Local changes in the microstructure, mechanical and electrochemical properties of friction stir welded joints from aluminium of varying grain size

The present study shows results of friction stir welded (FSW) samples after different plastic deformation routes. welds were made coarse-grained and ultrafine-grained commercially pure aluminium. As a method new hybrid process has been chosen, which resulted in obtaining with characteristics microstructure, also differed dependance the examined plane. Microstructure observations showed that, regardless base material, due to continuous dynamic recrystallization zone was characterized by equiaxial grains an average size 3.5–5.0 μm. However, significant differences changes microstructure thermomechanically affected heat zones have obtained between welds. Microhardness profiles revealed decrease comparison initially deformed samples, but increase for annealed samples. Tensile tests In rupture occurred zone, while undeformed material. addition, application 3D digital image correlation, it possible observe local weld during tensile test. Additionally, electrochemical measurements performed two sizes working electrode, included microcapillary technique. higher corrosion resistance 3.5% NaCl zones.