Influence of Welding Speed, Voltage, and Beam current on the microstructure and mechanical properties of Electron Beam-Welded Titanium radial joints

Abstract

Welding of Titanium and its alloys is always a stimulating research area due to their special weldability characteristics and extensive usage in various sectors including aerospace, biomedical and industrial applications. During the welding, prediction of the bead geometry is critical for the performance under real time service conditions. The current work is aimed at the investigations of mechanical properties of Ti6Al4V radial welded joints using electron beam welding. Based on the experimental trials the beam current was selected between 5 and 25 mA, voltage between 45 and 60 kV, and welding speed between 0.8 and 1.2 m/min with an objective of obtaining the required depth of penetration. Several experiments and tests were performed for bead geometry, microstructure, hardness, and tensile test. The results from the Grey relational analysis revealed the optimal parameter combination as voltage 45 kV, beam current 25 mA, welding speed 1.2 m/min. The microstructure studies revealed the formation of slightly elongated alpha phase in the base metal and transformed beta phase. Segregation of alloying elements was identified at the fusion zone respectively. The ultimate tensile strength and yield strength were in accordance with the bead geometry. The hardness is higher at the fusion zone than the base metal due to the high-density dislocations.