Thermodynamic calculation of stacking fault energy in Fe–Mn–Si shape memory alloys

Based on thermodynamic considerations together with measurement of the stacking fault probability (Psf) by X-ray diffraction profile analysis, the stacking fault energy (SFE, γ) of austenite in Fe–Mn–Si shaped memory alloys can be estimated. For instance, the stacking fault energy of an fcc(γ) phase in an Fe–30.3Mn–6.06Si was calculated as 7.8 mJ/m². Compositional dependence of stacking fault energy in these alloys with certain composition range has also been derived as SFE(γ)=180.54+7.923 wt.% Mn–46.38 wt.% Si (J/mol), showing that the stacking fault energy increases with the addition of Mn and decreases with the addition of Si.