The (α1 + α2) miscibility gap of the Al–Zn–Cu system at 360 °C

The effect of Cu addition on the (α1 + α2) miscibility gap of the Al–Zn binary system was studied at 360 °C by using the diffusion couple technique. It was experimentally verified that the highest temperature of the (α1 + α2) miscibility gap of the Al–Zn system is significantly increased by the addition of Cu. The miscibility gap of Al–Zn–Cu face-centered cubic solid solution becomes smaller with the addition of Zn than that of the Al–Cu binary system above 351 °C, which is in agreement with previous thermodynamic predictions.