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.