Laser-induced pre-placed copper layer titanium-steel joint forming and microstructure research

During the explosive forming of titanium-steel composite plates, defects such as incomplete fusion may occur. Currently, the accuracy, quality, and level of automation in using arc welding for repair are relatively low. The main difficulty lies in the high-quality preparation of the copper transition layer on the steel surface. In this study, a method that utilizes semiconductor laser coaxial powder feeding was proposed to accurately form the Cu transition layer, followed by TIG cladding of a Ti layer on the surface of the Cu layer to achieve localized repair of the composite plate. Using the established semiconductor laser cladding experimental system, the influences of laser power, powder feeding speed, and scanning speed on the cladding parameters and microstructure of the Cu layer were analyzed. After TIG cladding of the Ti layer on the Cu layer surface, a well-formed Ti-Cu-Fe joint was obtained through process optimization, and its microstructure was tested and performance evaluation. The results indicate that :The use of semiconductor lasers enables precise control of the copper cladding thickness, achieving a thickness range of 0.236 ~ 0.462 mm; Energy dispersive spectrometer (EDS) analysis of the Cu-Fe joint reveals that controlling the copper layer thickness significantly reduces Fe content in the upper surface region, thereby suppressing the formation of brittle Fe-Ti intermetallic compounds;After TIG surfacing of the titanium layer, the joint primarily consists of CuTi₂ intermetallic compounds, exhibiting an average shear strength of 194 MPa with a brittle fracture mode.