Addition of rare earth elements for improving the tensile properties of aluminum alloys has attracted great attention.In this study,a systematic analysis on the microstructure and tensile properties of A356-0.13Ti alloys with different contents of scandium(Sc)and scan-dium/zirconium(Sc/Zr)after solution and aging treatment process was carried out.The addition of Sc/Zr into A356-0.13Ti alloys can greatly refine the grain size and modify the deleterious coarse eutectic Si structure and harmful acicular iron-containing phase morphology.As a result,the maximum value of strength(298 MPa)and ductility(elongation of 8.4％)are acquired by co-addition of Sc/Zr after solution and aging treatment process,which indicates that the tensile properties of A356 alloy are greatly enhanced by the synergistic effect of co-addition of Sc/Zr.