Probing temperature effects on the stacking fault energy of GH3536 superalloy using first-principles theory

In this study, the total stacking fault energy (SFE) of GH3536 superalloy was divided into three fundamental terms (chemical, magnetic and strain terms) for investigating the dependence of temperature via ab initio calculations. The present results imply that the incremental trend of SFE value is responsible for the increasing temperature, which indicates a significant temperature dependence for SFE. These results also account for the occurrence of twinning in GH3536 superalloy during plastic deformation at cryogenic temperature and shed light on the relationship between the SFE and deformation mechanisms. The estimated SFE at ambient temperature gains coincident conclusion with the experimental measurement of SFE obtained by using the line-broadening analysis of X-ray diffraction (XRD) in conjunction with the Rietveld method. The discovery provides an essential understanding of potential governing deformation mechanisms for face-centered-cubic (fcc) alloys with low SFE, paving the way for the development of novel materials with excellent resistance to cryogenic temperature.