TiNbTaZr钛合金冷加工塑性行为研究

Cold Working Plastic Deformation for TiNbTaZr Titanium Alloy

通过力学性能测试,结合光学显微镜、X射线衍射、扫描电镜和透射电子显微镜等表征技术,研究了Ti35Nb2Ta3Zr0.3O合金的冷加工塑性行为及其机理。结果表明:Ti35Nb2Ta3Zr0.3O合金在冷变形过程的不同阶段呈现出低加工硬化或无加工硬化的特点,变形量大于50%之后,晶粒碎化明显、塑性增强。分析表明:约35%Nb的加入降低了合金的层错能,使位错攀移及交滑移受到抑制,孪生机制增强,随冷变形量增大,形成多阶孪生,使晶粒明显碎化;合金的塑性变形是以孪生与位错滑移联合起作用,其独特的塑性行为来自于层错能效应及形变过程中的孪生诱发塑性效应。

The cold working plasticity and its mechanism of Ti35Nb2Ta3Zr0.3O alloy were investigated based on mechanical property test,collaborated with optical microscopy,XRD,SEM and TEM analysis techniques.The results show that low work hardening,even no work hardening,occurs at the initial deformation for Ti35Nb2Ta3Zr0.3O alloy.After deformation ratio exceeded 50％,grain size became refined significantly and plasticity was enhanced.It is concluded that the addition of about 35％ Nb can decrease the stacking fault energy of the alloy,which results in the partially inhibition of sliding and climbing of the dislocations.However,the plastic deformation is improved by twinning.During large deformation,multi order twinning happened.It is the reason that the unique plasticity of Ti35Nb2Ta3Zr0.3O alloy is caused by twining and sliding together due to twinning induced plasticity （TWIP） and the low stacking fault energy.