Sb对Au-Ge共晶合金铸态组织的影响

Influence of Sb on As-cast Microstructure of Au-Ge Eutectic Alloy

利用光学显微镜和电子探针表征了Au-Ge共晶合金的显微组织,通过DSC测试了其熔化曲线和凝固曲线,研究了添加0.2%的Sb对Au-Ge共晶合金铸态组织的影响。结果表明,添加0.2%的Sb后,Au-Ge共晶合金的初生α-Au相由针状或长杆状变为树枝状或花瓣状,其尺寸明显变小。同时,共晶组织中颗粒状的共晶Ge相的尺寸减小。初生α-Au相及共晶Ge相的细化机理分别归结为元素Sb引起的成分过冷及共晶过冷度增大。

The microstructure of Au-Ge eutectic alloy was characterized using optical microscope and electron probe micro-analyser,and its melting and solidification curves were tested by DSC in order to understand effects of 0.2% Sb addition on as-cast microstructure of Au-Ge eutectic alloy.The results show that primaryα-Au phase morphologies in Au-Ge eutectic alloy are converted from long rod/needle into petal/dendrite with 0.2% Sb addition,and its size is refined significantly.Meanwhile,the size of granular eutectic Ge phase is reduced remarkably.The refinement mechanism of primaryα-Au phase and Ge phase is attributed to constitutional supercooling and eutectic undercooling degree increase caused by the element Sb,respectively.