纯钛滚压形变强化的研究

Investigation of deformation strengthening of cold-rolled pure titanium

采用TEM,XRD技术研究了多晶纯钛滚压形变强化疲劳前后的显微组织特征和残余应力.实验结果发现:多晶纯钛疲劳抗力的提高主要是由于形变显微组织和残余压应力的产生及表面粗糙度的降低.滚压组织中形成高密度位错和单个?分散的变形孪晶,历经106以上的循环周次后,孪晶-晶界的交互作用是其主要特征.疲劳后次表面残余压应力松弛较表面严重.

For polycrystalline titanium after cold-rolling (CR), the microstructure and the compressive residual stress before and after fatigue deformation have been respectively studied by transmission electron microscopy (TEM) and X-ray diffraction (XRD). The experimental results show that the microstructure and the compressive residual stress are predominant factors in improving fatigue resistance of Ti alloy, and the surface roughness resulting from CR has positive effects. High density of dislocations, odd and dispersed deformation twins are formed in the CR. After more than 106 cyclic deformations, twin-grain boundary interactions play an important role in the CR. Residual stress has relaxed more severely in the subsurface than in the surface after fatigue deformation.