Transition from Intergranular Corrosion to Intergranular Stress Corrosion Cracking in AA2024-T3
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Citation:Liu, Xiaodong; Frankel, G. S.; Zoofan, B.; Rokhlin, S. I. "Transition from Intergranular Corrosion to Intergranular Stress Corrosion Cracking in AA2024-T3," Journal of The Electrochemical Society, v. 153, no. 2, 2006, pp. B42-B51.
The transition of intergranular corrosion (IGC) to intergranular stress corrosion cracking (IGSCC) in AA2024-T3 was studied using microfocal X-ray radiography, scanning electron microscopy (SEM), and electrochemistry. A constant potential was applied in 1 M NaCl solution, and a fixed elastic tensile displacement was applied in the transverse direction using a modified ASTM G49 jig. In this orientation, IGC grows primarily along the elongated grain boundaries in the longitudinal and transverse directions, parallel to the applied stress. SEM and X-ray radiography provided insightful images of the transition to IGSCC. Linking of the individual IGC sites occurred at the edges of the elongated grains, resulting in transition of the IGC sites into IGSCC that was nominally normal to the applied stress. This coalescence process was discontinuous in nature, as evidenced by arrest marks on the fracture surface and oscillations in the measured current.
This work was supported by the United States Air Force Office of Scientific Research through grant no. F49620-02-1-0148 and FA9559-04-1-0368.