The stacking fault energy was measured as a function of temperature between 20 and 710C in hexagonal and cubic Co, hexagonal 85% Co 15% Ni and cubic 67% Co 33% Ni. The so-called node method was used for the calculation of the stacking fault energy. It was found that the stacking fault energy decreased with increasing temperature in the hexagonal materials and increased in the cubic materials and that the stacking fault energy was not zero at the temperature of the hexagonal close-packed to face-centered cubic transformation but was between 10 and 20mJ/m2 in both the cubic and the hexagonal phases.

The Temperature and Concentration Dependence of the Stacking Fault Energy in the Co-Ni System. T.Ericsson: Acta Metallurgica, 1966, 14[7], 853-65