The stacking fault energy of Cu-2at% Al was estimated to be 83mJ/m2 via the faulted dipole method and by extended node measurements. Using this value, the stacking fault energy of copper was estimated to be 94mJ/m2. It was shown that the variation in stacking fault energy of Cu-Al alloys with concentration was given approximately by γCuexp{-10.2[C/(1+C)]2}, where C = X/X0, X was the alloying concentration (at%) and X0 was the solubility limit (at%) at high temperatures.

Stacking Fault Energies of α-Cu-Al Alloys. C.S.Pande: Physica Status Solidi B, 1970, 37[1], 151–7