强化层亚结构对TA2疲劳强度的影响

研究了滚压强化多晶纯钛在疲劳前后的显微组织特征和残余应力的变化。结果发现：疲劳强度的提高主要归于形变组织，同时表面粗糙度的降低也起了良好的作用。滚压试样表层TEM组织中形成高密度位错和单个、分散的变形孪晶，历经10^6以上循环周次后，孪晶－晶界的交互作用是其主要特征。滚压引入的残余压应力和层深均较小，有益贡献也相应降低。

Effect of Substructure in Strengthened Layer on Fatigue Strength of Pure Titanium

For polycrystalline titanium after cold rolled (CR), the microstructures and the compressive residual stress before and after fatigue deformation are investigated by transmission electron microscopy (TEM) and X ray diffraction (XRD) respectively. Experimental results show that the microstructure is a predominant factor in improving fatigue strength of pure titanium, and the decrease of surface roughness resulting from CR also has positive effects. High density dislocations, odd and dispersed deformation twins are formed in CR samples. After more than 10 6 cyclic deformations, twin grain boundary interactions play an important role in CR samples. The compressive residual stress value and depth is rather small, and their contribution decreases correspondingly.