A phase field formulation of microstructure evolution induced by laser-based additive manufacturing with atomic defect generation

Abstract

A phase field formulation of microstructure evolution during laser powder-bed additive manufacturing process is presented taking into account coupled heat transfer, stress effects and atomic defects (vacancies and interstitials) generation at the moving liquid-solid interface. A kinetic equation for the phase field coupled to the temperature, the concentration of atomic defects, and the elastic displacement fields is derived based on first and second laws of thermodynamics. The phenomenon of flexural instability with the PD clustering (formation of micropores and dislocation loops) and its effect on the exfoliation of deposited layers on a substrate are also discussed.