Stress corrosion cracking susceptibility of 7A52 aluminum alloy
(1.北京市装甲兵工程学院工程力学系
2.Institute of Remanufacture Engineering, Academy of Armored Force Engineering, Beijing 100072, China)
2.Institute of Remanufacture Engineering, Academy of Armored Force Engineering, Beijing 100072, China)
Abstract: The stress corrosion sensitivity of 7A52 aluminum alloy was investigated in the artificial sea water through slow stain rate test(SSRT). The stress corrosion cracking(SCC) susceptibility was estimated with the loss of elongation and stress corrosion sensitivity index. The results show that the susceptibility of 7A52 aluminum alloy is always high when the strain rate is in the range of 10-5-10-7 s-1. It reaches the maximum at the strain rate of 8.7×10-7 s-1, and the sensitivity index reaches 0.346. The characteristics of stress corrosion can be observed clearly on the fracture of tensile specimen. The process of SCC is depicted according to the fracture morphology. The SCC initiates at the edge of the specimen. Then the SCC grows rapidly because of the anode dissolving and stress concentration. When the area of specimen cannot support the tensile stress, it ruptures suddenly. The secondary cracks and quasi-cleavage surface can be found on the fracture morphology.
Key words: 7A52 aluminum alloy; stress corrosion cracking(SCC); stress corrosion susceptibility