Vapor plume and melted zone behavior during dissimilar laser welding of titanium to aluminum alloy

The present study deals with continuous Yb:YAG laser welding of pure titanium to aluminum alloy A5754 performed with different beam offsets to the joint line. Spectroscopic and morphological characterization of vapor plume exiting the keyhole was combined with post-mortem observation and energy-dispersive X-ray spectroscopy (EDX) analysis of the welds. The laser beam centered on the joint line resulted in periodic transversal inclination of a vapor jet on the aluminum side associated with a local increase of melt width and an intense spatter formation. Such behavior can be attributed to the instability of the keyhole wall from the aluminum side. The beam offset on the titanium side led to …