Study on the thermal storage properties of Al-Si-Cu-Mg alloy

Abstract

Based on thermodynamic calculation technology, the thermodynamic data of six alloys (inc. Al-Si and Al-Si-Cu-Mg systems) was calculated. The microstructure, phase transformation temperature and latent heat of the Al-4%Cu-12%Mg-7%Si alloy and Al-13%Si alloy were also verified by X-ray diffraction(XRD), scanning electron microscopy/Energy-dispersive system (SEM/EDS) and Differential scanning calorimetry (DSC). The results show that The enthalpy change value of Al-Si-Cu-Mg alloy is larger than that of Al-Si alloy from 800 °C to 400 °C, while its phase transformation temperature is lower. In particular, the enthalpy value of Al-4%Cu-12%Mg-7%Si alloy is 85% higher than that of Al-13%Si near eutectic alloy, and its initial temperature of phase transformation is about 74 °C lower. The former has relatively low phase transformation temperature and over-dimensioned latent heat of phase transformation, displaying the excellent thermal storage property. Therefore, the alloy is a good potential solar energy thermal storage material. The results in the paper also indicated that thermodynamic calculation is of value in seeking new potential solar energy thermal storage materials for solar thermal power generation system.