrated by simulations of Nabarro diffusional creep and the Kirkendall effect, both showing excellent agreement with classical descriptions of dislocation climb plasticity and interdiffusion. Straightforward applications to irradiation and climb-dominated deformation of crystals are possible, as long as multiple climb systems and vacancy thermodynamic databases are taken into account.