Abstract
Dissimilar material welding enables the integration of the superior properties of different materials, thereby achieving optimal structural performance and economic efficiency while meeting specific service requirements. The presence of solid-solution strengthening elements such as Ti, Co, and Al, and trace elements such as P and S, in GH3030 nickel-based superalloy leads to their segregation and the formation of intermetallic compounds in the welded joint, resulting in deterioration of joint performance. High-entropy alloys (HEAs), with their high-entropy effect and delayed diffusion effect working synergistically, can effectively suppress compositional segregation caused by uneven elemental diffusion and the formation of intermetallic compounds at interfaces, thereby improving the quality of welded joints and demonstrating great potential for dissimilar material joining. Therefore, in this study, fiber laser welding was used to effectively join AlCoCrFeNi2.1 eutectic high-entropy alloy and GH3030 nickel-based superalloy, with the expectation to improve welded joint element segregation, suppressing the formation of intermetallic compounds, and enhance the welded joint quality and its performance. The AlCoCrFeNi2.1/GH3030 joint exhibits an average yield strength of 1.31 GPa, which is significantly higher than that of the GH3030/GH3030 joint (1.07 GPa). In addition, the AlCoCrFeNi2.1/GH3030 joint shows a higher average work-hardening exponent of 0.337 compared with 0.30 for the GH3030/GH3030 joint, indicating improved plasticity. The results showed that under appropriate welding process parameters, the hardness of the weld zone, transitioning from the nickel-based superalloy to the eutectic high-entropy alloy, exhibited a stable increasing trend, and the joint exhibits good plasticity, with brittle fracture being unlikely.