Characterisation of phases and lattice parameter measurement in the Al-rich corner of the Al-Si-Ti system

Phases present in Al-12 wt%Si and Al-17.5 wt%Si alloys, with Ti content up to 4 wt%, prepared by rapid cooling, were characterised. The alloys were investigated by optical microscopy, X-ray fluorescence, X-ray diffractometry, scanning electron microscopy and energy dispersive X-ray spectroscopy. The addition of Ti to Al-12 wt%Si alloy led to the precipitation of the intermetallic compound Al₃Ti which dissolves up to 11.59 wt%Si, while its addition to Al-17.5 wt%Si alloy led to the precipitation of the ternary compound AlSi₂Ti. Lattice parameters of the Al-rich phase and Si-rich phase were measured from X-ray diffraction data.