Comparative study on experimental and numerical investigations of laser beam and electron beam welded joints for Ti6Al4V alloy

Abstract

This paper reports a numerical and experimental investigation of laser beam welding (LBW) and electron beam welding (EBW) for the Ti6Al4V titanium alloy. The microstructure of LBW and EBW welded joints is compared. A defect-free, fine-grain, and high-quality joint is produced using the EBW process, while undercut and some pores are observed in the LBW welded joint. The simulated temperature distribution and the cross section of the experimental specimen are compared to evaluate the model validity. The calibrated model is applied to determine the thermal cycles on three selected nodes for both LBW and EBW processes. It is observed that the energy density of the electron beam is higher than that of the laser beam, which causes the weld-seam width of the EBW to be larger than that of the LBW weld seam. Narrow weld-seam, fine grain, and no defect make the EBW a more suitable method to join Ti6Al4V titanium sheets compared with the LBW process.