Microstructure and Tensile Properties of Titanium Matrix Composite TIG Welded Joint

Discontinuously reinforced titanium matrix composite was welded by tungsten inert gas welding (TIG) technique. The microstructure and tensile properties of the welded joint were studied. The results show that TIG welding can well realize the connection of titanium matrix composite. The weld had the good formation with an even and clean surface, and no welding defects such as microcracks and pores were found. The joint consisted of weld zone, heat-affected zone and base metal zone. The TiB reinforcements distributed on the boundaries of β phase in the weld zone and the heat affected zone near the weld in the joint had high aspect ratios with a high degree of refinement, and there were a large number of acicular matensite α' phase in the two regions. The tensile strength of the joint was 1 137 MPa, 92% of that of the base metal, and the percentage elongation after fracture was 2.20%. The joint fractured at the base metal zone during tensile; the tensile fracture of the joint was mainly characterized by ductile fracture, and local areas showed intergranular fracture features.