Production of amorphous CoSiB and CoMSiB (M ≡ Group IV – VIII transition metals) wires by a method employing melt spinning into rotating water and some properties of the wires

Abstract

Continuous amorphous wires with a high strength and a good ductility were produced in the CoSiB alloy system by a technique using melt spinning into rotating water. The wires have a circular cross section and a smooth peripheral surface. Their diameters are in the range 0.08 – 0.14 mm. The Vickers hardness H V and tensile strength σ f are of the order of 1050 – 1230 HDP and 2750 – 3580 MPa respectively, which exceed the corresponding values of heavily cold-drawn steels. Young's modulus E is about 1.23 × 10 5 MPa and the fracture elongation ϵ f is about 2.1% – 3.0%. Cold drawing to about 50% reduction in area results in increases in σ f, E and ϵ f by about 3.7%, 8.7% and 53% respectively. The increase in σ f is interpreted as originating from the interaction between the pre-existing deformation bands introduced by cold drawing and the increase in the uniformity of shape by drawing. Further, σ f, H V and T x for Co 72.5Si 12.5B 15 amorphous wire increase significantly on the replacement of cobalt with tantalum, niobium, vanadium or chromium without detriment to the good bending ductility. The highest values of σ f, H V and T X obtained are about 4000 MPa, 1190 HDP and 873 K for the (Co 95Ta 5) 72.5Si 12.5B 15 wire drawn to about 50% reduction.