A new high-strength and corrosion-resistant Al–Si based casting alloy

To improve mechanical properties and particularly corrosion resistance of aluminum high pressure die castings, a new Al–Si based alloy was developed by lowering copper content and optimizing other alloying elements. In comparison with the widely used high pressure die casting A380 and A360 alloys, the newly developed alloy exhibits an improved strength by 20% with respect to A360 and a better corrosion resistance by 45% compared with A380. The improvement in mechanical properties and corrosion resistance of the new alloy is attributed to the dramatic microstructure refinement and eutectic silicon morphology modification with much better homogeneous distribution of the second phase particles in the matrix. ► A new alloy shows strength matching A380 and corrosion resistance similar to A360. ► The corrosion resistance improvement is about 45% compared with A380. ► Mischmetal dramatically refines microstructure and modifies Si morphology. ► Mischmetal improves intermetallic dispersion homogeneity in the matrix.