First-principles prediction of the deformation modes in austenitic Fe-Cr-Ni alloys

• Published in: Applied physics letters Vol. 108; no. 8
• Main Authors: Li, Wei, Lu, Song, Kim, Dongyoo, Kokko, Kalevi, Hertzman, Staffan, Kwon, Se Kyun, Vitos, Levente
• Format: Journal Article
• Language: English
• Published: Melville American Institute of Physics 22-02-2016
• Subjects: Applied physics; Chemical composition; Chromium base alloys; Chromium nickel alloys; Deformation; Deformation effects; Deformation mechanisms; Ferrous alloys; First principles; High temperature; Iron; Organic chemistry; Predictions; Slip; Stacking fault energy; Twinning
• ISSN: 0003-6951; 1077-3118; 1077-3118
• DOI: 10.1063/1.4942809

First-principles alloy theory is used to establish the γ-surface of Fe-Cr-Ni alloys as function of chemical composition and temperature. The theoretical stacking fault energy (SFE) versus chemistry and temperature trends agree well with experiments. Combining our results with the recent plasticity theory based on the γ-surface, the stacking fault formation is predicted to be the leading deformation mechanism for alloys with effective stacking fault energy below ∼18 mJ m−2. Alloys with SFE above this critical value show both twinning and full slip at room temperature. Interestingly, twinning remains a possible deformation mode in addition to full slip even at elevated temperatures, in line with observations.