中文摘要：

在应变速率为0.001～1270s-1、温度为298～1023K条件下对魏氏组织和双态组织的TC21钛合金进行拉伸试验,利用SEM对拉伸试样的断口进行观察。结果表明：TC21钛合金的拉伸力学行为存在显著的温度和应变速率相关性;当应变速率为0.001和0.05s-1的屈服应力—温度曲线存在转折点,且转折点温度随应变速率的增大而升高;当温度低于转折点温度时,相同氧含量的TC21钛合金和多晶纯钛的屈服应力具有相似的温度相关性;微观组织影响屈服应力的幅值和拉伸塑性的大小,但不影响屈服应力的温度相关性和应变速率相关性;除魏氏组织在室温0.001s-1时为穿晶和沿晶混合断裂外,其他工况下的魏氏组织和双态组织均为穿晶韧性断裂;TC21钛合金在拉伸变形过程中未出现绝热剪切带和形变孪晶。

英文摘要：

Tensile tests were performed on TC21 titanium alloy with Widmanstatten microstructure（W） and bimodal microstructure（BM） at temperature ranging from 298 to 1 023 K and strain rate ranging from 0.001 to 1270 s-1.The results show that the temperature and strain rate have significant effects on the tensile behavior of TC21.At low strain rates of 0.001 and 0.05 s-1,a discontinuity is found in the yield stress—temperature curve.Below discontinuity temperature,the temperature dependence of the yield stress of TC21 is similar to that of cp-Ti that has the same interstitial solute concentration of oxygen.The microstructure affects the magnitude of yield stress and tensile ductility,but not the strain rate sensitivity and temperature sensitivity of the yield stress.The samples with Widmanstatten microstructure show a mixed manner of transgranular fracture and intergranular fracture at room temperature and strain rate of 0.001 s-1,while under other conditions both microstructures show a manner of transgranular fracture.Neither adiabatic shear band nor deformation twinning is found in the tested samples.