Characterization of Intermetallics Formation in µFSSW of Dissimilar Al/Cu Alloy Sheets

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Conference Proceeding

Publication Title

Minerals, Metals and Materials Series



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Electric vehicle battery packs consist of a large number of battery cells which must be assembled together with robust mechanical and electrical joints. One of the challenges is to join highly conductive and dissimilar multilayer materials such as Al to Cu alloy sheets with 100% reliability. Micro-friction stir spot welding (µFSSW) is a spot-like joining process utilizing a non-consumable tool to generate frictional heat and join multilayer materials under the solid-state condition, which makes the µFSSW a strong candidate for joining dissimilar Al/Cu sheets to manufacture various types of battery interconnects. However, investigations to the dissimilar µFSSW of ultra-thin Al to Cu alloy sheets (<500 µm) are limited. This paper presents experimental investigations on intermetallics (IMCs) formation in µFSSW of ultra-thin Al to Cu sheets. Accordingly, a series of µFSSW of dissimilar 400 µm ultra-thin 6061Al-T6 to Cu-Astm B370 sheets trials were conducted and the stir zone temperature was measured. The obtained weld cross sections were characterized by scanning electron microscopy (SEM) equipped with energy dispersive X-Ray spectroscopy (EDS). The effect of µFSSW conditions on the weld zone IMCs formation was evaluated. It has been found that the IMCs formations are closely related to the processing temperature, which is decided by the tool dwell time in this present study.


Al to Cu alloy sheets, Dissimilar joining, Intermetallics, Micro-friction stir spot welding, Microstructure


Aviation and Technology