Dissimilar Joining of TC4 Alloys to 304 Stainless Steels Using a Novel V/CuCrZr Composite Interlayer

Laser metal deposition of pure vanadium (V) powder was conducted on TC4 alloys base material to produce an in situ V/Cu composite interlayer for dissimilar welding of 304 stainless steels to TC4 alloys. A sound TC4/304 SS joint is obtained using the prepared V/Cu composite interlayers. The microstructure, microhardness, and tensile properties of the TC4/304 SS joints were investigated. (β-Ti, V), (V), and (Cu) solid solutions are found in the fusion zone near the TC4 alloy side, and (Cu) and (γ-Fe) solid solutions are observed in the fusion zone near the 304 SS side. The maximum ultimate tensile strength of 421 MPa and an elongation at fracture of 4.5% are obtained in the TC4/304 SS joints among the three tensile specimens. The fracture of the welded joints occurs in the heat-affected zone of the unmelted CuCrZr zone instead of the fusion zones due to the coarsening grains. The “bite” connection between FZ1 and CuCrZr plays an important role in improving the tensile strength of the welded joint.