The effect of Hf substitution for Zr on glass forming ability and magnetic property of FeCoZrMoBAlY bulk metallic glasses

Bulk metallic glasses (BMGs) Fe61Co6Zr8-xHfxMo7B15Al1Y2 (x = 0-8) have been produced by copper mold casting technique using industrial raw materials. The effect of substitution of Hf for Zr on the glass forming ability (GFA) and the magnetic property has been studied by Xray diffraction (XRD), differential scanning calorimetry (DSC) and superconducting quantum interference device (SQUID). It was found that the substitution of an appropriate amount of Hf for Zr can improve the GFA of the base alloy Fe61Co6Zr8Mo7B15Al1Y2, as demonstrated by the increase in reduced glass transition temperature T-rg (=T-g/T-l) and GFA parameters of gamma (=T-x/T-g + T-l) and delta (=T-x/T-l - T-g). The Fe61Co6Zr5Hf3Mo7B15Al1Y2 alloy exhibits the highest GFA with the largest T-rg (0.612) and delta (1.633), and can cast a fully amorphous rod in 3 mm diameter. The substitution of Hf for Zr also enhances the magnetic properties, as verified by the increase in saturation magnetization (M-s) in the alloy of Fe61Co6Zr3Hf5Mo7B15Al1Y2, whose M, is approximately 1.5 times higher than that of the base alloy (x = 0) at room temperature. Finally, the effect of the substitution of Hf for Zr on glass forming ability and magnetic properties is discussed. (c) 2007 Elsevier B.V. All rights reserved.