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以多晶体位错滑移及塑性流动机制为基础,探究了TA15钛合金在高温变形过程中介观层次上形变不均匀性和力学响应。基于率相关晶体塑性理论,建立了描述体心立方结构金属力学行为的本构模型,同时考虑了主滑移系和次滑移系的运动;确定了合理的材料本构参数,高温压缩实验与模拟得到的真应力-应变曲线基本一致。通过对TA15钛合金高温变形模拟结果进行分析,包括应力和应变分布、滑移系开动情况和晶界面积变化,得出:(1)由于晶粒几何及取向的随机性造成应力和应变分布非均匀性;(2)晶粒间相互作用的复杂性会导致各个滑移系开动的差异性;(3)形变程度越大,晶粒密度越大,晶界面积变化率越大。模拟结果为相变等显微组织演变及多尺度同步耦合提供了参考。
Based on the polycrystalline dislocation slip and plastic flow mechanism, the inhomogeneity and mechanical response of the TA15 titanium alloy at mesoscopic level during high temperature deformation were investigated. Based on the rate-dependent crystal plasticity theory, a constitutive model describing the metal-mechanical behavior of the body-centered cubic structure was established, taking into account the motion of the main slip system and the subsliding system. The reasonable material constitutive parameters, high temperature compression experiment The simulated true stress-strain curves are basically the same. The simulation results of high temperature deformation of TA15 titanium alloy are analyzed, including the distribution of stress and strain, the onset of slip system and the change of the grain boundary area. The results are as follows: (1) Because of the randomness of grain geometry and orientation, the stress and strain distribution Uniformity; (2) the complexity of the interaction between the grains will lead to the different slip system start; (3) the greater the degree of deformation, the greater the grain density, the greater the rate of change of the grain boundary area. The simulation results provide a reference for the microstructure evolution and multi-scale synchronization coupling of phase transformation.