Fig. 2
From: Pre-weld friction stir processing mitigates hot cracking and strengthens AA6061 fusion welds
Welding on un-treated on AA6061-T6: (a) Overview of the weld, bead-on-plate weld exhibiting showing a prominent longitudinal crack. The schematic highlights the transverse metallographic cross-sections (indicated by green arrows) and the fracture surface (indicated by blue arrows). (b–c) Light optical microscopy (LOM) images of the weld cross-section. (d) LOM micrographs revealing macro/micro-cracks and porosity. (e–f) SEM fractography of the crack surface.
