Dissimilar gas tungsten arc welding of an AlCoCrFeNi high entropy alloy to 316 L stainless steel

High entropy alloys (HEAs) are unique and novel materials with remarkable properties that render them competitive for developing key engineering applications within modern engineering sectors. In the present study, a AlCoCrFeNi HEA was gas tungsten arc welded to 316 L stainless steel, with the aim of assessing the compatibility in terms of microstructure and mechanical performance. These dissimilar joints was obtained with a torch speed of 3.5 mm/s and a current intensity of 90 A under a protective Argon atmosphere. Subsequently, a thorough evaluation of the relationship between processing parameters, microstructure and properties was performed via optical and electron microscopy, atom probe tomography, synchrotron X-ray diffraction, microhardness mapping and tensile testing. The results reveal that the AlCoCrFeNi HEA can be successfully welded with 316 L stainless steel, producing a high-quality and reliable joint, where a gradual microstructural variation is observed across the interface. A good balance of a high tensile strength of ≈568 MPa and fracture strain of ≈11.7% was obtained, with fracture occurring in the fusion zone, highlighting the potential of these dissimilar joints for critical structural applications.