Insight into the high-temperature tribological mechanism of VAlTiCrW high entropy alloy film: AlV3O9 from tribochemistry
Abstract High-entropy alloys have made significant progress in high mechanical properties, wear resistance, and corrosion resistance properties. Excellent tribological properties, especially high-temperature lubrication, have become another sought performance. In this work, VAlTiCrW high-entropy all...
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| Main Authors: | , , , |
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| Format: | Article |
| Language: | English |
| Published: |
Tsinghua University Press
2022-09-01
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| Series: | Friction |
| Subjects: | |
| Online Access: | https://doi.org/10.1007/s40544-022-0640-7 |
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| Summary: | Abstract High-entropy alloys have made significant progress in high mechanical properties, wear resistance, and corrosion resistance properties. Excellent tribological properties, especially high-temperature lubrication, have become another sought performance. In this work, VAlTiCrW high-entropy alloy film with body-centered cubic (BCC) structure was prepared on superalloy substrate by magnetron sputtering. It is found that the VAlTiCrW film shows very low friction coefficient of 0.15 and a low wear rate of 10−5 orders of magnitude at 800 °C. After 800 °C oxidation, the film can still obtain a friction coefficient of no more than 0.2 at 700 °C. XRD and TEM revealed the formation of ternary oxide AlV3O9 with preferred orientation of (002) crystal plane with large spacing of 0.71 nm on the wear surface of the film, a high-temperature lubricating phase that has not been reported, realizes the low friction coefficient. This AlV3O9 can be formed by tribochemical reaction under the thermal-mechanical action at 700 °C, but pre-oxidation at 800 °C is the prerequisite in order to form the precursors of V-rich and Al-rich oxide layer. |
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| ISSN: | 2223-7690 2223-7704 |