The investigation of eutectic nucleation and growth mechanism of Al-Si alloy

Abstract

Al-Si binary eutectic transformation, solidification occurred in the late eutectic (cell) crystal nucleation, eutectic nucleation and growth are a direct impact on formation of the defects of organizations (such as: shrinkage, thermal cracking, etc.) and the distribution of impurities elements and compounds, and so on .In this paper, analysis the microstructure of the alloy with modification by Sr, also thermal analysis was used to measure the unmodified alloys, EBSD was used to analysis the alloy with different status. The results showed that: The EBSD technique, whether or not modification, we observed that the eutectic nucleation on the primary dendrite and heterogeneity in inter-dendrites exist, and Sr has a significant effect on the primary α-Al, the primary α-Al phase in the AlSi10.5 alloy modified by 0.04% Al-10 wt. % Sr is more rounded and the size is much smaller than unmodified alloy. Fe has a great influence on the nucleation of eutectic Si.