Tensile tests were performed on single crystals of binary and ternary copper alloys with uniform initial orientation and with admixtures of gallium or germanium. A stacking fault energy of 50mJ/m2 was obtained for copper. Stacking fault energies of 87 and 80mJ/m2 were obtained for e/a = 1.03 and 1.06, respectively.

Quergleitspannung und Stapelfehlerenergie von Kupferreichen Mischkristallen.  E.Peissker: Acta Metallurgica, 1965, 13[4], 419-31