动态压缩条件下高纯钛微观组织特征研究

Study of Microstructural Characteristics of High-purity Titanium during Dynamic Compression

摘要:

利用光学显微镜(OM)、背散射电子衍射(EBSD)技术及透射电子显微镜(TEM)对高纯钛低-中应变动态压缩变形的微观组织特征进行了研究。结果表明：随着应变量(ε)的增加,晶粒内部通过孪晶与孪晶,孪晶与位错以及位错与位错之间的交互作用逐步细化原始晶粒；变形初期,形变孪生以{11-22}孪晶为主,当ε达到0.2后,{10-12}孪晶转变为主要形变孪生类型,孪生改变了原始晶粒的取向,进一步促进晶粒内部的位错滑移。高纯钛动态压缩变形经历了由位错滑移到形变孪生,再到位错滑移主导的过程,但位错滑移和孪生始终共同作用协调动态压缩变形。

Abstract:

Microstructural characteristics of high-purity titanium during dynamic compression at low-medium strain were studied by optical microscopy (OM), electrical back-scattered diffraction (EBSD) techniques and transmission electron microscopy (TEM). The results show that the original grains are gradually refined by twin-twin, twin-dislocation and dislocation-dislocation interactions. The predomiant twinning system is {11-22} twinning at the beginning of deformation, {10-12} twinning become to the main twinning modes when strain reached 0.2. The orientations of each twinned grain are altered by twinning that further facilitate dislocation glide in interior grains. Though dislocation slip and twinning always work together to coordinate macroscopic plastic deformation, the deformation process of high-purity titanium during dynamic compression is experienced dislocation slip to deformation twinning and dislocation slip again.