Modeling of Stacking Fault Energy of High Manganese Stainless Steel

High manganese stainless steel deformation behavior depends mainly on the stacking fault energy (SFE). There are various deformation mechanisms such as Transformation Induced Plasticity (TRIP) where SFE <18 mJ/m2, Twinning Induced Plasticity (TWIP) if the SFE is in the range of 18–35 mJ/m2, and the slipping process will be the dominating mechanism in case that SFE is higher than 35 mJ/m2. In this work, stacking fault energy of Fe-0.22C-19Mn-14Cr-2Al was calculated to study the effect of grain size as well as the effect of alloying elements (C, Mn, Cr, Al, Si) using two routes; the first is a simulation software JMatPro 13.1, and the second is a thermodynamically based model which was programmed with Wolfram Mathematica software. Based on the two routes, increasing Al and Mn content increased SFE. On one hand, increasing Si content increased SFE based on JMatPro calculations, On the other hand, it was found to decrease the SFE on the other route. For C, the two routes agreed that increasing carbon content led to an increase in SFE of 0.5%. Adding Cr element resulted in a linear increase in SFE for the thermodynamically based model, unlike JMatPro, which showed an increase of up to 9% and then a slight decrease.