基于应变补偿的Fe-Mn-Al-C低密度钢等温压缩物理本构方程

Physical constitutive equation of Fe-Mn-Al-C low density steel under isothermal compression based on strain compensation

采用Gleeble-1500D热模拟实验机,对Fe-27.51Mn-8.69Al-1.12C低密度钢在变形温度为900~1100℃和应变速率为0.01~5 s^(-1)范围内进行热压缩实验,通过实验数据分析了该钢的流动应力曲线特征,建立了考虑应变耦合的物理本构模型,并进行了验证分析。结果表明:变形温度和应变速率等热力学条件对低密度钢的流动应力影响较为显著,高温、低应变速率更有利于低密度钢的再结晶发生;基于峰值应力的低密度钢等温压缩物理本构方程的预测精度较高,其线性拟合相关系数为0.991;基于应变补偿的低密度钢等温压缩物理本构方程能够较好地描述其在热压缩条件下的流动应力变化规律,其相关系数r为0.980,预测值与实验值的平均相对误差AARE为6.9%。

The thermal compression experiment of Fe-27.51Mn-8.69Al-1.12C low density steel under the temperature of 900-1100℃and the strain rate of 0.01-5 s^(-1) was carried out by thermal simulation experiment machine Gleeble-1500D,and the rheological stress curves characteristics of the steel were analyzed by the experimental data.Then,the physical constitutive model considering strain coupling was established,and the verification analysis was conducted.The results show that the thermodynamic conditions such as deformation temperature and strain rate have significant effects on the rheological stress of low density steel,and the high temperature and low strain rate are more conducive to the recrystallization of low density steel.The prediction accuracy of physical constitutive equation for low density steel under isothermal compression based on peak stress is high,and the linear fitting correlation coefficient is 0.991.The physical constitutive equation of low density steel under isothermal compression based on strain compensation can better describe the change rule of rheological stress for low density steel under hot compression,the correlation coefficient r is 0.980,and the average relative error AARE between the predicted and experimental values is 6.9%.