TA2拉压力学性能不对称性及应变速率敏感性

Asymmetry of Tension-Compression Performances and Strain Rate Sensitivity of TA2

研究了不同应变速率下工业纯钛TA2室温拉伸和压缩力学行为。结果发现,TA2具有明显的拉压屈服不对称性和拉压应变硬化不对称性;随着应变速率的增加,拉压不对称性有明显增加。采用电子背散射衍射(EBSD)技术分析了拉伸和压缩时TA2微观变形机制及微观组织演化规律。结果表明,TA2压缩时以孪晶变形机制为主,拉伸时以位错滑移为主;TA2微观变形行为的载荷敏感性导致了宏观力学性能的不对称性。

The behavior of commercially pure titanium(TA2)under tension and compression was investigated at different strain rates.Significant tension-compression asymmetry in yielding and strain hardening were observed.The results show that with the increase of deformation strain rate,the asymmetry of TA2 increases.The microscopic deformation mechanisms and microstructure evolutions of commercially pure titanium under tension and compression were analyzed by electron backscattered diffraction(EBSD)techniques.The results show that the compressive deformation of commercially pure titanium is dominated by deformation twinning while the tensile deformation is dominated by the dislocations sliding.The macroscopic tension-compression asymmetry of commercially pure titanium is determined by load sensitivity of microscopic deformation behaviors and its strain rate sensitivity is due to the different influences of strain rate on properties of tension and compression.