Morphology and Phase Formation During the Solidification of Al-Cu-Si and Al-Ag-Cu Ternary Eutectic Systems

The analysis was based on theoretical models developed in the literature for solidification of ternary eutectic system alloys under simple lever rule assumptions. Optical microscopy (OM), scanning electron microscopy (SEM) and energy dispersive X-ray microanalysis (EDAX) were used to study the microstructure formed in each case.

The observations were consistent with model predictions: Al-Cu-Si system showed two binary eutectics: non faceted-non faceted (nf-nf) AlCu and faceted-non faceted (f-nf) AlSi, Al-Ag-Cu system showed 2 binary regular eutectics (nf-nf) and a ternary semi-regular Brick type eutectic. The results provided an example of a methodology for use in ternary and multicomponent alloys.