Revealing interfacial anisotropy effects on dendritic growth in zinc alloys: a phase-field study

• Anisotropy of interfacial energy and dendrite morphology in Zn alloys. • Anisotropy coefficient a 0 6 in spherical harmonics is essential. • Anisotropy coefficients should be evaluated from growth morphology. Reliable data on solid–liquid interfacial properties for Zn alloys remain critically lacking. Time-resolved X-ray computed tomography at a large-scale synchrotron facility revealed dendritic morphologies growing in 14 directions, which cannot be adequately described solely by the interfacial energy anisotropy coefficients a 0 2 , a 0 4 , and a 6 6 based on spherical harmonics. To address this limitation, we introduce the coefficient a 0 6 . Phase-field simulations of equiaxed dendritic growth in a Zn–4 wt%Al alloy are performed while systematically varying the anisotropy coefficients. The results demonstrate that incorporating a 0 6 is essential to reproduce dendrite growth along 14 directions. Moreover, the relationship between equilibrium shapes and anisotropy coefficients shows that the effects of a 0 4 , a 0 6 , and a 6 6 are not readily evaluated from shapes experimentally obtained in pursuit of equilibrium, emphasizing the need to analyze growth morphologies to determine these coefficients accurately.