The crystallography of the silicon phase in unmodified Al-Si eutectic alloys has been studied by conventional and high-resolution electron microscopy. Examination of the flake morphology eutectic silicon, at two mutually perpendicular 〈110〉 zone axes, revealed internal twin traces at only one 〈110〉 zone axis, parallel to the flake surface. Internal twins in the silicon phase appear to develop as a result of purely two-dimensional crystal growth on pre-existing silicon nuclei containing a group of parallel twins. The twins grow along coplanar 〈112〉 directions by the twin plane re-entrant edge (TPRE) mechanism. Stacking faults and twins present in the high-resolution images of eutectic silicon are consistent with TPRE growth originating at the silicon nuclei containing parallel twins.
ASJC Scopus subject areas
- Condensed Matter Physics