The effect of AlFeSi intermetallics compounds morphology on the corrosion behavior of Al–Mg–Si alloy laser welds

This work investigated the relationship between the morphology of AlFeSi intermetallics compounds (IMCs) and grains, and its influence on the corrosion behavior of the surface of Al–Mg–Si alloy laser welds. Due to the segregation of solute elements on the grain boundary, coarse AlFeSi IMCs were more likely to precipitate along the grain boundary. As a result, the “linear-like” AlFeSi IMCs was only found along the straight grain boundary of columnar grains, leading to the deterioration of corrosion resistance, but for the equiaxed grains, only small rod-like AlFeSi IMCs was along the grain boundary. Compared to the small rod-like AlFeSi IMCs at GBs of equiaxed grains, the “linear-like” AlFeSi IMCs at the straight GBs of columnar grains increased the interface area between α-Al, leading to a more evident intergranular corrosion at columnar boundary.