Effect of Ta Addition on Glass-Forming Ability and Structures of Fe40Co40Zr7V2B11 Alloy

Fe40Co40Zr7V2B11-xTax (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.