(111)-orientation growth of Tb-Dy-Fe alloys induced by high magnetic fields during directional solidification

The (110) and (112) directions are the preferred growth directions of the magnetic phase in Tb-Dy-Fe alloys, but the (111) direction is the easy magnetization axis direction, and the (111)-oriented alloy exhibits superior magnetostrictive behavior. In this study, Tb-Dy-Fe alloys with (111) orientation were prepared by directional solidification (i.e., the master alloy was completely melted) under high magnetic fields. The competition between the preferred growth direction and the easy magnetization direction was resolved, leading to enhanced magnetostrictive properties. During the initial solidification stage, the magnetic torque induced the (111) orientation in the magnetic phases generated by direct precipitation of the liquid phase and pseudo-eutectic reactions to rotate in the direction of the magnetic field. In the subsequent competitive growth process, (111)oriented grains grew parallel to the magnetic field direction under the influence of magnetocrystalline anisotropy energy. This work enriches the theory of magnetic orientation during directional solidification, providing novel insights into the preparation of highly oriented functional materials.