Phase separation and improved plasticity by modulated heterogeneity in Cu–(Zr, Hf)–(Gd, Y)–Al metallic glasses

The effect of replacement of Zr/Hf with Gd or Y in Cu46Zr47Al7 and Cu50Hf42.5Al7.5 alloys has been investigated. Phase separation into Cu–Gd-rich (or Cu–Y-rich) and Cu–Zr-rich (or Cu–Hf-rich) amorphous phases occurs during cooling when the Gd (or Y) content is above 15 at.% in Cu–(Zr, Hf)–(Gd, Y)–Al alloys. In particular, it was realized that the plasticity in bulk metallic glass with heterogeneity can be enhanced either by tailoring the combinations of the constituent elements or by controlling the cooling rate.