Enhancement of mechanical properties of Tb0.27Dy0.73Fe1.95 alloy by directional solidification in high magnetic field

The Tb0.27Dy0.73Fe1.95 alloy was prepared using Bridgman-Stockbarge directional solidification under a high magnetic field. The effect of growth velocity and a 6-T magnetic field on the microstructure and mechanical properties of the Tb0.27Dy0.73Fe1.95 alloy was investigated. With increasing growth velocity, the average angle between the growth direction and the long axis of the (Tb, Dy)Fe-3 grains first decreases and then increases, and the width of the (Tb, Dy)Fe-3 phases and the content of the Widmanstatten precipitates decrease gradually. The application of the magnetic field reduces the average angle of the (Tb, Dy)Fe-3 grains; decreases the content of the Widmanstatten precipitates; alters the distribution of Widmanstatten precipitates in the direction nearly parallel to magnetic field direction. Furthermore, the application of the magnetic field increases the fracture strength and strain of the alloys. Such increase can be attributed to the decreases on the average angle of the (Tb, Dy)Fe-3 phases and content of the Widmanstatten precipitates. This study may provide a reference for the application of rare-earth iron-based alloys under a compressive stress.