Effect of pre-heat treatment and subsequent ECAP-CU on microstructure and corrosion behavior of 7075 Al alloy fasteners

• Pre-heat treatment (PHT) combined with equal-channel angular pressing and cold upsetting (ECAP-CU) significantly enhances the corrosion resistance of 7075 Al alloy fasteners. • The processed alloy exhibits a low corrosion current density of (6.379±0.025)×10⁻⁶ A/cm² and a corrosion rate of 0.066 mm/year, with intergranular corrosion depth reduced to (557±8) μm. • Microstructural refinement and dissolution of nonequilibrium phases reduce galvanic potential differences, while a denser passivation film forms on the alloy surface in aggressive environments. • This method provides a promising route to simultaneously improve mechanical properties and corrosion resistance, overcoming the limitations of conventional coating technologies.