Abstract
AA7075 high-strength aluminum alloy, which has many applications in the aircraft, marine and automobile industries, happens to be susceptible to stress corrosion cracking (SCC) when exposed to corrosive environments, resulting in reduced service life of the components. Inappropriate fabrication processes may augment this behavior. The fabrication of AA7075 components using conventional fusion welding processes may produce defects that include hot cracking and porosity. Friction stir welding (FSW) is a solid-state joining process that can avoid these problems and being widely used for components made of aluminum alloys. Because the joining occurs at a temperature that is lower than the melting point of the material, solidification cracking defects can be eliminated. This study investigates the SCC behavior of FSW AA7075-T651 joints. Horizontal-type SCC test was conducted on circumferential-notched tensile (CNT) specimens exposed to 3.5 wt. % NaCl solutions under various axial stress conditions. The different regions of the fractured specimens, such as the machined notch, SCC region and region of ultimate mechanical failure were analyzed by scanning electron microscopy (SEM) to establish the mechanism of SCC. The threshold stress of parent metal (PM) and stir zone (SZ) of the FSW joint were found to be 242 and 175 MPa, respectively.
Funding source: Department of Science and Technology (DST), SERB Division, Government of India
Award Identifier / Grant number: SB/FTP/ETA-281/2012 (SR)
Author contributions: All the authors have accepted responsibility for the entire content of this submitted manuscript and approved submission.
Research funding: The authors are grateful to the Department of Science and Technology (DST), SERB Division, Government of India, New Delhi, for the financial support provided under the Fast Track Young Scientist Scheme through a R&D Project No. SB/FTP/ETA-281/2012 (SR).
Conflict of interest statement: The authors declare no conflicts of interest regarding this article.
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