The thermal cycling method induces structural defects to enhance the mechanical properties of FeGa alloys

Abstract

The substantial improvement of mechanical properties in magnetostrictive alloys always accompanies the sacrifice of magnetic properties, limiting the potential applications in the fields involving precision drives and intelligent sensing, etc. In this paper, we proposed a novel thermal cycling method to enhance the mechanical properties of FeGa alloys without affecting the magnetic properties as much as possible. Specifically, the hardness raised from 4.90 GPa to 5.43 GPa, and the elastic modulus increased by 28.16% after 30-times thermal cycling treatments, accompanied by the initial permeability of specimens slightly dropping from 52.47 × 10−3 Oe g/emu to 50.16 × 10−3 Oe g/emu. The significant improvement in the mechanical properties of FeGa alloys was mainly attributed to the appearance of stacking faults and twins, which were caused by a sharp decrease in the stress between adjacent lattices. Meanwhile, the weakening of magnetic properties in FeGa alloys was associated with obstacles in magnetic domains. The proposed thermal cycling method would provide a substantial basis for developing novel FeGa alloys with more desirable physical properties.