Effects of multi-modification of rare earth oxides PrxOy and LaxOy on microstructure and tensile properties of casting Al-Cu alloy

Through multi-modification with PrxOy and LaxOy, the tensile strength and elongation of casting Al−Cu alloy can reach to 580 MPa and 10.5%, increased by 26% and 50% respectively than those of the unmodified alloy. Simultaneous increase in the tensile strength and elongation of the multi-modified alloys is suggested to be induced by the refined α-Al dendrites, the formation of Al−RE intermetallic compounds at the grain boundaries, and the most important, more homogeneously distributed nano-scale θ′ precipitates with higher diameter/thickness ratio.