Laser brazing of a nickel-based superalloy using a Ni-Mn-Fe-Co-Cu high entropy alloy filler metal

In this study, we demonstrate the successful brazing and superior mechanical performance of laser brazed Inconel® 718 using a Ni-Mn-Fe-Co-Cu high entropy alloy filler metal with a nominal Ni:Cu:Co:Fe:Mn molar ratio of 1:1:1:0.25:1.75. A maximum 220 MPa shear strength is achieved. The high entropy alloy experiences the hardness increases 3-4 times after brazing. If the brazing temperature is higher than 1200 °C, the bonding strength suffers due to excessivediffusion between the base metal and the filler metal. The hardness behavior is attributed to a combination of the cocktail effect and lattice distortion induced by brazing.