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

The phase equilibria of the Al-Ag-Si ternary system at 500 degrees C and 600 degrees 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 degrees 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 degrees 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 tem-peratures 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 ther-modynamics associated with aluminium-based alloys.