Dissimilar laser welding of an as-rolled CoCrFeMnNi high entropy alloy to Inconel 718 superalloy

Abstract

In this work, dissimilar laser welding between an as-rolled CoCrFeMnNi high entropy alloy (HEA) and Inconel 718 Ni-base superalloy was successfully performed. Defect-free joints with a tensile strength of 822 MPa and a fracture strain of 7.1 % were obtained. The microstructural analysis was conducted using scanning electron microscopy (SEM), electron backscattered diffraction (EBSD), energy-dispersive X-ray spectroscopy (EDS) and high energy synchrotron X-ray diffraction (SXRD), complemented by thermodynamic calculations using the CalPhaD methodology. Mechanical assessment of the joints was conducted via microhardness mapping and tensile testing, allowing to unveil processing-microstructure-properties relationships. Although the precipitation of the Laves phase was identified within the fusion zone, our results reveal the excellent dissimilar weldability between the two alloys, allowing the deployment of this dissimilar material pair for structural applications.