Metallic glass formation in multicomponent (Ti, Zr, Hf, Nb)–(Ni, Cu, Ag)–Al alloys

A wide range of novel multicomponent amorphous alloys have been manufactured by a new method of equiatomic substitution for the early and late transition metals in Zr-based amorphous alloys. (Ti 33Zr 33Hf 33) 90− x (Ni 50Cu 50) x Al 10, (Ti 33Zr 33Hf 33) 90− x (Ni 33Cu 33Ag 33) x Al 10, (Ti 25Zr 25Hf 25Nb 25) 90− x (Ni 50Cu 50) x Al 10 and (Ti 25 Zr 25Hf 25Nb 25) 90− x (Ni 33Cu 33Ag 33) x Al 10 alloys with composition range x=20–70 at.% have been prepared by melt-spinning and the range of glass formation characterized by X-ray diffraction and differential scanning calorimetry. Amorphous alloys were formed over the composition range x=20–70 at.% for the (Ti 33Zr 33Hf 33) 90− x (Ni 50Cu 50) x Al 10 and (Ti 25Zr 25Hf 25Nb 25) 90− x (Ni 50Cu 50) x Al 10 alloys. Addition of Nb with a higher melting point than Ti, Zr and Hf increased the thermal stability of the amorphous phase for the whole composition range x=20–70 at.%. The most stable amorphous alloy was (Ti 33Zr 33Hf 33) 40(Ni 50Cu 50) 50Al 10 with a crystallisation temperature of T x =545 °C. Addition of Ag decreased the composition range of the amorphous phase to x=20–40 at.% for the (Ti 33Zr 33Hf 33) 90− x (Ni 33Cu 33Ag 33) x Al 10 and (Ti 25Zr 25Hf 25Nb 25) 90− x (Ni 33Cu 33Ag 33) x Al 10 alloys. However the amorphous alloy with the largest supercooled liquid region was (Ti 33Zr 33Hf 33) 50(Ni 33Cu 33Ag 33) 40Al 10 with a crystallisation–glass transition temperature difference of T x − T g=103 °C.