Ductile Fe-based Amorphous Alloy with Excellent Soft Magnetic Properties Induced by Low-Temperature Stress Annealing

The soft magnetic properties of Fe-based amorphous alloys can be greatly improved by stress relief annealing below its crystallization temperature. However, the structural relaxation during annealing results in the decrease of free volume, which leads to the tough-brittle transition of the alloy. In this work, we successfully reducing the coercivity and brittleness simultaneously by designing a stress annealing strategy where the appropriate tensile force is applied to the longitudinal direction of the ribbon at low annealing temperature and short time. This enables commercial Fe82Si7B11 amorphous alloy to have both a low coercivity of 2.5 A/m and a high ductility, owing to the retention of some of the free volume of the amorphous alloy during low-temperature annealing, the introduction of appropriate tensile force to improve the morphology of magnetic domains, and the reduction of domain wall pinning effects.