High-strength AlCoCrFeNi2.1 eutectic high entropy alloy with ultrafine lamella structure via additive manufacturing

• Published in: Materials science & engineering. A, Structural materials : properties, microstructure and processing Vol. 854; p. 143816
• Main Authors: Chen, Xinsheng, Kong, Jian, Li, Jianliang, Feng, Shuai, Li, Hang, Wang, Qipeng, Liang, Yuzheng, Dong, Kewei, Yang, Yang
• Format: Journal Article
• Language: English
• Published: Lausanne Elsevier B.V 27.09.2022; Elsevier BV
• Subjects: Adhesive wear; Body centered cubic lattice; Chemical precipitation; Composite structures; Ductility; Elongation; Entropy; Eutectic alloys; Eutectic high entropy alloy; Face centered cubic lattice; Grain boundaries; High entropy alloys; High temperature; Intermetallic phases; Lamella; Lamellar structure; Laser beam melting; Mechanical properties; Microstructure; Precipitates; Room temperature; Selective laser melting; Temperature; Tensile behavior; Tribology; Ultimate tensile strength; Ultrafines; Wear behavior; Wear mechanisms; Yield strength; Yield stress; Tensile behavior; Eutectic high entropy alloy; Selective laser melting; Microstructure; Wear behavior
• ISSN: 0921-5093; 1873-4936
• DOI: 10.1016/j.msea.2022.143816

AlCoCrFeNi2.1 eutectic high entropy alloy (EHEA), with its unique in-situ composite structure, not only overcomes the shortcoming of insufficient strength for face-centered-cubic (FCC) single-phase high entropy alloy (HEA), but also overcomes the shortcoming of insufficient ductility for body-centered-cubic (BCC) single-phase HEA, thus attracting widespread attention from the academic community. In this study, AlCoCrFeNi2.1 EHEA with a fully nano-lamella structure was prepared by selective laser melting (SLM). Furthermore, massive L12 and BCC nano-precipitates were precipitated out from the FCC and B2 phases, respectively. Compared to AlCoCrFeNi2.1 EHEA prepared by traditional methods, the SLM-ed EHEA sample shows excellent strength and ductility synergy, with the yield strength, ultimate tensile strength and uniform elongation determined as 1329 ± 12 MPa, 1621 ± 16 MPa and 11.7 ± 0.5%, respectively. The strengthening contributions to the high yield strength of the sample come from nano-lamella structure, grain boundaries, dislocations and nano-precipitates. In addition, wear behavior at room temperature and elevated temperatures of the SLM-ed EHEA sample have also been studied. The tribological property is substantially enhanced with increasing temperature from room temperature to 700 °C due to the transformation in wear mechanism from adhesive wear to oxidative wear. •AlCoCrFeNi2.1 EHEA with ultrafine-lamellar structure was successfully prepared by SLM.•SLM-built EHEA shows an ultra-high tensile strength of ∼ 1.62 GPa together with the uniform elongation of ∼ 12%.•Massive L12 and BCC nano-precipitates were precipitated out from the FCC and B2 matrix, respectively.•The tribological property of SLM-built EHEA was reported for the first time.