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采用规格为Ф4.0 mm×0.3 mm冷轧TLM(Ti-25Nb-3Zr-3Mo-2Sn,TLM))合金细径薄壁管材,分别在660,720℃进行固溶处理以及对720℃固溶态管材在510℃进行时效处理,利用金相显微镜、XRD、室温拉伸及断口观察分析了固溶、时效对管材组织、力学性能的影响。不同固溶态管材均为等轴组织,随着固溶温度升高,平均晶粒尺寸增大。相变点以上的固溶组织由β相和α’’相组成,相变点以下固溶组织还有少量α相。时效过程中,针状的α相在晶界析出更快,合金相变化过程为β+α’’→β+α’’+α→β+α,时效时间大于3 h时,α相的析出使应力-应变曲线的“双屈服”特征减弱;随着时效时间的延长,抗拉强度、屈服强度及弹性模量升高,而延伸率降低。综合分析表明:720℃+510℃,3 h时效态具有较好的综合力学性能。
The thin-walled tubes of Ф4.0 mm × 0.3 mm cold-rolled TLM (Ti-25Nb-3Zr-3Mo-2Sn, TLM) alloy were respectively used for solution treatment at 660 ℃ and 720 ℃, respectively. Aging treatment was carried out at 510 ℃. The effects of solution treatment and aging on the microstructure and mechanical properties of the pipe were analyzed by metallographic microscope, XRD, room temperature tensile test and fracture observation. Different solid solution pipe are equiaxed, with the solution temperature increases, the average grain size increases. The solid solution microstructure above the transformation point is composed of β phase and α “phase, and a small amount of α phase exists in solid solution structure below the transformation point. During the aging process, the needle-like α phase precipitated more rapidly in the grain boundary and the phase transformation of the alloy was β + α ”→ β + α“ + α → β + α. When the aging time was more than 3 h, The stress-strain curve of the ”double yield" feature weakened; with the aging time, the tensile strength, yield strength and elastic modulus increased, while the elongation decreased. Comprehensive analysis shows that: 720 ℃ +510 ℃, 3 h aging state has better mechanical properties.