Electron microscope study of stacking fault energies in Cu-11.5 and 16.0 At. Pct Al alloys at temperatures between 20 and 700°C

The temperature dependence of stacking fault energies in Cu-11.5 and 16.0 at. pct Al alloys was determined by means of the extended node technique using a hot-stage in a 500 kV electron microscope. The temperature range was from 20 to 700°C. The stacking fault energy increased markedly with increasing temperature above ~200°C in both alloys (13.6 erg/cm2 and 16.2 erg/cm2 at 20°C and 500°C in Cu-11.5 at. pct Al alloy and 11,7 erg/cm2 and 16.9 erg/cm2 at 20°C and 700°C in Cu-16.0 at. pct Al alloy, respectively). The increasing rate of the stacking fault energies was 0.9 ~ 1.0 erg/cm2/100°C at temperatures above ~200°C in both alloys.