The effect of temperature and cyclic loading on stress relaxation (SR) behavior of Ti–6Al–4V titanium alloy was studied by uniaxial tensile test. SR limit and rate vary with increasing the temperature and cyclic loading times. The microstructural variations were observed by scanning and transmission electron microscopes. Unstable SR behavior happens at 450–550 °C, which becomes obvious with the increase of cyclic loading times or the decrease of relaxation temperature. The stress instability maybe attributes to the activation energy improvement. Based on dislocation distribution and morphology as well as stress exponent values varying from 1.8 to 2.4, SR mechanism of the alloy is dislocation creep in the tested temperature range. The mechanical properties of the alloy at room temperature almost maintains invariable after SR process. However, the discontinuous yielding in as-received alloy changes to continuous yielding in relaxed ones.

通过单轴拉伸试验研究了温度和循环载荷对 Ti-6Al-4V 钛合金应力松弛 (SR) 行为的影响。SR 限制和速率随着温度和循环加载时间的增加而变化。通过扫描和透射电子显微镜观察微观结构变化。不稳定的 SR 行为发生在 450-550 °C，随着循环加载次数的增加或松弛温度的降低，这种行为变得明显。应力不稳定性可能归因于活化能的提高。基于位错分布和形貌以及应力指数值从 1.8 到 2.4，合金的 SR 机制是在测试温度范围内的位错蠕变。合金在室温下的机械性能在经过 SR 处理后几乎保持不变。然而，