Thermodynamic calculation of stacking fault energy of the Fe-Mn-Si-C high manganese steels

To determine right thermodynamic parameters in calculating the stacking fault energy (SFE) in Fe-Mn-Si-C high manganese steels, deformation mechanisms of several Fe-Mn-Si-C high manganese steels were studied, and their SFEs were calculated through thermodynamic model using two sets of parameters, respectively. The results showed that the parameters of Scientific Group Thermodata Europe (SGTE) could be used to calculate the SFE and predict the deformation mechanisms of Fe-Mn-Si-C steels properly. The addition of Si significantly lowered their SFE rise due to the increase of Mn content. The increase of C content strongly raised their SFE but lowered their SFE rise due to the increase of Mn content. When the Mn content is lower, their SFE first increased with raising Si content up to a critical value, over which they decreased with Si content. This critical value of Si dropped with the rise in Mn and C contents. The increase of Mn content had little effect on the SFE of the Fe-xMn-6Si-1C steels.