Characterization of Pulsed Laser Welded Titanium Alloy and Stainless Steel Joint Using Nb as Interlayer

Herein, Nb is used as an intermediate layer to assist the pulsed laser welding of titanium (Ti) alloy/stainless steel (SS), and the formation of brittle Ti–Fe intermetallics is prevented. Microstructures of the joints are analyzed by means of scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), transmission electron microscope (TEM), and X‐ray diffraction (XRD). Mechanical properties of the joints are evaluated by tensile tests. The laser is concentrated on the side of the Ti alloy, and the formation of the Ti–Fe intermetallics is avoided due to the unmelted Nb. A eutectic reaction occurs at the Nb–SS interface to form a reaction layer. The width of the reaction layer increases as the heat input increases. Reasonable control of laser offset and laser current can keep the thickness of the Nb–Fe composite layer at a low level to obtain a small amount of Nb–Fe intermetallics, thereby improving the mechanical properties of the reaction layer.