Effect of thermal cycling on the microstructure and mechanical properties of AlCoCrFeNi2.1 high-entropy alloy fabricated using powder plasma arc additive manufacturing

• AlCoCrFeNi 2.1 high-entropy alloy was fabricated by PPA-AM method. • The B2 phase precipitates at the bottom region of the HEA due to thermal cycling. • The ductility of the HEA increases and the strength decreases due to thermal cycling. High-entropy alloys (HEAs) are a novel class of materials. In this study, the AlCoCrFeNi 2.1 HEA was prepared using powder plasma arc additive manufacturing (PPA-AM). The influence of thermal cycling in the PPA-AM process on AlCoCrFeNi 2.1 HEA was investigated. The AlNi elements in the FCC phase in the bottom region were aggregated by thermal cycling to form the acicular B2 particles. This weakened the solid solution strengthening effect of the FCC phase, reduced its yield strength (421 to 389 MPa), and improved its ultimate tensile strength (929 to 981 MPa) and elongation (15.6% to 21.0%). The results of this study might have reference significance for the AlCoCrFeNi alloy system.