Effect of Al/Cu Ratio on Microstructure and High-Temperature Oxidation Resistance of Al<sub>x</sub>CoCrCu<sub>y</sub>FeNi High-Entropy Alloy Coatings
To improve high-temperature oxidation resistance for Ti6Al4V alloy, Al<sub>x</sub>CoCrCu<sub>y</sub>FeNi (x = 0, 0.3, 0.5, 0.7, 1.0; y = 1.0, 0.7, 0.5, 0.3, 0, x + y = 1.0) high-entropy alloy (HEA) coatings were prepared on the Ti6Al4V alloy substrate by a laser cladding tech...
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| Main Authors: | , , , , , , , , |
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| Format: | Article |
| Language: | English |
| Published: |
MDPI AG
2025-01-01
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| Series: | Journal of Manufacturing and Materials Processing |
| Subjects: | |
| Online Access: | https://www.mdpi.com/2504-4494/9/1/13 |
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| Summary: | To improve high-temperature oxidation resistance for Ti6Al4V alloy, Al<sub>x</sub>CoCrCu<sub>y</sub>FeNi (x = 0, 0.3, 0.5, 0.7, 1.0; y = 1.0, 0.7, 0.5, 0.3, 0, x + y = 1.0) high-entropy alloy (HEA) coatings were prepared on the Ti6Al4V alloy substrate by a laser cladding technique. The results show that the coatings were mainly composed of FCC, BCC, and Ti-rich phases. Severe segregation of the Cu element occurred in the CoCrCuFeNi HEA coatings as a Cu-rich phase (FCC2). The Cu-rich phases decreased with a decreasing Cu content and completely disappeared until the Al content reached 1.0. The microhardnesses of the Cu<sub>1.0</sub>, Cu<sub>0.7</sub>Al<sub>0.3</sub>, Cu<sub>0.5</sub>Al<sub>0.5</sub>, Cu<sub>0.3</sub>Al<sub>0.7</sub>, and Al<sub>1.0</sub> HEA coatings were 2.01, 2.06, 2.08, 2.09, and 2.11 times that of the substrate, and compared with those of a Ti6Al4V alloy substrate, the oxidation rates of the HEA coatings decreased by 55%, 51%, 47%, 42%, and 35%, respectively. The surface oxides of the five coatings were mainly composed of CuO, TiO<sub>2</sub>, Fe<sub>3</sub>O<sub>4</sub>, Cr<sub>2</sub>O<sub>3</sub>, and Al<sub>2</sub>O<sub>3</sub>. The increase in the Al content promoted the generation of Al<sub>2</sub>O<sub>3</sub> film and Cr<sub>2</sub>O<sub>3</sub> on the surfaces of the coatings, which significantly improved the high-temperature antioxidant performance of the high-entropy alloy coatings for 50 h at 800 °C. When x = 1.0, the coating showed the best high-temperature antioxidant performance. |
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| ISSN: | 2504-4494 |