Glass Forming Ability and Crystallization Behaviour of New Multicomponent (Ti_(33)Zr_(33)Hf_(33))_(60)(Ni_(50)Cu_(50))_(20)Al_(20) Alloy Developed by Equiatomic Substitution

摘要

A new multicomponent alloy developed by equiatomic substitution is studied in terms of glass forming ability and the crystallization behaviour. The glass forming ability of (Ti_(33)Zr_(33)Hf_(33))_(60)(Ni_(50)Cu_(50))_(20)Al_(20) alloy was assessed using the supercooled liquid region and the reduced glass transition temperature, measured by differential scanning calorimetry (DSC) and differential thermal analysis (DTA). The formation of phases with the various wheel speeds from 40 m/s to 15 m/s and the crystallization behaviour was studied by X-ray diffractometry (XRD) and transmission electron microscopy (TEM). The supercooled liquid region and the reduced glass transition temperature were 124°C and 0.525, respectively, measured from the as-quenched (Ti_(33)Zr_(33)Hf_(33))_(60)(Ni_(50)Cu_(50))_(20)Al_(20) ribbons produced with the wheel speed 40 m/s. The as-quenched (Ti_(33)Zr_(33)Hf_(33))_(60)(Ni_(50)Cu_(50))_(20)Al_(20) alloy transformed to nano-sized icosahedral phase during the first exothermic reaction. After crystallization at 700°C, this alloy transformed to hexagonal type Laves phase and Ti_2Ni type phase.