A 4 kg AlCoCrFeNi_(2.2) near-eutectic high-entropy alloy ingot was prepared by vacuum medium frequency induction melting. The effects of homogenized treatment on microstructure and mechanical properties of AlCoCrFeNi_(2.2) were studied. The results showed that all the alloys consisted of the primary FCC phases and eutectic FCC/B2 phases. After homogenized treatment, lots of precipitated phases appeared in the primary phase. The hardness of the as-cast alloy was HV296. The hardness values of samples were decreased and were around HV250 after homogenized treatment. The tensile fracture strength of the as-cast alloy reached 900 MPa, while the elongation was 18%. After homogenized treatment at 900 ℃, the alloy showed the most excellent mechanical properties with the fracture strength 880 MPa and the elongation was 29%, respectively. All the alloys displayed a mixture fracture mechanism, including ductile fracture in primary FCC phases and eutectic FCC phases, and brittle quasi-cleavage fracture in eutectic B2 phases. Through a simple heat treatment method, the strength of the alloy was not reduced but the plasticity was greatly enhanced, which was more conducive to the industrial application prospects.
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