Progress on phase equilibria of the AlSiZr system at 700 and 900 °C

Phase equilibria of the AlSiZr system were investigated using equilibrated alloys. All alloys were studied by X-ray powder diffraction, scanning electron microscopy and energy dispersive spectroscopy. The ternary phase τ1 was found at 700 and 900 °C, while the τ2 phase was only identified at 900 °C. 12 three-phase regions were experimentally determined in isothermal sections of the AlSiZr system at both 700 and 900 °C. The solubility of Si in the intermediate and solution phases (i.e. Al3Zr, Al2Zr, Al3Zr2, AlZr3, α-Al and (Zr)) at the AlZr side is limited, whereas the solubility of Al in the SiZr intermetallic (except the Si2Zr3 phase) is reverse. In addition, Al in the αSiZr phase at 900 °C decreased to 0.5 at.% from 10.3 at.% at 700 °C.