中文摘要：

在自行研制的杆杆型高温冲击拉伸实验装置上对多晶纯钛在不同温度（298～973K）、高应变率（300和1400／s）下的拉伸力学行为进行研究，并通过与准静态下（0．001和0．01／s）的实验结果相比较，揭示纯钛中孪晶变形在拉伸载荷下与温度和应变率的相关性。结果表明，孪晶变形与温度和应变率有着明显的相关性，其密度随着应变率的增加而增大，随着温度的升高而锐减。基于上述实验结果，考虑位错运动和孪晶变形对纯钛塑性变形的影响，建立纯钛温度和应变率相关的宏观本构模型。数据拟合结果表明，该本构模型能够很好地描述纯钛的温度和应变率相关的拉伸力学行为。

英文摘要：

The influences of temperature and strain rate on the deformation twinning of polycrystalline titanium were studied by tensile experiments in a temperature range of 298-973 K and a strain rate range of 0.001-1 400/s. The tests at elevated temperatures and high strain rates were carried out using a modified split Hopkinson tension bar apparatus. The experimental results show that deformation twinning is dependent on both temperature and strain rate. The density of deformation twinning increases with increasing test strain rate. However, it decreases with increasing test temperature. A constitutive model based on the dislocation kinetics and twinning effect was used to describe the stress-strain relationship of commercially pure titanium （CP-Ti） at the investigated temperatures and strain rates. The simulated results show that the model can well describe the stress-strain relationship of CP-Ti in tensile deformation.