Thermodynamic prediction of thermal diffusivity and thermal conductivity in Mg-Zn-La/Ce system

Basic thermal properties and mechanical properties are critical parameters for the structural magnesium alloys. Solute atoms and second phases can improve mechanical properties, but are deteriorating the heat dissipation performance. Through experimental determination of alloys, it is found that REMg 12 phases have fewer negative impacts on thermal diffusivities than Tau 1 phases. With the same intermetallic compound, the solute atom Zn have more negative influences on thermal diffusivities of Mg-Zn-La/Ce alloys than the content of second phases. In order to quantitatively evaluate thermal conductivities and further design Mg alloys with both high strength and high thermal conductivity, a calculated method is provided to describe the thermal diffusivity of alloys as a function of alloy composition and phase constitution. A set of parameters for expression of thermal diffusivity of Mg-Zn-La/Ce alloys were obtained through assessing the experimental data. The thermal conductivities of Mg-Zn-La/Ce system were predicted and agreed well with experimental values with calculation error of 1.6% and standard error of +/- 3.0 W/(m K). The calculation method considering thermal diffusivity resistivity improves the calculation accuracy and would be physically significant. (c) 2022 Published by Elsevier Ltd on behalf of The editorial office of Journal of Materials Science & Technology.

Automated summary

Basic thermal and mechanical properties are crucial for structural magnesium alloys. Solute atoms and second phases can enhance mechanical properties but degrade heat dissipation performance. Experimental findings suggest that RE-Mg 12 phases have a lesser negative impact on thermal diffusivities compared to Tau 1 phases.