Preferred orientation transition mechanism of faceted-growth materials with FCC structure: Competitive advantage depends on 3D microstructure morphologies

We investigated the three-dimensional microstructure morphologies of faceted-growth materials with face-centered cubic structure in the twin-related growth mode. Based on the twin-related growth mode, we obtained the total of five morphology configurations for [101]- and [112]-oriented grains, three of which were identified by our experimental studies in Tb_0.3Dy_0.7Fe_1.95 alloys. The [101]- and [112]-oriented grains exhibit different morphological transition processes and, accordingly, different spatial occupation capacities, eventually leading to the transition of axially preferred orientation during directional solidification.