Effect of spiral scan distance on the nanosecond-pulsed-laser lap joint of Al/Cu. (February 2023)

• Record Type: Journal Article
• Authors: Li, Qige; Zhu, Baohua; Li, Haoyue; Niu, Sicheng; Wu, Laijun; Zeng, Zhi; Xia, Hongbo; Chen, Bo; Tan, Caiwang
• Is Part Of: Optics & laser technology. Volume 158:Part B(2023)
• Publication Date: 2023-02
• Subjects: Nanosecond pulsed laser welding -- Al/Cu lapped joint -- Spiral scan distance -- Interfacial microstructures -- Mechanical properties; Optics -- Periodicals; Lasers -- Periodicals; Electronic journals; 621.366
• DOI: 10.1016/j.optlastec.2022.108896
• Languages: English
• ISSNs: 0030-3992

Abstract

Highlights: Nanosecond pulsed laser welding of Al to Cu thin sheets was achieved. Results of interfacial compounds formation at different spiral scan distances were clarified. Highest lap shear force of 107.7 N was obtained at the spiral scan distance of 0.04 mm. Three fracture modes produced at various spiral scan distances were clarified. Abstract: The T2 Cu with a thickness of 0.2 mm and 6063 Al alloy with a thickness of 0.4 mm were joined via nanosecond pulsed laser welding in an inner spiral scanning mode. The lap configuration was Cu (upper)/Al (under). The influence of spiral scan distance (spiral distance for short) on the weld formation, microstructure and mechanical property was investigated. The results showed that circular holes and arc-shaped cracks formed on the weld surface at the spiral distance of 0.02 mm, and these defects disappeared at higher spiral distances. The tendency of porosity increased initially and decreased afterwards as the spiral distance increased. The interfacial morphology exhibited a wave-shaped structure at the spiral distance of 0.02 mm, and a continuous lump θ-CuAl2 phase was produced at the interface. When the spiral distance was larger than 0.02 mm, the wave-shaped structure disappeared and V-shaped areas were generated due to the invasion of Al element into Cu base metal. α-Al and θ-CuAl2 phases were possibly produced in these areas. The Cu-rich areas generated on the sidewall of the weld could cause the formation of θ-CuAl2 . According to the tensile-shear load results, the maximum shear force reached 107.7 N at the spiral distance of 0.04 mm. The satisfactory weld formation and larger effective bounding area contributed to the superior bonding strength. Three fracture modes (button pulling out failure, weld shear failure and interface failure) were observed in this study.