AlCoCrFeNi high-entropy alloy coatings prepared by gas tungsten arc cladding: Microstructure, mechanical and corrosion properties

• Published in: Intermetallics Vol. 138; p. 107337
• Main Authors: Fan, Qingkai, Chen, Chao, Fan, Chenglei, Liu, Zeng, Cai, Xiaoyu, Lin, Sanbao, Yang, Chunli
• Format: Journal Article
• Language: English
• Published: Barking Elsevier Ltd 01.11.2021; Elsevier BV
• Subjects: Arc cladding; B2 structure (crystals); Cladding; Coating; Corrosion; Corrosion resistance; Corrosive wear; Creep strength; Electrochemical impedance spectroscopy; Electron backscatter diffraction; Electron microscopes; Grain boundaries; Grain size; High entropy alloys; Intergranular corrosion; Low carbon steels; Mechanical properties; Microhardness; Microstructure; Morphology; Nanoindentation; Open circuit voltage; Optical microscopes; Protective coatings; Room temperature; Solid phases; Solid solutions; Specific heat; Substrates; Wear resistance; High-entropy alloys; Arc cladding; Coating; Corrosion; Microstructure; Nanoindentation
• ISSN: 0966-9795; 1879-0216
• DOI: 10.1016/j.intermet.2021.107337

Gas tungsten arc (GTA) cladding has the advantages of flexibility, low cost, and high quality. AlCoCrFexNi (x = 1.0, 1.4, 2.1, 3.0, denoted as S-150, S-160, S-170, S-180, respectively) HEA coatings are prepared by GTA cladding on a low carbon steel substrate using different specific heat input (cladding current). The microstructure and phase structure are investigated by optical microscope (OM), scanning electron microscope (SEM), X-ray diffraction (XRD), transmission electron microscope (TEM), electron backscattered diffraction (EBSD). The mechanical properties are investigated by microhardness, nanoindentation. The corrosion properties are investigated by open circuit potential (OCP), potentiodynamic polarization, and electrochemical impedance spectroscopy (EIS). The results show that the coating alloys mainly contain an A2 + B2 structure, and the grain boundaries of S-150 are Cr-rich σ phase. With the increase of specific heat input, the grain size becomes larger and the morphology changes from equiaxed to columnar. S-180 displays lower hardness and more active room-temperature creep deformation than S-150, which is attributed to the reduction in grain boundary strengthening, solid solution strengthening, and precipitate strengthening. S-180 displays better corrosion resistance than S-150. The typical corrosion type of S-150 and S-180 is pitting corrosion and intergranular corrosion, respectively This research contributes to the fabrication of large-thickness and large-area corrosion-resistant and wear-resistant HEA coatings. [Display omitted] •AlCoCrFexNi (x = 1.0, 1.4, 2.1, 3.0) HEA coatings are prepared by gas tungsten arc cladding.•AlCoCrFeNi HEA coatings have equiaxed and columnar grains with A2 + B2 + σ structure.•The mechanical properties deteriorate as cladding specific heat input increases.•The corrosion types of coatings are pitting corrosion and intergranular corrosion.