Influence of the rotary friction welding parameters on the microhardness and joint strength of Ti6Al4V alloys

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.