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基于晶体塑性理论,建立了滑移和孪生机制耦合的孪生诱导塑性(TWIP)钢单晶晶体塑性本构模型,通过引入孪晶体积分数及其饱和值,分别考虑了孪生对硬化及滑移的影响,对该本构模型进行数值实现.并通过ABAQUS/UMAT平台上的二次开发,将其应用于TWIP钢单晶典型取向单向加载条件下的力学行为模拟.分析了单晶不同取向下塑性变形的微观机理和滑移系、孪生系的启动状态及其对宏观塑性的影响,尤其是模拟得到黄Cu取向和S取向加载过程的应力突变,再现了Cu单晶实验中的应力陡降现象.结果表明,孪晶体积分数较小时,对应变硬化影响较小;随着孪晶体积分数的增加,对应变硬化的影响逐渐明显;当孪晶体积达到一定量时,孪晶体积达到饱和,孪生增量为0,晶体滑移转向,新的滑移系启动,应力突降.
Based on the crystal plasticity theory, a plastic constitutive model of twin induced plasticity (TWIP) steel single crystal coupled with slippage and twinning mechanism was established. By introducing the twin crystal volume fraction and its saturation value, the twin hardening and slipping , The numerical simulation of the constitutive model was carried out and the mechanical behavior of the TWIP steel under the uniaxial loading of typical single crystal orientation was simulated by the secondary development on the ABAQUS / UMAT platform. The microscopic mechanism of plastic deformation and the start-up state of the slip system and twinning system and its influence on the macroscopic plasticity, especially the stress abrupt changes in the yellow Cu orientation and the S orientation loading process, and the stress drop in the Cu single crystal experiment The results show that the smaller the volume fraction of twinning is, the smaller the strain hardening effect is, the more the twinning volume fraction increases, the more obvious the effect on strain hardening. When the twin volume reaches a certain amount, the volume of twin becomes saturated , Twin increments of 0, crystal slip steering, a new slip system started, and a sudden drop in stress.