(Co1−xFex)68B21.9Si5.1Nb5 bulk glassy alloys with high glass-forming ability, excellent soft-magnetic properties and superhigh fracture strength

Abstract

The glass-forming ability (GFA), soft-magnetic properties and mechanical properties of (Co1−xFex)68B21.9Si5.1Nb5 (x = 0.1–0.5) glassy alloys were investigated. The (Co1−xFex)68B21.9Si5.1Nb5 glassy alloys exhibit a wide supercooled liquid region of over 40 K, and high reduced glass transition temperatures between 0.603 and 0.648. As a result, the (Co1−xFex)68B21.9Si5.1Nb5 bulk glassy alloys (BGAs) with diameters up to 5.5 mm were produced by copper mold casting. In addition to high GFA, this Co-based glassy alloys exhibit excellent soft-magnetic properties, i.e., saturation magnetization of 0.49–0.91 T, low coercive force of 0.71–1.58 A/m, and high effective permeability of (2.21–3.25) × 104 at 1 kHz under a field of 1 A/m. Besides, this Co-based BGAs also exhibit superhigh fracture strength of 4250–4450 MPa and plastic strain of 0.6–1.3%.