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 (R) 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 degrees 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. (C) 2017 Elsevier B.V. All rights reserved.