| YAO Yu-hong,LIANG Xiao-yu,JIN Yao-hua,WANG Zheng-pin,NANJO Hiroshi.Effect of B Addition on Microstructure and High Temperature Oxidation Resistance of AlMo0.5NbTa0.5TiZr Refractory High-entropy Alloys[J],49(2):235-242 |
| Effect of B Addition on Microstructure and High Temperature Oxidation Resistance of AlMo0.5NbTa0.5TiZr Refractory High-entropy Alloys |
| Received:August 14, 2019 Revised:February 20, 2020 |
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| DOI：10.16490/j.cnki.issn.1001-3660.2020.02.029 |
| KeyWord:refractory high-entropy alloys microstructure oxidation resistance oxidation film Nb4Ta2O15 AlNbO4 |
| Author | Institution |
| YAO Yu-hong |
1.Shaanxi Provincial Key Laboratory of Photoelectric Functional Materials and Devices, Xi'an Technological University, Xi'an , China |
| LIANG Xiao-yu |
1.Shaanxi Provincial Key Laboratory of Photoelectric Functional Materials and Devices, Xi'an Technological University, Xi'an , China |
| JIN Yao-hua |
1.Shaanxi Provincial Key Laboratory of Photoelectric Functional Materials and Devices, Xi'an Technological University, Xi'an , China |
| WANG Zheng-pin |
1.Shaanxi Provincial Key Laboratory of Photoelectric Functional Materials and Devices, Xi'an Technological University, Xi'an , China |
| NANJO Hiroshi |
2.National Institute of Advanced Industrial Science and Technology AIST Tohoku Center, Sendai 983-8551, Japan |
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| Abstract: |
| The work aims to improve the high temperature oxidation resistance of AlMo0.5NbTa0.5TiZr refractory high- entropy alloys, AlMo0.5NbTa0.5TiZrBx (x=0, 0.02, 0.06) refractory high-entropy alloys were prepared by a non-consumable vacuum arc melting technology and the effects of B on the microstructure and high temperature oxidation resistance were investigated by a series of high temperature oxidation experiments, XRD, SEM-BSE and EDS. The results show that the microstructures of as-cast AlMo0.5NbTa0.5TiZr alloy has the characteristic of dendritic morphology with Al-Ti-Zr rich BCC1 phase in black interdendritic zone, Mo-Nb-Ta rich BCC2 phase in bright dendritic zone and Al-Zr rich phase between the dendritic zone and the interdendritic zone. The addition of trace amounts of B (x=0.02 and x=0.06) does not change the phase composition but refine the dendritic structure of the alloy. For the addition of B with x=0.06, the exothermic peak value decreases from 0.95 W/g to 0.05 W/g, whereas the peak temperature for oxidation reaction increases from 880 ℃ to 1020 ℃. B addition can alleviate the exfoliation of the oxidation film formed in the process of the short-term oxidation and prevent the disastrous oxidation of AlMo0.5NbTa0.5TiZr alloy during long-term oxidation. Oxidized at 800 ℃ for 50 h, the complex protective oxidation layer with Nb4Ta2O15 and AlNbO4 are formed on the surface of AlMo0.5NbTa0.5TiZrB0.06. Therefore, B addition can not only obviously reduces the oxidation weight gain rate but also greatly enhance the oxidation resistance of the alloy oxidized at both 800 ℃ for 3 h and 800 ℃ for 50 h. |
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