Investigation of Thermal Conductivity and Mechanical Properties of Mg-4Zn-0.5Ca-xY Alloys

The thermal conductivities of quaternary Mg-Zn-Ca-Y alloys have been investigated by evaluating the effect of adding Y on the Mg-4Zn-0.5Ca alloys, with an emphasis on developing new Mg alloys without compromising their thermal conductivities, processabilities, and mechanical properties. In this study, to improve the mechanical properties of the Mg-4Zn-0.5Ca alloy, Y was chosen as a strengthening element, and the effect of adding Y on the thermal and mechanical properties of the alloy was investigated. The thermal conductivities slightly decreased as the Y-content increased. However, the tensile yield strength and ultimate tensile strength improved as the Y-content increased. In addition, the average spiral flow lengths of the Mg-Zn-Ca-xY alloys were almost the same as that of the Mg-Zn-Ca alloy. The results of this study indicate that Mg-Zn-Ca alloys with more than 1 mass% Y exhibit better mechanical properties and thermal conductivities than gravity-cast AZ91 alloys.