Effect of Ta Addition on Glass-Forming Ability and Structures of Fe_{40}Co_{40}Zr_{7}V_{2}B_{11} Alloy

Abstract

Fe₄₀Co₄₀Zr₇V₂B_11-xTa_x (x=0, 1, 2) alloy ribbons are prepared through single-roller melt spinning followed by annealing in a temperature range of 300–700°C. The influence of substituting Ta for V on the free and wheel surface structures of the samples is investigated. The addition of Ta improves the glass-formation ability owing to the large atomic radius of Ta atoms. The as-quenched Fe₄₀Co₄₀Zr₇V₂B₁₁ alloy is not amorphous, and α-Fe crystals are textured (200) on the free surface. Moreover, the as-quenched Fe₄₀Co₄₀Zr₇V₂B₁₀Ta₁ alloy is not completely amorphous, and a small amount of α-Fe crystals remains textured (200) on the free surface. The crystallization of the free surfaces of the Fe₄₀Co₄₀Zr₇V₂B₁₁ and Fe₄₀Co₄₀Zr₇V₂B₁₀Ta₁ alloys differs from those of the wheel-contacted surfaces. Both the free and wheel-contacted surfaces of the as-quenched Fe₄₀Co₄₀Zr₇V₂B₉Ta₂ alloy exhibit fully amorphous structures. The crystallization of the free surface of the Fe₄₀Co₄₀Zr₇V₂B₉Ta₂ alloy is similar to that of the wheel-contacted surface. The ductility of the Fe₄₀Co₄₀Zr₇V₂B₉Ta₂ alloy is greater than that of the Fe₄₀Co₄₀Zr₇V₂B₁₁ and Fe₄₀Co₄₀Zr₇V₂B₁₀Ta₁ alloys. The addition of Ta significantly improves the glass-forming ability and ductility of the alloy.