Influence of Sand Blasting Treatment on Stress Corrosion Cracking and Pitting Corrosion Properties of A7N01 Aluminum Alloy

The influence of sand blasting treatment on the stress corrosion cracking (SCC) property and pitting property of A7N01 aluminum alloy was investigated by slow stain rate test (SSRT) and circular polarization test. The results showed that the SCC sensitive indexes (I_SSRT) and SCC sensitivity of treated alloy in 3.5% NaCl was higher than those of untreated alloy. The pitting potential (E_b) and protective potential (E_p) of treated alloy were lower than those of untreated alloy and the area of hysteresis loop was larger. With increasing the soaking time, E_b and E_p shifted negatively and the area of hysteresis loop increased. This implied that the anti-pitting property and self-repairing property of A7N01 alloy decreased after sand blasting treatment. The treatment made the surface layer microhardness increase and the surface grains refine. However, the treatment led to the increase of surface roughness and the formation of micro-cracks on surface, which was harm to the anti-corrosive property of A7N01 Al alloy.