In this study, Ti6Al4V rods were butt-welded by rotary friction welding. The experimental results show that the weld quality, in terms of the tensile strength and hardness, decreases radially. Therefore, the radius of the welded parts that are viable for rotating friction welding is limited because the areas located far from the centre of the axis have poor mechanical properties. The parameter that impacts the tensile strength and microhardness the most during rotary friction welding of Ti6Al4V is the axial pressure, which includes the friction pressure and forging pressure. A high forging pressure produces fine, equiaxed, and recrystallized grain structures in the welded joint, resulting in a high tensile strength and microhardness. In addition, an increased forging pressure can be used in rotary friction welding to reduce the radial differences in the mechanical properties of the welded joints.

The selection of high-strength titanium alloys has an important role in increasing the performance of aerospace structures. Fabricated structures have a specific role in reducing the cost of these structures. However, conventional fusion welding of high-strength titanium alloys is generally conducive to poor mechanical properties. Friction welding is a potential method for intensifying the mechanical properties of suitable geometry components. In this paper, the rotary friction welding (RFW) method is used to study the feasibility of producing similar metal joints of high-strength titanium alloys. To predict the upset and temperature and identify the safe and suitable range of parameters, a thermomechanical model was developed. The upset predicted by the finite element simulations was compared with the upset obtained by the experimental results. The numerical results are consistent with the experimental results. Particularly, high upset rates due to generated power density and forging pressure overload that occurred during the welding process were investigated. The performances of the welded joints are evaluated by conducting microstructure studies and Vickers hardness at the joints. The titanium rotary friction welds achieve a higher tensile strength than the base material.