High thermal conductivity of highly alloyed Mg-Zn-Cu alloy and its mechanism

The content of alloying elements in most thermally conductive magnesium alloys is as low as possible, and this will lead to lack of alloying effect. In this paper, a Mg-xZn-xCu(x = 1,3,5, wt%) alloy was studied with comparatively high alloying element contents. The thermal conductivity of this alloy declines very slowly with the increment of element concentration. Even with the additive amount of 10 wt% of alloying elements, this alloy can attain a high thermal conductivity of 136.5 W/(m·K). After T6 treatment, the thermal conductivity of Mg-5Zn-5Cu alloy increases to 141.6 W/(m·K). The CuMgZn intermetallic compound are specially prepared to study the thermal conduction mechanism. The results show that the formation of CuMgZn ternary compound in Mg-Zn-Cu alloy consumes massive solute atoms, which makes the thermal conductivity of the alloy insensitive to alloy composition changes.