中文摘要：

研究固溶和双重时效Ti2.5Cu合金在室温和77K下的疲劳性能及微观变形机制。结果表明,Ti2.5Cu合金在293和77K下的疲劳塑性指数分别为–0.68和–0.5。室温疲劳变形机制以位错滑移为主;低温疲劳变形中,孪生切变相当活跃,形成多种类型的孪晶。同时针状Ti2Cu强化相阻碍了位错的运动从而形成明显的循环硬化,但对孪晶的形成没有明显的阻碍作用。

英文摘要：

Fatigue properties and deformation mechanism of Ti2.5Cu alloy were studied after solution and two-step aging at 293 K and 77 K. The results show that the fatigue plastic index of Ti2.5Cu alloy at 293 K and 77 K were –0.68 and –0.5,respectively. At 293 K dislocation slip mechanism was dominant. However,at 77 K twinning shear was rather active and various types of twins were found. Meanwhile,needle-like Ti2Cu strengthening phases hindered movement of dislocation and brought about obvious cyclic hardening,but they had little effect on the twinning process.