Using thermodynamic considerations, together with measurements of the stacking-fault probability via X-ray diffraction profile analysis, the stacking-fault energy of austenite in Fe–Mn–Si shape-memory alloys could be estimated. The stacking-fault energy of a fcc phase in an Fe–30.3Mn–6.06Si alloy was calculated to be 7.8mJ/m2. The compositional dependence of the stacking-fault energy in these alloys was also derived:

stacking-fault energy (J/mol) = 180.54 + 7.923wt%Mn–46.38wt%Si

showing that the stacking-fault energy increased with the addition of Mn and decreased with the addition of Si.

Thermodynamic Calculation of Stacking Fault Energy in Fe–Mn–Si Shape Memory Alloys. X.Jin, J.Zhang, T.Y.Hsu: Materials and Design, 2000, 21[6], 537-9