Comparison of Mechanical and Corrosion Properties Between Coarse-Grained and Ultrafine-Grained High-Strength Aluminum Alloys

Multi-axial forging (MAF) and aging were employed to process a high-strength aluminum alloy. The tensile properties, microstructure, and corrosion behavior were researched. After MAF, the strength of the alloy was observably increased, but the elongation was decreased. The strengthening mechanism resulted from dislocation multiplication and grain size reduction. After aging, strength was enhanced further, and elongation was improved. The strength and elongation are 561 MPa and 12.3%. Moreover, the corrosion resistance was obviously enhanced. The further strengthening is mainly attributed to the precipitation strengthening. The larger size and discontinuous distribution of grain boundary precipitates resulted in the alloy having higher corrosion resistance.