The influence of interstitial carbon on the γ-surface in austenite

The intrinsic stacking-fault energy (SFE) is a crucial parameter for understanding the plastic deformation behavior of face-centered cubic materials such as austenitic steels. In order to investigate the influence of interstitial carbon on the SFE of iron, we perform ab initio calculations within the framework of density functional theory. By utilizing the linearized augmented planewave method, we compute the SFE for a variety of carbon concentrations, i.e. Fe, Fe24C and Fe3C, as well as different carbon locations with respect to the stacking-fault plane. Our results demonstrate a strong influence of both parameters on the SFE, in agreement with previous experimental and theoretical reports. Moreover, we compute the generalized SFE (also known as the γ-surface), which provides information about the behavior of the material under shear stress.