Mechanical and Corrosion Behavior of 7075 Al Alloy Processed by Cold Rolling

Due to their high specific strength and low density, 7075 Al alloys are widely used in aerospace applications. However, Al alloys are prone to corrosion and deterioration, and the service life depends on their corrosion resistance. To investigate the corrosion and strengthening mechanisms of the 7075 Al alloy subjected to cold rolling, x-ray diffraction, scanning electron microscopy and transmission electron microscopy were used to characterize the sample microstructure. Compared to the homogenized samples, the ultimate tensile strength of a cold-rolled sample increased from 235 ± 4 MPa to 347 ± 3 MPa when the thickness reduction increased to 50%. The yield strength approached 305 ± 0.4 MPa, and the tensile ductility decreased up to 62.9%. The cold-rolling process resulted in a significant increase in dislocation density and a reduction in grain size. The increased density of grain boundaries and the fragmentation of the precipitates led to a reduction in galvanic coupling with the Al matrix, resulting in the improved corrosion resistance of the 7075 Al alloy. This study provides a suitable approach to enhance both the mechanical properties and corrosion resistance of Al alloys. Graphical Abstract