Effect of pre-precipitation on localized corrosion properties of 2519A aluminum alloy

The influence of pre-precipitation on tensile mechanical properties, stress corrosion cracking and intergranular corrosion properties of 2519A aluminium alloy was studied. The mechanism was analyzed through microstructure observation by transmission electron microscope. The results show that for 2519A-T6 samples, pre-precipitation can improve localized corrosion resistance. Stress corrosion cracking time by constant load test increases from 1 day (no pre-precipitation) to 9 days (pre-precipitation). Maximum intergranular corrosion depth decreases from 220 mu m to 120 mu m while ultimate tensile strength still remains 400MPa. Localized corrosion properties of 2519A-T8 samples are improved by pre-precipitation. Cracking time prolongs from 10 days (no pre-precipitation) to 14.9 days (pre-precipitation). Maximum intergranular corrosion depth and its corrosion morphology remain unchanged while ultimate tensile strength of pre-precipitation T8-samples is decreased. Proper pre-precipitation can enhance the discontin