Investigation on the pretreatment groove of metal surface of the aluminium alloy/polycarbonate friction stir lap welding

Abstract

Friction stir welding (FSW) emerges a broad application and development prospects in the joining of dissimilar materials. Friction stir lap welding (FSLW) of 6061-T6 aluminium (Al) alloy sheet with different depths groove pretreatment and polycarbonate (PC) sheets is investigated. Weld surface defects are studied by visual inspection. The analyses of microstructures and mechanical tensile properties of the dissimilar joints are carried out by optical microscopy (OM) and tensile tests. Results indicate that the groove depth is a significant factor affecting the welding surface morphology. Tensile strength reaches the maximum with the average value of 29.05 MPa at the groove depth of 0.2 mm, which is equivalent to 58% of the PC base material strength. Microstructure analysis indicates that the molten PC and Al alloy fragments flow along the groove at the action of the pin tool. Simultaneously, Al alloy fragments are inserted into the molten PC material. The two materials form a compact mixed structure, which improves the tensile strength.

Keywords:

• Friction stir lap welding
• aluminium alloy
• polycarbonate
• grooving pretreatment

Acknowledgements

This work was supported by the National Science Foundation of China under Grant [52005071, 51875072]; Natural Science Foundation of Liaoning Province under Grant [2022-MS-342]; and Liaoning Provincial Department of Education General Project under Grant [LJKZ0478].

Author contributions

Yibo Sun: conceptualization and writing original draft; Weibo Wang: investigation and methodology; Haiwei Long: experimental data curation and manuscript review; Yuan Zhang: validation; Jianning Zhu: supervision; Xinhua Yang: project administration; Libin Fu: resources.

Disclosure statement

No potential conflict of interest was reported by the author(s).

Additional information

Funding

This work was supported by the National Science Foundation of China under Grant [52005071, 51875072]; Natural Science Foundation of Liaoning Province under Grant [2022-MS-342]; and Liaoning Provincial Department of Education General Project under Grant [LJKZ0478].