新型锆钛合金的动态拉伸力学性能与微观断裂机制试验研究

采用直接撞击式Hopkinson拉杆装置对新型锆钛合金材料在动态冲击载荷作用下的力学性能进行了试验研究，得到了典型动态拉伸真应力-真应变曲线。试验结果表明，在室温、应变率为800~4000s-1的情况下，材料的动态强度（包含屈服强度σ_0.2、抗拉强度σ_b）、失稳应变、伸长率以及应变能密度均随应变率的增大而增大。采用扫描电子显微镜（SEM）对试件断口进行分析，研究了合金材料在不同应变率状态下的失效断裂特征。结果发现，随应变率的增大，材料的断裂方式由准解理断裂变为韧性断裂。

Tests ofdynamic tensile properties and microscopic fragment mechanism for a new zirconium-titanium alloy

Dynamic tension tests were conducted by employing the SHTB（split Hopkinson tension bar） to study the dynamic machanical properties of a new zirconium-titanium alloy.The dynamic mechanical properties of the alloy were determined at high strain rates ranging from 800 s-1 to 4000 s-1 at room temperature.The results show that the mechanical behavior of zirconium-titanium alloy depends on the strain rate,the dynamic strengths（including σ0.2and σb）,the unstable strain,the elongation,and the strain energy density all increase with the increase of the strain rates.The SEM fractographic observation shows that there exists a strain rate dependence of the fracture mode for the alloy sample.At room temperature and 800 s-1,the sample is brittle,but its fracture modes changes from a quasi-cleavage one to a ductile one with increased strain rates.