Significant ductility enhancement for high thermal conductivity Mg-2Sn-2.3La alloy via Zn addition

Herein, we introduced a trace amount of Zn into a high-thermal conductivity (HTC) MgSnLa-based alloy and prepared HTC MgSnLaZn alloy with large ductility as well as high strength by a carefully-designed rolling and annealing process. The elongation and strength of the as-annealed MgSnLaZn alloy are 28 % and 215 MPa, respectively, which are increased by 60 % and 16.9 %, respectively, compared with the MgSnLa-based alloy. Addition of Zn converts the Mg12La phase into the τ1 phase and partly dissolved into the matrix, resulting in slight decrease in electrical conductivity (about 3.5 W/(m-K)), but effectively enhancing the tensile properties. The purity of matrix and the fine dispersed precipitation phases ensure that the electrical and thermal conductivity is close to that of pure magnesium. Non-basal texture characteristics and weak texture intensity are the key factors for improvement in ductility.