Effects of drawing and tension stress annealing on the structure and magnetic properties of Co-based amorphous wire

Abstract

Cold drawing significantly improves the size uniformity of the amorphous wire, but leads to wire curling. Tensile stress annealing (TSA) is the key to regulating the straightness and magnetic properties of Co-based amorphous wires, but their intrinsic correlation is still unclear. Herein, the effects of TSA on the morphology, microstructure, soft magnetic properties and longitudinal driven giant magneto-impedance (LD-GMI) effect of cold drawn Co-based amorphous wires have been studied in detail. It was found that increasing tensile stress can effectively straighten the drawn amorphous wire, yet at the cost of decreasing fracture strength, increasing coercivity and deteriorating GMI effect. Furthermore, appropriate annealing can restore the magnetic properties of the TSA amorphous wire. The variation of magnetic properties is relative to the change of circular anisotropic field and magnetic domain structure.