Modeling and experimental analysis of fiber laser offset welding of Al-Ti butt joints

In spite of great potentiality in aircraft and automotive industries, dissimilar joining of hybrid Al-Ti structures is often challenging because of the unavoidable formation of brittle intermetallic compounds, mixing of molten phases, and large differences in material properties. In this work, dissimilar 2 mm thickness AA5754 and Ti6Al4V butt joints were produced by shifting an Yb fiber laser source on the upper surface of the Ti sheet. Neither filler wire nor groove preparation was adopted. Different working conditions and seam shapes were assessed. Results, characterized in terms of microstructure, micro-hardness, and tensile behavior, showed good characteristics and margins for improvement. The finite element analysis supported the investigation and provided temperature distribution and thermal cycle in the workpiece. The calculation was carried out by ANSYS parametric design language (APDL). Temperatures and seam cross section were detected for validating the model. Numerical output approached experimental results with good accuracy.