Morphological features of unmodified eutectic Si and morphological transformation after solution treatment

Abstract

The morphological features of unmodified eutectic Si microstructure before and after solution treatment were revealed by the deep etching technique with a hypoeutectic Al-Si casting alloy as the study material. Before the solution treatment, the unmodified eutectic Si particles showed multi-faceted morphological features such as sheet-like, parallel hexahedral, truncated pyramidal, triangular platelet-like, octahedral, etc. After the six-hour solution treatment, the eutectic Si particles exhibit non-faceted morphological features such as spheroidal, cylindrical, and edge rounding. In addition, the edge rounding transformation of the octahedral Si particle during the holding process of solution treatment is visualised in combination with the molecular dynamics simulation.