Experimental investigation of phase equilibria in the Al–Ag–Si system

The phase equilibria of the Al-Ag-Si ternary system at 500 °C and 600 °C were investigated by X-ray powder diffraction (XRD) and electron probe microanalysis (EPMA). Three two-phase regions ((Al) + (Si), (Si) + Ag2Al, and (Si) + (Ag)) and two three-phase regions ((Si) + (Ag) + Ag2Al and (Si) + (Ag) + Ag2Al) were observed at 500 °C. The (Si) + Ag2Al and (Si) + (Ag) two-phase regions and (Si) + Ag2Al + liquid and (Si) + (Ag) + Ag2Al three-phase regions were identified in the isothermal section at 600 °C. A vertical section of the Al–Ag–Si system along Al0.6Si0.4–Al0.8Ag0.2 was investigated using differential scanning calorimetry (DSC) from which the temperatures of the phase-transition reactions were determined. The isothermal and vertical sections obtained in this study provide fundamental data for the thermodynamics of the Al–Ag–Si system and knowledge of the thermodynamics associated with aluminium-based alloys.