中文摘要：

利用分离式霍普金森压杆对扁平帽型试样进行加载，结合高速红外测温技术与“冻结”试样的金相微观观察，分析了TA2钛合金受迫剪切过程的力学响应及绝热剪切温度演化特性，探讨绝热剪切失稳起始温度及条件．实验结果显示：绝热剪切带起始时刻温度约为470K，明显低于再结晶温度．在此温度下，热软化还不足以导致材料应力应变曲线软化，因此，热软化可能不是绝热剪切带起始的控制因素，相反一旦绝热剪切带形成，带内应变高度局域化导致温度发生陡然上升．若以此温度作为绝热剪切起始条件，则随平均变形速度增大，试样绝热剪切起始及破坏位移减小．

英文摘要：

In this paper, the adiabatic shearing of TA2 Titanium alloy is investigated in flat-hat-shaped specimens loaded by Split Hopkinson Pressure Bar. The shear stress-displacement curves and temperature evolution in the shear deformation zone are measured experimentally. Deformation localization and adiabatic shear band （ASB） of ＂freezing＂ samples are analyzed by means of metallography. The experimental results show that ASB is initiated at about 470 K, which is evidently lower than the recrystallization temperature （about 930 K）. This temperature rise does not cause descending of flow stress, which means that thermal softening may not be the key condition for ASB initiation. On the contrary, once ASB is initiated, the high localized strain would lead to a sharp rise of temperature. Furthermore, the shear displacement of specimen for ASB initiation and rupture shows a decreasing trend with increasing loading rate.