TA15钛合金的高温蠕变行为

Creep behaviour of TA15 alloy at elevated temperature

研究TA15钛合金在500~525℃下的高温蠕变行为，实验应力为250～350 MPa。计算合金在不同应力、不同温度下的稳态蠕变速率和应力指数以及蠕变激活能，并通过引入临界应力的概念对稳态蠕变的 Arrhenius 方程式进行修正，得出不同温度下的临界应力以及合金的真实蠕变应力指数，在此基础上研究其蠕变变形机制。研究结果表明，蠕变应力为350 MPa时，合金的蠕变激活能Qapp=403.1 kJ/mol；500℃和600℃下，TA15合金的蠕变临界应力？0值分别为82.15 MPa和34.79 MPa；500℃，TA15合金的真实蠕变应力指数P值为1.7～4.3，600℃时，合金的P值为4.0～6.0；在实验温度和应力范围内，位错的攀移和滑移在TA15合金蠕变变形过程中的作用很大，其中以位错攀移为主，位错滑移为辅。

Creep behavior of a nearαtitanium alloy TA15 at 500~525℃and the stress of 250~300 MPa was investigated. Steady state creep rate, stress exponent n and activation energy Qapp were calculated for the alloy at different temperature and various stresses.The Arrhenius equation was corrected by introducing concept of threshold stress？0, the threshold stress at different temperature and true stress exponent P were calculated; and creep deformation mechanism was also analysed.The results indicate that the activation energy Qapp is 403.1 KJ/mol at stress of 350 MPa. The value of threshold stress？0 at 500 and 600℃are 82.15 MPa and 34.79 MPa. The true stress exponents p varies from 1.7 to 4.3 for the samples tested at 500℃, and 4.0 to 6.0 at 550℃.At the testing temperature range, the rate-controlling mechanism for creep is dislocation climb, subordinating with dislocation sliding, which all play important role in this process.