Characterization of Laser-Welded Ti Alloy and Stainless Steel Joint Using Cu Interlayer

In this study, Cu was used as an interlayer to restrain the formation of brittle Ti-Fe intermetallics when joining Ti alloy to SS. Microstructures of the joint were analyzed using optical microscopy, scanning electron microscopy and x-ray diffraction. Besides, the tensile strength of the joint was also measured. The melting amount of base materials was controlled by changing thickness of Cu interlayer to control the melting proportion in weld. The melting amount of base materials in weld decreased with the thickness of Cu interlayer. The content of Cu solid solution in weld increased with the thickness of Cu interlayer. Ti-Cu compound layer was formed on the Ti alloy side. The width of the Ti-Cu compound layer increased with the increase in heat input. The tensile strength of joint was largely impacted by Ti-Cu compound layer. The tensile strength of joint first increased and then decreased with the increase in width of the Ti-Cu compound layer.