Complex hexagonal close-packed dendritic growth during alloy solidification by graphics processing unit-accelerated three-dimensional phase-field simulations: demo for Mg–Gd alloy

In this study, insights into the effect of interfacial anisotropy on a complex hexagonal close-packed (hcp) dendritic growth during alloy solidification were gained by graphics processing unit (GPU)-accelerated three-dimensional (3D) phase-field simulations, as demonstrated for a Mg–Gd alloy. An anisotropic phase-field model with finite interface dissipation was developed by incorporating the contribution of the anisotropy of interfacial energy into the total free energy functional. The modified spherical harmonic anisotropy function was then chosen for the hcp crystal. The GPU parallel computing algorithm was implemented in the present phase-field model, and a corresponding code was developed in the compute unified device architecture parallel computing platform. Benchmark tests indicated that the calculation efficiency of a single TESLA V100 GPU could be ~ 80 times that of open multi-processing (OpenMP) with eight central processing unit cores. By coupling the phase-field model with reliable thermodynamic and interfacial energy descriptions, the 3D phase-field simulation of α-Mg dendritic growth in the Mg–6Gd (in wt%) alloy during solidification was performed. Various two-dimensional dendrite morphologies were revealed by cutting the simulated 3D dendrite along different crystallographic planes. Typical sixfold equiaxed and butterflied microstructures observed in experiments were well reproduced. Graphical abstract