The stacking-fault energy was measured as a function of temperature between 20 and 710C in hexagonal and cubic Co, hexagonal Co-15%Ni and cubic 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