Effect of microalloying element addition on the microstructure, mechanical and corrosion behaviour of A356 secondary alloy with 0.30% Fe

This work investigated how trace additions of Mn, Cr and V affect the morphologies of harmful BETA-AlFe5Si intermetallics, mechanical properties and corrosion behabior of A356 secondary alloy with an iron content of 0.30wt%. The needle shaped BETA-intermetallics are replaced by a Chines script ALFA-compund when Mn, Cr and V are added. The mechanical properties of A356 secondary alloys were improved by the modifications of the BETA-intermetallics into ALFA-iron compounds. The corrosion behavior of the modified secondary alloy was similar to both, the A356 primary and the unmodified secondary alloys. Thus, small additions of Mn, Cr and V improbe the mechanical properties without negatively affecting the corrosion resistance of A356 secondary alloy.