摘要
In order to overcome the embrittlement of metastable titanium alloys caused by the precipitation ofωiso phase during aging,regulation of isothermalωprecipitation was investigated in Ti−15Mo alloy.The results show that the sample is brittle when direct aging(A)is applied at 350℃for 1 h after solution treatment(ST).If pre-deformation(D)is performed on the ST sample to induce{332}twins and secondaryα″phase,subsequent aging at 350℃(STDA350)improves the strength to 931 MPa with a good ductility of about 20%maintained.However,when aging is performed at 400℃or 450℃(STDA400/450),the strength can be further improved,but the ductility is dramatically reduced.Atomic-scale characterizations show that the partial collapse ofωphase in the STDA350 sample effectively eliminates aging-induced embrittlement,but complete collapse leads to poor ductility in the STDA400/450 sample.
为了克服亚稳钛合金时效过程中ωiso相析出引起的脆化,研究了Ti-15Mo合金等温ω相的析出规律。结果表明,固溶处理试样在350℃直接时效1 h后表现出脆性断裂特征。对固溶试样进行预变形以诱导{332}孪晶和次生α″相形成,并随后在350℃下时效(STDA350)可将强度提高到931 MPa,并保持约20%的良好延展性。预变形试样在400℃或450℃进行时效时(STDA400/450),强度可以进一步提高,但延展性会显著降低。原子尺度表征表明,STDA350试样中ω相结构部分坍塌,有效消除了时效引起的脆化;但STDA400/450试样中ω相结构完全坍塌,导致延展性较差。
基金
the financial support from the National Natural Science Foundation of China (No. 52374380)
the China Postdoctoral Science Foundation (Nos. 2023M730234, 2024T171126)。
