Microstructural and Mechanical Properties of AlCoCrFeNi2.1 Alloy Welded Joint by Vacuum EBW

The eutectic high-entropy alloy AlCoCrFeNi 2.1 has excellent mechanical and high-temperature properties. To investigate its potential in the field of welding, electron beam welding was performed. The effect of the electron beam welding power on the morphology of the joint was studied, and the process parameters of the best defect-free joint were finally obtained. XRD confirmed that no new phases were generated before and after welding and that the structure was finer after welding. The microstructure and mechanical properties of the most excellent welded joints were also investigated. Most of the fusion zone (FZ) structure has a finer but somewhat more oriented lamellar organization compared to base material (BM). The hardness was also increased by 15% compared to BM because of the increased percentage of BCC structure in FZ and the reduction of grain size from 1.28 μm to 0.35 μm. The tensile strength and elongation of the joints with this process parameter reached 873 MPa and 22.8%, respectively, accounting for > 90% of the BM, and fracture occurred at the fusion line. Electron beam welding was shown to be a more suitable welding method for this eutectic high-entropy alloy.