钛合金中氢化物应力的再取向

The stress-induced reorientation of hydrides in titanium alloy

在拉应力为50～200 MPa和150～400℃温度循环条件下,研究了应力和温度循环次数对T225合金中氢化物再取向程度的影响．结果表明,随着应力的增大和温度循环次数的增加,T225合金中氢化物再取向的程度提高．氢化物发生再取向时的应力存在一个阈值,当应力低于这个阈值时,即使增加温度循环次数,氢化物再取向也不明显；当应力大于应力阈值时,氢化物应力再取向的程度与应力和温度循环次数的关系式为：R_σ=0．735exp[0．0167N^(0．224)(σ-σ_(th)~N)]．应力阈值随着温度循环次数的增加而降低,它们之间的关系为σ_(th)~N=101+60exp(-0．2N)．

Under the conditions of the tensile stress from 50 to 200 MPa and temperature cycling between 150 ℃ to 400 ℃, the effects of stress and the number of temperature cycling on the hydride reorientation in T225 alloy have been investigated. The results also show that with the increase of stress or the number of temperature cycling, the level of hydride reorientation increases. There is a threshold stress as the hydride reorientation takes place. Below the threshold stress the hydride reorientation is not obvious, even at more number of temperature cycling. When the applied stress is higher than the threshold stress, there are the certain relationships between the level of hydride reorientation with the stress and the number of temperature cycling. The threshold stress is decreased with the increase of the number of temperature cycling.