Effects of cryorolling, room temperature rolling and aging treatment on mechanical and corrosion properties of 7050 aluminum alloy

In this study, effects of cryorolling (CR), room temperature rolling (RTR) and subsequent aging treatment on mechanical and corrosion properties of 7050 aluminum alloy (AA7050) were investigated. After the severe rolling deformation, the ultrafine-grained structure and high-density dislocations are produced in CR and RTR AA7050 alloys. CR AA7050 exhibits higher volume fraction of UFGs and dislocation density compared to RTR AA7050. Both CR and RTR AA7050 alloys follow the precipitation procedure of nucleation, growth and coarsening, while the DSC test shows that CR AA7050 has stronger response to aging treatment and age-hardening effect. CR AA7050 presents higher micro-hardness (253 HV), yield strength (650 MPa) and ultimate tensile strength (685 MPa), while the elongation (2.2%) is less than RTR AA7050 (245 HV, 573 MPa, 613 MPa, 3.5%). The aging treatment can improve the elongation of rolled samples, while the other mechanical properties are gradually decreased with the increasing in aging time. CR and RTR AA7050 sheets show a low corrosion resistance, while CR are beneficial to improving the corrosion resistance of the aged samples.