Comparative Study on Relationship Between Modification of Si Phase and Thermal Conductivity of Al–7Si Alloy Modified by Sr/RE/B/Sb Elements

Abstract

Great attention has been focused on the design of good thermal conductivity and high-strength Al–Si alloys to ensure the dissipation of heat and load of electronic components. In this study, the Al–7Si alloy was modified by various content additions of Sr, B, RE and Sb elements. The results show that these modifiers can significantly improve the thermal conductivity and electrical conductivity of Al–7Si alloys to varying degrees. Among them, the 0.05 wt% Sr-modified Al–7Si alloy achieves the highest thermal conductivity (169.6 W/m K) and electrical conductivity (24.27 MS/m). The higher conductivity is due to the systematic optimization of eutectic Si. Sr-modified Al–7Si alloy can change the size, distribution of the eutectic Si phase and transform them from coarse plate-shaped to a fine short slab-shaped or coral-shaped. By these means, it will increase the number and mean free paths of heat transfer electrons, thereby improving the thermal conductivity of Al–7Si alloy.