预变形及时效对Ti-50.7at%Ni温控合金回复应力的影响
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摘要
采用热循环处理及室温和高温拉伸试验等方法分别研究了预变形和时效对Ti-50.7at%Ni温控合金显微组织及回复应力的影响。结果表明:适当的预形变处理,会提高合金的回复应力;时效处理会使合金中的沉淀相Ti_3Ni_4弥散析出,Ti_3Ni_4对B2母相的钉扎作用使基体得到强化,400℃时效时析出的沉淀相Ti_3Ni_4最多,合金的回复应力最大,为50MPa,过长的时效时间会破坏B2和B19'的共格关系,组织逐渐恢复,回复应力显著降低。回复应力的大小是由沉淀相Ti_3Ni_4的析出速率和组织的回复进程共同决定的。
The effects of predeformation and aging on the microstructure and recovery stress of Ti-50.7 at%Ni alloy were studied by thermal cycling treatment and tensile test at room and high temperature. The results show that, the recovery stress of the alloy increases by proper predeformation treatment. The precipitation phase Ti_3Ni_4 in the alloy can be precipitated out by aging treatment. The binding effect of Ti_3Ni_4 on the B2 phase makes the matrix strengthened. The content of precipitated phase Ti_3Ni_4 is the most when aged at 400 ℃, and the recovery stress of alloy is maximum, which is 50 MPa. Excessive aging time can destroy the coherent relationship of B2 and B19'. The microstructure gradually recovers and the recovery stress decreases significantly. The recovery stress is determined by the precipitation rate of Ti_3Ni_4 and the recovery process of the microstructure.
The effects of predeformation and aging on the microstructure and recovery stress of Ti-50.7 at%Ni alloy were studied by thermal cycling treatment and tensile test at room and high temperature. The results show that, the recovery stress of the alloy increases by proper predeformation treatment. The precipitation phase Ti_3Ni_4 in the alloy can be precipitated out by aging treatment. The binding effect of Ti_3Ni_4 on the B2 phase makes the matrix strengthened. The content of precipitated phase Ti_3Ni_4 is the most when aged at 400 ℃, and the recovery stress of alloy is maximum, which is 50 MPa. Excessive aging time can destroy the coherent relationship of B2 and B19'. The microstructure gradually recovers and the recovery stress decreases significantly. The recovery stress is determined by the precipitation rate of Ti_3Ni_4 and the recovery process of the microstructure.
引文
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