Enhanced wetting behavior using femtosecond laser-textured surface in laser welding-brazing of Ti/Al butt joint

The properties and serviceability of welded-brazed joint of dissimilar materials depend on the bonding quality at the interface, which in turn is affected by the wetting behavior of liquid metal on solid metal. In this paper, the surface of Ti alloy was textured using femtosecond laser to enhance the wetting behavior in laser welding-brazing of Ti/Al butt joint. The morphology and wetting behaviors of the Ti surface fabricated by femtosecond laser texturing were examined for different laser power and structure patterns. It was found that strip pattern fabricated using a laser power of 1.5 W in all the test cases showed the best hydrophilicity with a water contact angle of 4.6°. For the purpose of this work, the femtosecond laser-textured surface was utilized to fabricate the laser welded-brazed Ti/Al butt joint. Based on the results of microhardness and mechanical properties of the joint, it was proved that the femtosecond laser-textured microcosmic morphology on the Ti surface enhanced wetting behaviors and increased the bonding quality.