Study on Corrosion Performance of Friction Stir Processed AA6082-4 wt.% Al3Zr In Situ Composites

The 4-mm AA6082-4 wt.% Al3Zr in situ aluminum matrix composites were processed by friction stir processing. The grain morphology and grain boundary characteristics of the aluminum matrix composites before and after friction stir processing were studied by electron backscatter diffraction and orientation imaging analysis software, and the corrosion behavior of the composites was also studied. The results show that during friction stir processing, the metal undergoes thermoplastic deformation, and the coarse grains of the base metal are refined. The dislocations in the grains are blocked and recombined, and shear texture and deformation substructure are formed simultaneously. With the refinement and dispersion of reinforcement particles (Al3Zr) after friction stir processing, the ability to reduce the corrosion rate of composites in NaCl solution is improved, the distribution uniformity and stability of passivating film are improved, and the corrosion current density in electrochemical corrosion process is reduced. When the rotating speed is 1200 r/min, the corrosion current density decreases from 5.06 x 10(-6) to 1.19 x 10(-6) A/cm(2). The corrosion potential of the stirring zone is about - 609 to - 580 mV, and the corrosion voltage of the base metal zone is about - 52 to - 494 mV. After 14 days of immersion testing, the average depth of the corrosion pit is 12.9 mu m.