Modelling of Mechanical Response and Microstructure Evolution of EA4T Steel during Hot Compression Using the Improved Crystal Plasticity Finite Element Method

In order to study the plastic deformation behavior of EA4T steel at high temperature, an improved Asaro hardening modulus was proposed and introduced into the crystal plasticity finite element (CPFEM) together with the dislocation density evolution equation to predict the true stress-strain curve and average grain size obtained from the experiment. The improved CPEFM is evaluated by the statistical results of correlation coefficient, root mean square error and relative error. Then the finite element simulation of the compression process is carried out by using the sub-model method in abaqus to observe the true stress, strain and dislocation density changes in each region of the sample during the compression deformation process. The hot compression experiments were carried out on Gleeble-3800 thermal simulator with strain rate of 0.01 similar to 1/s, temperature of 1243 similar to 1443 K, true strain of 0.2 and 0.8 to obtain true stress-strain and microstructure experimental data. The experimental results show that the mean values of the correlation coefficient, root mean square error and relative error of the statistical results of the improved crystal plasticity finite element model are 0.9989, 1.8732 and 0.0948%, respectively, indicating that it can better describe the true stress-strain curve obtained in the experiment. Combined with the sub-model method, it can better predict the average grain size of the region of interest. At the same time, the numerical changes of the microscopic simulation of the region of interest in the compression process of the specimen can be observed more intuitively, and the thermal compression process can be further understood.