Crystallization Behaviour of Novel (Ti_(33)Zr_(33)Hf_(33))_(100-x)(Ni_(50)Cu_(50))_x Alloys with X= 48 to 55

摘要

Novel (Ti_(33)Zr_(33)Hf_(33))_(100-x)(Ni_(50)Cu_(50))_x alloys with x=48-55 developed by equiatomic substitution are produced by rapid solidification. These multicomponent amorphous alloys show a transition of crystallization mechanism from primary to eutectic crystallization with increasing x. The amorphous alloys with x=48 and 50 transform into a NiTi-type compound and a residual amorphous phase during the first exothermic event indicating the primary crystallization of the NiTi-type phase. In contrast, the amorphous alloys with x=53 and 55 transform into a mixture of NiTi-type and unknown phases during the first exothermic reaction indicating an eutectic crystallization. Moreover, there is a corresponding change of glass transition temperature leading to a variation of supercooled liquid region with increasing x from 48 to 53. The change of T_g and the corresponding crystallization behaviour in (Ti_(33)Zr_(33)Hf_(33))_(100-x)(Ni_(50)Cu_(50))_x alloys with x=48 to 55 show a correlation suggesting that the crystallization behaviour can be taken into account in order to determine the glass-forming ability of the multicomponent alloys, developed by equiatomic substitution.