Phase diagram of Au–Al–Pd at 500 °C

Abstract

The isothermal phase diagram of Au–Al–Pd at 500?°C was constructed using diffusion couples and equilibrated bulk alloys. Electron microprobe analyses were used to determine the phase compositions and phase relationships. Thirteen three-phase equilibria and two ternary phases (T₁ and T₂) were identified in this study. Phase T₁ contained 37?at% Au, 26?at% Pd, and 37?at% Al. Phase T₂ contained 44?at% Au, 24?at% Pd, and 32?at% Al. The Au solubility in the Al₃Pd₂, AlPd, and AlPd₂ phases were 6, 15, and 34?at%, respectively. The Pd solubility in the AuAl₂, Au₂Al, Au₈Al₃, and Au₄Al phases were 5, 10, 13, and 3?at%, respectively.