耦合孪生的TWIP钢单晶体塑性变形行为模拟研究

发布时间：2019-03-17 09:07

【摘要】：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.
[Abstract]:Based on the theory of crystal plasticity, a single crystal plastic constitutive model of twin induced plasticity of (TWIP) steel coupled with slip and twinning mechanism is established. By introducing the twin volume fraction and its saturation value, the effects of twin on hardening and slip are considered, respectively. The numerical realization of the constitutive model is carried out. Through the secondary development on ABAQUS/UMAT platform, it is applied to the mechanical behavior simulation of TWIP steel under unidirectional loading with typical single crystal orientation. The microcosmic mechanism of plastic deformation in single crystal with different orientations, the slip system, the starting state of twin system and their effects on macro plasticity are analyzed. Especially, the stress abrupt changes in the loading process of yellow Cu orientation and S orientation are simulated. The stress drop phenomenon in Cu single crystal experiment is reappeared. The results show that the small volume fraction of twins has little effect on strain hardening, and with the increase of twin volume fraction, the effect of twin volume fraction on strain hardening becomes more and more obvious. When the twin volume reaches a certain amount, the twin volume reaches saturation, the twinning increment is 0, the crystal slip turns, the new slip system starts up, and the stress drops abruptly.
【作者单位】：北京科技大学机械工程学院;
【基金】：国家自然科学基金委员会-中国工程物理研究院联合基金项目U1330121 国家自然科学基金项目51105029 北京市自然科学基金项目3112019资助~~
【分类号】：TG142.1

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