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工业纯钛TA2中低温蠕变行为存在显著的温度及应力相关性。基于外加应力水平和蠕变应变的变化关系,确定不同蠕变温度下的门槛应力水平。根据短时蠕变实验数据,利用包含稳态蠕变速率的本构方程外推稳态蠕变速率,而后进行两组相对长时的蠕变实验,证明了工业纯钛中低温蠕变存在稳态蠕变阶段。利用稳态蠕变速率与应力关系,计算出工业纯钛室温蠕变应力指数为6.96,也说明了外推稳态蠕变速率的可靠性。中低温蠕变激活能随着蠕变进行变化不大(≈60 k J/mol),但一直大于以位错为变形主导机制的变形激活能(30~40 k J/mol),表明孪晶对于工业纯钛中低温蠕变发展整个阶段均起重要作用。根据蠕变后试样孪晶结构随温度的变化解释了TA2蠕变行为的温度相关性,同时也证明了孪晶对于TA2蠕变行为的重要性.
Industrial pure titanium TA2 creep behavior at low temperature there is a significant correlation of temperature and stress. Based on the relationship between the applied stress level and the creep strain, the threshold stress level at different creep temperatures is determined. According to the short-term creep experimental data, steady-state creep rate is extrapolated by the constitutive equation including the steady-state creep rate, and then two groups of relatively long-time creep experiments are conducted, which proves that creep at low temperature exists in industrial pure titanium State creep stage. Using the relationship between steady creep rate and stress, the creep stress index of industrial pure titanium at room temperature is calculated to be 6.96, which also shows the reliability of the extrapolated steady creep rate. The creep activation energy at middle and low temperatures did not change much with creep (≈60 kJ / mol), but it was always larger than the deformation activation energy (30-40 kJ / mol) dominated by dislocations, indicating that the twin It plays an important role in the whole stage of low temperature creep development in industrial pure titanium. The temperature dependence of the creep behavior of TA2 is explained by the change of twin structure with creep temperature, and the importance of twinning for TA2 creep behavior is also demonstrated.