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)(x)Al-10, (Ti33Zr33Hf33)(90-x)(Ni33Cu33Ag33)(x)Al-10, (Ti25Zr25Hf25Nb25)(90-x)(Ni50Cu50)(x)Al-10 and (Ti25Zr25Hf25Nb25)(90-x)(Ni33Cu33Ag33)(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 (Ti33Zr33Hf33)(90-x)(Ni50Cu50)(x)Al-10 and (Ti25Zr25Hf25Nb25)(90-x)(Ni50Cu50)(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 (Ti33Zr33Hf33)(40)(Ni50Cu50)(50)Al-10 with a crystallisation temperature of T-x = 545 degreesC. Addition of Ag decreased the composition range of the amorphous phase to x = 20-40 at.% for the (Ti33Zr33Hf33)(90-x)(Ni33Cu33Ag33)(x)Al-10 and (Ti25Zr25Hf25Nb25)(90-x)(Ni33Cu33Ag33)(x)Al-10 alloys. However the amorphous alloy with the largest supercooled liquid region was (Ti33Zr33Hf33)(50)(Ni33Cu33Ag33)(40)Al-10 with a crystallisation-glass transition temperature difference of T-x - T-g = 103 degreesC. (C) 2003 Elsevier Science B.V. All rights reserved.