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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。
The effects of Si addition on microstructure, mechanical properties and shape memory properties of Ti-55Ta alloy were investigated. The results show that the microstructure of the alloy is mainly composed of α ’’ martensite phase and a small amount of β phase. When Si is added, the grain size of the alloy is obviously refined. When x = 0.2, precipitation phase begins to precipitate in the alloy. Phase mainly in the grain boundaries, can hinder the grain growth, thereby further refining the alloy grains. Backscattered electron diffraction analysis shows that the precipitated phase is (Ti, Ta) 3Si phase. The tensile stress-strain curve of Ti-55Ta-xSi alloy shows obvious double-yield phenomenon. With the increase of Si content, the tensile and yield strength of the alloy increases, while the elongation decreases. The addition of Si can obviously improve the shape memory effect of Ti-55Ta alloy, and at x = 0.1, the alloy exhibits the largest shape memory effect and the lowest elastic modulus.