中文摘要：

本文对Ti-3.5Al-5Mo-6V-3Cr-2Sn-0.5Fe高强β钛合金采用先低温（350℃）时效以析出ω相,再经高温（450℃~550℃）时效析出次生α相组织,对比组仅采用高温的单级时效,研究分析不同的时效工艺对高强β钛合金显微组织及力学性能的影响规律。结果表明：采用先低温时效,后高温时效的双级时效时,合金在350℃时效2h时后析出ω相,再经高温时效时ω相转化为次生α相。与单级时效相比,低温时效形成的ω相通过辅助形核作用可获得更加细小的次生α相组织,同时其力学性能得到较大提高,但是塑性有所下降。

英文摘要：

In this paper, studied the Ti-3. 5Al-SMo-6V- 3Cr-2Sn-0. 5Fe high strength β titanium alloy with the low temperature （350 ℃）,to precipitate ω phase,and then aged at the high-temperature （450℃- 550℃） to precipitate α phase. The effect of low-temperature aging on microstructure and mechanical properties of high strength β titanium alloy has been investgated. Results shown that the alloy after duplex aging treatment the isothermal co phase precipitated at 350℃/2h,and the transformed to the a phase at the high-temperature. Compared to the single aging heat treatment, co-assisted nucleation can refine the secondary α phase and improve the mechnical properties of the alloy, but the plascity decreased somehow.