Effect of Ti Content on the Microstructure and Corrosion Resistance of CoCrFeNiTi<sub>x</sub> High Entropy Alloys Prepared by Laser Cladding
In this paper, CoCrFeNiTi<sub>x</sub> high entropy alloy (HEA) coatings were prepared on the surface of Q235 steel by laser cladding. The microstructure, microhardness, and corrosion resistance of the coatings were studied. The mechanism of their corrosion resistance was elucidated exper...
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MDPI AG
2020-05-01
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| Online Access: | https://www.mdpi.com/1996-1944/13/10/2209 |
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| author | Xinyang Wang Qian Liu Yanbin Huang Lu Xie Quan Xu Tianxiang Zhao |
| author_facet | Xinyang Wang Qian Liu Yanbin Huang Lu Xie Quan Xu Tianxiang Zhao |
| author_sort | Xinyang Wang |
| collection | DOAJ |
| description | In this paper, CoCrFeNiTi<sub>x</sub> high entropy alloy (HEA) coatings were prepared on the surface of Q235 steel by laser cladding. The microstructure, microhardness, and corrosion resistance of the coatings were studied. The mechanism of their corrosion resistance was elucidated experimentally and by first-principles calculations. The results show that CoCrFeNiTi<sub>0.1</sub> adopts a face-centered cubic (FCC) phase, CoCrFeNiTi<sub>0.3</sub> exhibits an FCC phase and a tetragonal FeCr phase, and CoCrFeNiTi<sub>0.5</sub> adopts an FCC phase, a tetragonal FeCr phase, and a rhombohedral NiTi phase. The FCC phase, tetragonal FeCr phase, rhombohedral NiTi phase, and hexagonal CoTi phase are all observed in the CoCrFeNiTi<sub>0.7</sub> HEA. The alloys assume the dendritic structure that is typical of HEAs. Ni and Ti are enriched in the interdendritic regions, whereas Cr and Fe are enriched in the dendrites. With increasing Ti content, the hardness of the cladding layers also increases due to the combined effects of lattice distortion and dispersion strengthening. When exposed to a 3.5 wt.% NaCl solution, pitting corrosion is the main form of corrosion on the CoCrFeNiTi<sub>x</sub> HEA surfaces. The corrosion current densities of CoCrFeNiTi<sub>x</sub> HEAs are much lower than those of other HEAs. As the Ti content increases, the corrosion resistance is improved. Through X-ray photoelectron spectroscopy (XPS) and first-principles calculations, the origin of the higher corrosion resistance of the coatings is connected to the presence of a dense passivation film. In summary, the corrosion resistance and mechanical properties of CoCrFeNiTi<sub>0.5</sub> alloy are much better than the other three groups, which promotes the development of HEA systems with high value for industrial application. |
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| spelling | doaj.art-36be186f206046b68ff95d42bc45d39a2023-11-20T00:08:55ZengMDPI AGMaterials1996-19442020-05-011310220910.3390/ma13102209Effect of Ti Content on the Microstructure and Corrosion Resistance of CoCrFeNiTi<sub>x</sub> High Entropy Alloys Prepared by Laser CladdingXinyang Wang0Qian Liu1Yanbin Huang2Lu Xie3Quan Xu4Tianxiang Zhao5Equipment Support and Remanufacturing Department, Army Academy of Armored Forces, Beijing 100072, ChinaEquipment Support and Remanufacturing Department, Army Academy of Armored Forces, Beijing 100072, ChinaEquipment Support and Remanufacturing Department, Army Academy of Armored Forces, Beijing 100072, ChinaSchool of Mechanical Engineering, University of Science and Technology Beijing, Beijing 100083, ChinaChina Satellite Maritime Measurement and Control Department, Jiangyin 214431, ChinaChina Satellite Maritime Measurement and Control Department, Jiangyin 214431, ChinaIn this paper, CoCrFeNiTi<sub>x</sub> high entropy alloy (HEA) coatings were prepared on the surface of Q235 steel by laser cladding. The microstructure, microhardness, and corrosion resistance of the coatings were studied. The mechanism of their corrosion resistance was elucidated experimentally and by first-principles calculations. The results show that CoCrFeNiTi<sub>0.1</sub> adopts a face-centered cubic (FCC) phase, CoCrFeNiTi<sub>0.3</sub> exhibits an FCC phase and a tetragonal FeCr phase, and CoCrFeNiTi<sub>0.5</sub> adopts an FCC phase, a tetragonal FeCr phase, and a rhombohedral NiTi phase. The FCC phase, tetragonal FeCr phase, rhombohedral NiTi phase, and hexagonal CoTi phase are all observed in the CoCrFeNiTi<sub>0.7</sub> HEA. The alloys assume the dendritic structure that is typical of HEAs. Ni and Ti are enriched in the interdendritic regions, whereas Cr and Fe are enriched in the dendrites. With increasing Ti content, the hardness of the cladding layers also increases due to the combined effects of lattice distortion and dispersion strengthening. When exposed to a 3.5 wt.% NaCl solution, pitting corrosion is the main form of corrosion on the CoCrFeNiTi<sub>x</sub> HEA surfaces. The corrosion current densities of CoCrFeNiTi<sub>x</sub> HEAs are much lower than those of other HEAs. As the Ti content increases, the corrosion resistance is improved. Through X-ray photoelectron spectroscopy (XPS) and first-principles calculations, the origin of the higher corrosion resistance of the coatings is connected to the presence of a dense passivation film. In summary, the corrosion resistance and mechanical properties of CoCrFeNiTi<sub>0.5</sub> alloy are much better than the other three groups, which promotes the development of HEA systems with high value for industrial application.https://www.mdpi.com/1996-1944/13/10/2209high entropy alloy coatinglaser claddingCoCrFeNiTifirst-principles calculationcorrosion resistance |
| spellingShingle | Xinyang Wang Qian Liu Yanbin Huang Lu Xie Quan Xu Tianxiang Zhao Effect of Ti Content on the Microstructure and Corrosion Resistance of CoCrFeNiTi<sub>x</sub> High Entropy Alloys Prepared by Laser Cladding Materials high entropy alloy coating laser cladding CoCrFeNiTi first-principles calculation corrosion resistance |
| title | Effect of Ti Content on the Microstructure and Corrosion Resistance of CoCrFeNiTi<sub>x</sub> High Entropy Alloys Prepared by Laser Cladding |
| title_full | Effect of Ti Content on the Microstructure and Corrosion Resistance of CoCrFeNiTi<sub>x</sub> High Entropy Alloys Prepared by Laser Cladding |
| title_fullStr | Effect of Ti Content on the Microstructure and Corrosion Resistance of CoCrFeNiTi<sub>x</sub> High Entropy Alloys Prepared by Laser Cladding |
| title_full_unstemmed | Effect of Ti Content on the Microstructure and Corrosion Resistance of CoCrFeNiTi<sub>x</sub> High Entropy Alloys Prepared by Laser Cladding |
| title_short | Effect of Ti Content on the Microstructure and Corrosion Resistance of CoCrFeNiTi<sub>x</sub> High Entropy Alloys Prepared by Laser Cladding |
| title_sort | effect of ti content on the microstructure and corrosion resistance of cocrfeniti sub x sub high entropy alloys prepared by laser cladding |
| topic | high entropy alloy coating laser cladding CoCrFeNiTi first-principles calculation corrosion resistance |
| url | https://www.mdpi.com/1996-1944/13/10/2209 |
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