Abstract
TC21 titanium alloy is a new high damage-tolerant structural material for aerospace applications; its welding performance is very critical for the manufacturing of structural parts. In this research, the inertia friction welding (IFW) process of TC21 alloy was conducted, and the microstructure and mechanical properties of IFW joints were investigated. In tensile tests, specially designed tensile samples with grooves were utilized to achieve the tensile properties of IFW joints. The results show that the microhardness and tensile strength of IFW joints are higher than that of the base metal, but the plasticity of joints is worse compared with the base metal. The SEM results reveal that the weld zone has a dynamic recrystallization microstructure with uniform fine-needle α phases. The microstructure evolution in the weld is the key factor that results in the change of the mechanical properties of TC21 IFW joints.