Ab initio simulation of alloying effect on stacking fault energy in fcc Fe

• Published in: Computational materials science 2015-03, Vol.99, p.253-255
• Main Authors: Limmer, K.R., Medvedeva, J.E., Aken, D.C. Van, Medvedeva, N.I.
• Format: Article
• Language: English
• Subjects: Ab initio calculation; Alloying effects; Atomic properties; Austenitic steels; Close packed lattices; Density functional theory (DFT); Hexagonal cells; Iron; Mathematical models; Stacking fault energy; Transformation temperature; Transition metals
• ISSN: 0927-0256; 1879-0801
• DOI: 10.1016/j.commatsci.2014.12.015

•Ab initio investigations of alloying effect on the stacking fault energy.•Systematic calculation of SFE in fcc Fe for all 3d and 4d impurities.•Parabolic dependence of SFE follows difference in valence electrons.•Solution model explains the trends excluding additions with fully occupied d-shells. The effect of 3d and 4d transition metal (TM) additions on the intrinsic stacking fault energy (SFE) in fcc Fe is studied to elucidate the role of alloying in the deformation mechanisms in austenitic steels. The results of ab initio calculations reveal that only Mn reduces the SFE, stabilizing the local hcp structure, whereas all other d-additions are expected to decrease the hcp→fcc transformation temperature and restrain the ε-martensite formation. We predict a parabolic dependence of SFE on the atomic number of d-element across the series, with the largest increase in SFE obtained for the early and late elements in the d-series that follow the difference in the valence electrons between the TM and Fe atoms. To understand the SFE behavior in fcc Fe alloys, the driving forces for the fcc to hcp phase transformations of transition metal X and solid solution Fe–X were considered with an ab initio approach. It is found that the solution model explains the SFE trends for all TM additions except the late TMs with fully occupied d-shells (Cu and Ag).