Corrosion behavior of AlCoCrFeNix high entropy alloys

Autor(es)

Zemanate, Ana Maria ; Jorge Junior, Alberto Moreira ; Andreani, Gisele Ferreira de Lima ; Roche, Virginie ; Cardoso, Ratia Regina

• Tipo de documento: Artigo Científico
• Fonte: Electrochimica Acta; v. 441, p. 13-pg., 2023-01-13.

Resumo

In this study, the effects of three different nickel concentrations on the microstructure, hardness, and corrosion properties of AlCrFeCoNix (x = 1.0, 1.5, 2.0) high entropy alloys (HEA) were investigated. The alloys were obtained by arc melting from high-purity raw materials and subjected to heat treatment at 1125 degrees C for 5 h. Microstructural characterization revealed a dendritic morphology for the equimolar and AlCrFeCoNi1.5 alloys, while the AlCrFeCoNi2 alloy presented a hypoeutectic microstructure. Differences in microstructure and chemical composition were observed between the dendritic and interdendritic regions, with clear segregation of Cr in the interdendritic areas. The increase in Ni content and the heat treatment resulted in the formation of the FCC phase, consequently reducing the alloys' hardness. The corrosion properties of HEA were evaluated by potentiodynamic polarization and electrochemical impedance spectroscopy methods in a 3.5% NaCl solution. The results show high resistance to localized corrosion of the alloys, evidenced by the low values of corrosion current densities, and high pitting potentials. The protective film's formation depends on Ni content, which is also related to FCC/BCC ratio and phase compositions. The heat treatment generally results in a more homo-geneous, thicker, and less defective oxide film. (AU)

• Processo FAPESP: 21/06546-1 - Desenvolvimento e produção de liga refratária de alta entropia para aplicação em implantes: propriedades mecânicas, modificação da superfície, bioatividade e comportamento de corrosão
• Beneficiário: Alberto Moreira Jorge Junior
• Modalidade de apoio: Bolsas no Exterior - Pesquisa
• Processo FAPESP: 19/25302-6 - Ligas de alta entropia para armazenamento de hidrogênio
• Beneficiário: Kátia Regina Cardoso
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