.5083 Aluminum Surface Mechanical Treatment And Coating Effect

The sand blasting and polishing treatments were used as the pretreatments of the 5083 aluminum alloy before painting. First part of this dissertation was devoted to the study of the change of the adhesive strength between alloy and coating. The second part of this work was on the analysis of the resistance to intergranular corrosion and stress corrosion cracking of the coated alloy.1. After the treatments, the surface residual compressive stress of the alloy respectively increased by 173% and 38.3, which was beneficial to restraining the propagation of the crack.2. Sand blasting and polishing both increased the cleanliness and the roughness of the substrate. Compared to the sample without mechanical treatments, the bonding strength between the coating and alloy respectively increased by 550.6% and 123.2%.3. After the treatments, the resistance to intergranular corrosion (IGC for short) of the coated alloy increased because corrosion medium was set back. The maximum IGC depths of alloys without surface treatments, after sand blasting and polishing treatment was respectively 40,10 and 15μm.4. The resistance to Stress Corrosion Cracking(SCC for short) of the coated alloys improved after mechanical treatments. The resistance to SCC of alloy after sand blasting was best, which was worst without mechanical treatments.