Laser lap welding of TC4 titanium alloy to 6082 aluminum alloy using a CoNiCuNb0.5 V1.5 high entropy alloy filler

To avoid the formation of brittle Ti-Al intermetallics, a new welding procedure for Ti-Al alloy joints was proposed. The feasibility of CoNiCuNb0.5V1.5 high-entropy alloy filler metal for laser lap welding of TC4 titanium alloy to 6082 aluminum alloy is investigated in this paper. By adjusting the welding parameters, a small amount of base material on the titanium side was melted. The high entropy of mixing and kinetic sluggish diffusion effects of high-entropy alloy (HEA) are used to facilitate the formation of solid solution structure, obstruct the mixing of titanium atoms and aluminum atoms and thus inhibit the formation of Ti-Al IMCs. The weld seam without Ti-Al IMCs was obtained. At the high-entropy alloy-Al alloy interface, the joint fractured with a maximum tensile strength of 190 MPa.