Stress corrosion resistance of 6082 aluminum alloy at different temperatures

The slow strain rate tensile test method was used to study the stress corrosion resistance of 6082 aluminum alloy sheet at different temperatures. The microstructure was observed using optical microscopy and transmission electron microscopy, and the fracture surface was analyzed using scanning electron microscopy. The results show that the stress corrosion sensitivity index of 6082 aluminum alloy sheet was 6.6% in a 3.5% (volume fraction) NaCl solution at 70 ℃,and 2.3% in a 3.5% (volume fraction) NaCl solution at 50 ℃. The fracture surfaces of the samples showed no stress corrosion characteristics, and dispersed small Mg₂Si phases were precipitated within the alloy grains, while discontinuous Mg₂Si phases were precipitated at the grain boundaries, which could not form continuous intergranular corrosion channels. The samples exhibited good stress corrosion resistance. The increased in temperature led to a significant decrease in the tensile strength of the sample in the corrosive solution, resulting in a higher stress corrosion sensitivity index of the sample at 70 ℃.