Dissimilar laser welding of a CoCrFeMnNi high entropy alloy to 316 stainless steel

In this work, laser welding of a rolled CoCrFeMnNi high entropy alloy to 316 stainless steel was per- formed. Defect-free joints were obtained. The microstructure evolution across the welded joints was as- sessed and rationalized by coupling electron microscopy, high energy synchrotron X-ray diffraction, me- chanical property evaluation, and thermodynamic calculations. The fusion zone microstructure was com- posed of a single FCC phase, and a hardness increase at this location was observed. Such results can be attributed to the formation of a new solid solution (arising from the mixing of the two base materials). Moreover, the incorporation of carbon in the fusion zone upon melting of the stainless steel also aids in the strengthening effect observed. The welded joints presented good mechanical properties, with fracture occurring at the fusion zone. This can be ascribed to the non-favourable, i.e., large grain size, microstruc- ture that developed at this location