Improving thermal conductivity of Mg-Si-Zn-Cu alloy through minimizing electron scattering at phase interface

Abstract

The primary cause of the decrease in thermal conductivity of conventional thermal conductive magnesium alloys is electron scattering brought on by solute atoms. However, the impact of phase interface on thermal conductivity of magnesium alloys is usually disregarded. This study has developed a Mg-Si-Zn-Cu alloy with high thermal conductivity that is distinguished by having a very low solute atom content and a significant number of phase interfaces. The thermal conductivity of the Mg-1.38Si-0.5Zn-0.5Cu alloy raises from its untreated value of 133.2 W/(m·K) to 142.2 W/(m·K), which is 91% of the thermal conductivity of pure Mg. This is accomplished by subjecting the alloy to both 0.8wt% Ce modification and T6 heat treatment. The morphology of eutectic Mg2Si phase is changed by Ce modification and heat treatment, and as a result, the scattering of electrons at the Mg2Si/Mg interface is reduced, resulting in increase of the alloy's thermal conductivity.