Influence of sampling orientation on stress corrosion cracking resistant behavior of 2124 aluminum alloy containing Sc

The stress corrosion cracking behavior of the novel 2124 aluminum alloy containing Sc with different sampling orientations in 3.5%NaCl(mass fraction) solution was studied by optical microscopy and scanning electron microscopy. Furthermore,the morphologies at the crack tip before and after corrosion were analyzed. The results show that the anodic dissolution occurs first during the stress corrosion,and the cooperation of the wedging action incured by the mass of corrosion products gathering at the grain boundaries and the applied stress drives the pre-cracks extending along the grain boundaries to the depth direction further in the corrosive medium. Obvious intergranular corrosion of the samples of the two orientations occurs under the total immersion corrosion and stress corrosion cracking takes places easily. The stress corrosion crack propagation law and the stress corrosion intensity factor threshold of the samples of different orientations are obtained. The effect of the sampling orientation on the stress corrosion cracking behavior was investigated.