Phase-field simulation of α-Mg dendrite growth in magnesium alloys: A review

Magnesium alloys, as typical hexagonal close-packed (hcp) structural metals, exhibit complex and diverse morphological characteristics of α-Mg dendrite in their as-cast microstructures, which significantly influence component performance. The formation of α-Mg dendrite stems from the instability of the solid-liquid interface during solidification—an intricate synergy among heat-mass transfer, momentum transport, interface curvature effects, and crystalline anisotropy. The phase-field method (PFM), employing a continuous order parameter to characterize phase transitions, effectively circumvents explicit tracking of the solid-liquid interface through its diffuse-interface characteristics. This review systematically elaborates on the morphological features of α-Mg dendrite and summarizes phase-field modeling approaches for their growth dynamics. Furthermore, it synthesizes recent advances in phase-field simulations of α-Mg dendrite growth during magnesium alloy solidification across multiple dimensions, including: multiphysics coupling, multiphase coupling, macro-microscale coupling, integration with synchrotron radiation characterization, directional solidification, and additive manufacturing. Finally, the critical advantages and existing limitations of the PFM in this field are evaluated, and future research directions are proposed. • Phase-field methods achieve accurate simulation of complex growth morphology of α-Mg dendrites through diffusion interface characteristics and interface energy anisotropy function, avoiding the difficulty of explicit interface tracking. • α-Mg dendrites exhibit a sixfold symmetric branch structure on the ( 0001 ) basal plane, and primary arms grow along 11 2 ̅ 0 direction. Their morphology is controlled by composition, cooling rate, and temperature gradient. • Multi-dimensional research integrates multi-physical field coupling, macro-micro scale correlation, and synchrotron radiation technology to deepen the understanding of the α-Mg dendritic growth mechanism and promote quantitative prediction.