Superhigh strength and good soft-magnetic properties of (Fe, Co)-B-Si-Nb bulk glassy alloys with high glass-forming ability

摘要

Fe-based bulk ferromagnetic glassy alloys with diameters up to 5 mm were formed in [(Fe_(1-x)Co_(x))_(0.75)B_(0.2)Si_(0.05)]_(96)Nb_(4) system by the copper mold casting method. The substitution of Co for Fe caused an increase of glass-forming ability as well as an improvement of mechanical and magnetic properties. The bulk glassy alloys exhibited superhigh fracture strength of 3900-4250 MPa, Young's modulus of 190-210 GPa, elastic strain of 0.02, and plastic strain of 0.0025. The bulk glassy alloys also exhibited good soft magnetic properties, i.e., saturation magnetization of 0.84-1.13 T, low coercive force of 1.5-2.7 A/m, high permeability exceeding 1.2×10~(4), and Curie temperature of 600-690 K.