Effects of drawing strain on grain structure， strength and corrosion resistance of 7075 aluminum alloy

The effect of drawing strain on the microstructure and properties of 7075 aluminum alloy using tensile and exfoliation corrosion tests was investigated， combined with Scanning Electron Microscopy （SEM）， Electron Backscatter Diffraction （EBSD）， and Transmission Electron Microscopy （TEM） analysis. As the drawing strain （ε） increased from 0 to 0.58， the degree of recrystallization continuously increased， and the grain morphology transformed from fibrous to approximately equiaxed； The strength decreased slightly while the elongation improved continuously. The exfoliation corrosion resistance initially improved and then deteriorated with increasing deformation. At a drawing strain of0.09， the grain structure remained fibrous， leading to the maximum corrosion depth at 530 μm； At a drawing strain of 0.17， abnormal grain growth occurred， and discontinuously distributed grain boundary precipitates hinder corrosion propagation， enhancing resistance， so that the maximum corrosion depth was only 386 μm； At drawing strains of 0.36~0.58， fine recrystallized grains （34~53 μm） formed， more high-angle grain boundaries appeared， and grain boundary precipitates coarsened， leading to reduced corrosion resistance with a corrosion depth of 600 μm.