Effect of Electron Beam Oscillation Welding of Molybdenum and Titanium

Abstract

Electron beam welding of pure molybdenum (Mo) and titanium alloy (Ti-6Al-4V) was performed with beam oscillation. The effects of beam oscillation with offset on the welded joints were analyzed in terms of microstructure, element distribution, chemical composition, microhardness, and tensile strength. The results showed that the fusion zone expanded with beam oscillation. Reaction layers were generated in both joints welded with and without beam oscillation. The thickness of the reaction layers decreased along the perpendicular direction. The reaction layers were (Mo, Ti) solid solutions. Both welded joints consisted of single-phase Mo, the β-Ti phase, and Mo-Ti solid solutions. The microhardness distribution of the joint welded with beam oscillation was more consistent than that of the joint welded without beam oscillation, and the maximum hardness was reduced from 340 HV to 270 HV. The tensile strength increased from 124 MPa to 204 MPa.