Microstructure and Thermophysical Properties of Mg-Ga Alloys

Abstract

The microstructure and thermal characteristics of Mg-36%Ga, Mg-43%Ga, and Mg-45%Ga(wt%) alloys were investigated. The experimental results show that the microstructure of Mg-36%Ga alloy is mainly composed of primary α-Mg phase and α-Mg+Mg₅Ga₂ eutectic phase, the microstructure of Mg-43%Ga alloy is mainly composed of α-Mg+Mg₅Ga₂ eutectic phase, and the microstructure of Mg-45%Ga alloy is mainly composed of primary Mg₅Ga₂ phase and α-Mg+Mg₅Ga₂ eutectic phase. The melting enthalpies of Mg-36%Ga, Mg-43%Ga, and Mg-45%Ga are 146.41, 171.90, and 113.90 J/g, with the phase change temperature of 422.57, 422.70, and 422.90 °C, respectively. Mg-43%Ga alloy contains the highest melting enthalpy because of the highest content of α-Mg+Mg₅Ga₂ eutectic phase. In addition, the thermal expansion of the three alloys increases with increasing temperature, while the thermal diffusivity and thermal conductivity decreases with increasing content of Ga.

Keywords

Mg-Ga alloy / phase change material / thermal energy storage / latent heat storage