中文摘要：

研究Si元素的添加对Ti-55Ta合金的微观组织、力学性能及形状记忆特性的影响。结果表明：合金的微观组织主要由α＇＇马氏体相和少量β相组成;当添加Si时,合金晶粒明显细化,且当x=0.2时,合金中开始析出沉淀相,这些沉淀相主要集中在晶界处,可以阻碍晶粒长大,从而进一步细化合金晶粒。背散射电子衍射分析表明,该沉淀相为（Ti,Ta）3Si相。Ti-55Ta-xSi合金的拉伸应力—应变曲线呈现明显的双屈服现象,且随着Si含量的增加,合金的拉伸和屈服强度升高,伸长率反而减小。Si的添加可以明显改善Ti-55Ta合金的形状记忆效应,且在x=0.1时,合金呈现出最大的形状记忆效应及最低的弹性模量。

英文摘要：

The effects of Si addition on microstructures, mechanical and shape memory properties of Ti-55Ta biomedical alloy were investigated. The results show that the microstructures consist of mainly α′′ martensite and a little β phase, and the grain size decreases obviously with increasing Si addition. When x = 0.2, small （Ti, Ta）3Si precipitates are formed at grain boundaries. With further increasing Si content, the amount of the precipitates gradually increases. The tensile and yield strength of Ti-55Ta-xSi alloys gradually increase with increasing Si addition, whereas elongation decreases. Ti-55Ta-0.1Si alloy exhibits the lowest elastic modulus and the best shape memory recoverable strain. It is revealed that the refinement of grain and the precipitation of （Ti, Ta）3Si phase are responsible to the changes of their mechanical and shape memory properties.