| WANG Linqing,PU Chunlin,ZHANG Yan,WANG Junjun.Effect of Al Content on High-temperature Oxidation Resistance of TiZrNbMoAlx Refractory High Entropy Alloy Thin Films[J],54(1):53-61, 73 |
| Effect of Al Content on High-temperature Oxidation Resistance of TiZrNbMoAlx Refractory High Entropy Alloy Thin Films |
| Received:September 18, 2024 Revised:December 31, 2024 |
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| DOI：10.16490/j.cnki.issn.1001-3660.2025.01.005 |
| KeyWord:refractory high entropy alloy thin film high temperature oxidation resistance Al content phase composition microstructure |
| Author | Institution |
| WANG Linqing |
School of Science,Chongqing , China |
| PU Chunlin |
School of Science,Chongqing , China |
| ZHANG Yan |
School of Materials Science and Engineering, Chongqing University of Technology, Chongqing , China |
| WANG Junjun |
School of Materials Science and Engineering, Chongqing University of Technology, Chongqing , China |
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| Abstract: |
| Refractory high-entropy alloys (RHEAs), which exhibit excellent mechanical properties at high temperature, are being developed for potential applications in high-temperature environments. However, their poor high-temperature oxidation resistance significantly restricts their practical application. This work aims to investigate the oxidation resistance behavior of TiZrNbMoAlx RHEAs films with different Al contents, and provide theoretical supports for improving the oxidation resistance of TiZrNbMoAlx RHEAs films. In this study, TiZrNbMoAlx RHEAs films were prepared using a magnetron co-sputtering system with a spliced target (ϕ76.2 mm×5 mm) composed of 90° fan-shaped Ti, Zr, Nb and Mo (99.95% purity), and an Al target (ϕ76.2 mm×5 mm, 99.95% purity) as the sputtering targets. TiZrNbMoAlx RHEAs films with different Al contents (0at.%, 14at.%, 18at.%, 24at.% and 28at.%) were obtained by adjusting the sputtering power of the Al target. The as-deposited TiZrNbMoAlx RHEAs films were subjected to oxidation tests at 600 ℃ in air. The phase composition and microstructure of the films before and after oxidation were analyzed by field emission scanning electron microscopy (FESEM), energy dispersive spectroscopy (EDS), X-ray photoelectron spectroscopy (XPS) and X-ray Diffraction (XRD). The oxidation resistance of TiZrNbMoAlx RHEAs films with different Al contents was compared, and the oxidation mechanisms of the films were analyzed. It was found that the microstructure and high-temperature oxidation resistance of the films were strongly dependent on the Al content. The TiZrNbMoAlx RHEAs films without Al content presented a (110) preferred orientation BCC single-phase solid solution structure. The TiZrNbMoAlx RHEAs films with low Al contents (14at.%-24at.%) exhibited an amorphous phase structure. When the Al content was high (28at.%), an AlZr3 secondary phases were found in the films. After oxidation at 600 ℃, in the absence of Al content, cellular protrusions appeared on the film surface, accompanied by fissures. Notably, some protrusions detached easily when manipulated with tweezers. Simultaneously, the film thickness increased from an initial 1.20 μm to 2.20 μm, representing an accelerated thickness growth rate of 83%, ultimately leading to complete oxidation of the film. The introduction of Al effectively improved the oxidation resistance characteristics of the TiZrNbMoAlx RHEAs films, attributed to the presence of an oxide layer containing Al2O3 on the film surface. The higher the Al content, the denser the oxide layer containing Al2O3, and the better the oxidation resistance of the film. When the Al content increased from 14at.% to 24at.%, the thickness growth rate decreased from 83% to 28%. However, excessive Al content (28at.%) led to stress concentration, resulting in cracks that worsened the high-temperature oxidation resistance of the films. In conclusion, Al content has a significant influence on the high-temperature oxidation resistance properties of TiZrNbMoAlx RHEAs films. Appropriate Al content can improve the oxidation resistance properties of TiZrNbMoAlx RHEAs films. |
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