Fe-11Mn-4Al-0.2C中锰钢动态变形行为及其本构模型

基于准静态和动态拉伸实验，建立Fe-11Mn-4Al-0.2C中锰钢在2×10^-3~200s^-1应变速率下变形行为的Johnson-Cook(J-C)本构模型.结果表明，应变速率对弹性变形阶段无影响.在塑性变形初期，实验钢强度随应变速率增加而增加，在塑性变形中后期，实验钢强度随应变速率增加而减少.实验钢应变速率敏感性(SRS)指数m随着应变的增加，由0.013逐渐转变为-0.018.基于实验数据建立J-C本构模型，拟合效果不佳，存在5.1%的相对误差;通过改变应变速率强化系数，提出修正J-C模型，模型具有更好的拟合效果，表现出更小的相对误差，约为1.6%.

Dynamic Deformation Behavior and Its Constitutive Model of Fe-11Mn-4Al-0.2C Medium-Mn Steel

Based on quasi-static and dynamic tensile tests， deformation behaviors of Fe-11Mn-4Al-0.2C medium manganese steel at strain rates of 2×10^-3~200s^-1 were studied， and the corresponding Johnson-Cook(J-C)constitutive model was established. The results show that the strain rate has no effect on the stage of elastic deformation. In the early stage of plastic deformation， the strength of the tested steel increases with increase of the strain rate， while it decreases in the latter stage of plastic deformation. The strain rate sensitivity(SRS)index m of the tested steel changes from 0.013 to-0.018 with increases of the applied strain. The original J-C constitutive model did not fit well with the experimental data and was a relative error of 5.1%. After modifying the enhancement coefficient of strain rate， the revised J-C model is proposed with a better fitting and smaller relative error about 1.6%.