Linear friction welding of Ti-6Al-4V alloy fabricated below β-phase transformation temperature

The interfacial temperature, microstructure and hardness distribution of the linear friction welded Ti-6Al-4V joints obtained at different applied pressures were investigated. The sound Ti-6Al-4V alloy joints were successfully fabricated below the β-phase transformation temperature. The increased pressure considerably decreased the welding temperature. The dynamically recrystallized ultra-fined α equiaxed grains of 0.2 μm were formed in the weld center of the joint by applying pressure of 550 MPa. Moreover, the hardness of the weld center was higher than that of the base material without the softened region in thermo-mechanical affected zone, which suggests the improved mechanical properties of the joints.