The investigation of keyhole behavior in dissimilar aluminum/titanium interface

Abstract

The in-situ investigation of keyhole behavior is essential for the comprehension of laser beam interaction with dissimilar joint. In the present study, the keyhole behavior at the interface between titanium T40 and aluminum A5754 under a Yb:YAG laser pulse was characterized by high-speed imaging through the quartz plate and by SEM-EDX. The effect of beam offset from the joint line on keyhole geometry and drilling rate, as well as on the elemental mapping and composition of the melted zones was investigated. The SEM-EDX analysis of the deposits left by vapor plume on the quartz plate above the keyhole opening was performed. A strong synergetic effect between the joined materials was observed: the keyhole tended to shift on A5754 having lower vaporization temperature due to the heat transfer from highly absorbing T40. The evolution of keyhole and melted zone features with beam offset was consistent with previously reported behavior of the plume.