Microstructure evolution during laser pressure welding of pure aluminum

The present work was undertaken to provide an in-depth insight into a relatively new joining technique, the so-called laser pressure welding. To this end, the fundamental aspects of microstructural evolution occurring during welding of pure aluminum were studied. The microstructural changes were found to be relatively complex involving static recrystallization, melting, solidification and plastic deformation. The solidified grains were deduced to nucleate epitaxially on the recrystallized grains thus inheriting their crystallographic orientations. From thorough microstructural analysis, it was deduced that the solidification process initiated before rolling and thus the freshly crystallized material experienced a plastic strain.