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基于位错密度及孪晶体积分数的演化,建立了Fe-22Mn-0.6C孪晶诱导塑性(TWIP)钢滑移和孪生的塑性物理本构模型,该模型考虑了孪晶内的滑移对整体塑性变形的贡献及孪晶区和基体区Taylor因子的差异,采用基体滑移、孪晶区孪生和滑移的加权求和描述微区塑性变形.考虑应变速率对热激活应力的影响,进一步建立了应变速率与屈服应力之间的关系.采用Euler法对该模型进行数值计算,将计算结果与实验结果进行对比,其平均相对误差值只有0.84%,相对于不考虑孪晶区滑移的模型和考虑孪晶区滑移但未考虑Taylor因子差异的模型,平均误差分别降低1.1%和2.9%.分析了孪晶与滑移机制的相互作用及对宏观变形的影响,结果表明,孪生速率与滑移速率之间负相关,孪生速率增大滑移速率减小;孪生趋于饱和时,孪生速率降低而滑移速率迅速增加;应变速率增加屈服应力增大,而对应变硬化率无显著影响.
Based on the evolution of dislocation density and twin volume fraction, a plastic-physical constitutive model of Fe-22Mn-0.6C twin-induced plasticity (TWIP) steel slip and twin was established. The model considers twin slip The contribution of overall plastic deformation and the difference of Taylor factor between the twinned zone and the basement zone, the plastic deformation of the micro zone is described by the weighted summation of the base slip and twin zone and slippage. Considering the effect of the strain rate on the thermal activation stress, The relationship between strain rate and yield stress was established.The Euler method was used to calculate the model, and the calculated results were compared with the experimental results, the average relative error was only 0.84%, compared with that without considering the twin zone slip The model and the model considering twin zone slip but without considering the Taylor factor difference reduce the average error by 1.1% and 2.9% respectively.The interaction between twin and slip mechanism and the effect on the macro deformation are analyzed.The results show that the twin rate And the slip rate, the twin rate increases and the slip rate decreases. When the twin tends to be saturated, the twin rate decreases and the slip rate increases rapidly. As the strain rate increases, the yield stress increases, while the strain increases No significant effect.