Phase-field modeling of the grain growth of NiTi shape memory alloys during additive manufacturing process

The prediction of the equilibrium and metastable phase/grain morphologies during selective laser melting (SLM) of NiTi shape memory alloys can be accomplished using phase-field (PF) modeling. In the current research, a model for binary and multi-component systems is utilized and validated via the steady-state growth problem with a comparison to theoretical predictions of the Green-function calculations and the Kurz–Fisher model. By means of the PF simulations, a phenomenological dependency of the growth velocity on undercooling during the rapid solidification is evaluated. The final microstructures predicted by the PF are in good agreement with the experimental observations. The developed microstructures in this research will be used as representative volume elements (RVEs) for crystal plasticity simulation to investigate the microstructure evolution of the alloys during cyclic loading in meso-scale.