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. (Ti33Zr33Hf33)90−x(Ni50Cu50)xAl10, (Ti33Zr33Hf33)90−x(Ni33Cu33Ag33)xAl10, (Ti25Zr25Hf25Nb25)90−x(Ni50Cu50)xAl10 and (Ti25 Zr25Hf25Nb25)90−x(Ni33Cu33Ag33)xAl10 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 (Ti33Zr33Hf33)90−x(Ni50Cu50)xAl10 and (Ti25Zr25Hf25Nb25)90−x(Ni50Cu50)xAl10 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 (Ti33Zr33Hf33)40(Ni50Cu50)50Al10 with a crystallisation temperature of Tx=545 °C. Addition of Ag decreased the composition range of the amorphous phase to x=20–40 at.% for the (Ti33Zr33Hf33)90−x(Ni33Cu33Ag33)xAl10 and (Ti25Zr25Hf25Nb25)90−x(Ni33Cu33Ag33)xAl10 alloys. However the amorphous alloy with the largest supercooled liquid region was (Ti33Zr33Hf33)50(Ni33Cu33Ag33)40Al10 with a crystallisation–glass transition temperature difference of Tx−Tg=103 °C.