冷轧HCP结构合金(CP-Ti)中变形晶粒的晶体学行为：反应应力模型的实验与模拟

对商业纯钛（CP-Ti）退火后冷轧9%变形的板材，利用电子背散射衍射（EBSD）和扫描电子显微镜（SEM）评估了晶粒中激活的滑移系统和孪生系统。同时，采用反应应力（RS）模型模拟了变形晶粒中滑移系统的激活以及晶粒之间的相互作用，该模型将晶粒塑性变形过程视为外加应力和统计变化的晶间反应应力共同作用的结果。结果表明，反应应力模型适用于评价多晶钛的变形行为。该模型预测了变形后的钛晶粒内发生的滑移，实验数据证实了该模型的正确性。变形晶粒中滑移和孪晶的分布不均匀，与晶粒应变分布不均匀相对应。这种不均匀的晶粒应变也可以由取向不同的相邻晶粒变形而产生。当一个晶粒的塑性变形与其相邻晶粒的塑性变形有显著差异时，就会触发附加的局部滑移，从而降低晶粒间的应变不协调。塑性应变在某些情况下是通过机械孪生来实现的，它与滑移协同以满足晶内和晶间的应变连续性。

Crystallographic Behavior of Deformed Grains in Cold-Rolled HCP Alloy (CP-Ti) Using Experiment and Simulation by Reaction Stress Model

After commercially pure titanium (CP-Ti) annealed sheet was cold-rolled to 9% reduction, electron backscatter diffraction (EBSD) and scanning electron microscopy (SEM) were employed to evaluate activated slip and twin in the samples. Meanwhile, the activation of slip systems in deformed grains and the interaction between grains were simulated by reaction stress (RS) model, in which the plastic deformation process in a grain was regarded as a combined consequence of external stress and statistically varied intergranular reaction stress. The results indicate that the reaction stress model is suitable to estimate the deformation behavior of polycrystalline titanium. The model predicts slip occurring in deformed titanium grains, which is confirmed by experimental data. The distribution of slip and twin in deformed grains is non-uniform, connecting to uneven in-grain strain distribution. This uneven in-grain strain can also be generated by deformation of adjacent grains with different crystal orientations. When the plastic deformation in a grain shows significant difference from that of its neighboring grain, additional local slips are triggered to decrease the strain inconsistency. The plastic strain is realized by mechanical twinning in some cases, which combines with the active slips to satisfy in-grain and intergranular strain consistency.