The critical role of Si doping in enhancing the stability of M6C carbides
| Autor: | Long Yan, Jiasheng Dong, Li Jiang, Ai-Ming Li, Ruobing Xie, Zhijun Li, Xingtai Zhou, Tsun-Kong Sham, Xiang-Xi Ye, Zhiqiang Wang, Cun Yu |
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| Rok vydání: | 2017 |
| Předmět: |
Materials science
Silicon Mechanical Engineering Doping Metals and Alloys chemistry.chemical_element 02 engineering and technology Crystal structure Electronic structure 010402 general chemistry 021001 nanoscience & nanotechnology 01 natural sciences 0104 chemical sciences Carbide Superalloy Crystallography chemistry Mechanics of Materials X-ray crystallography Materials Chemistry Absorption (chemistry) 0210 nano-technology |
| Zdroj: | Journal of Alloys and Compounds. 728:917-926 |
| ISSN: | 0925-8388 |
| Popis: | M6C carbides are one of the most common second phases in high speed steels and superalloys, and also an alternative catalytic materials for energy applications. Although the influences of Si doping on the stability of M6C carbides have been frequently observed in different alloys, the atomic-scale mechanism of which remains poorly understood. Here we obtain the Ni3Mo3C-type M6C carbides in GH3535 alloys and evaluate the dependence of their structure and composition on Si contents. Combining high-energy synchrotron X-ray diffraction and first-principle calculations, Si atoms are found to preferentially occupy Ni (16d) sites in Ni3Mo3C structure. The electronic structures and Si K-edge x-ray absorption near edge structures demonstrate the band hybridization and charge transfer between Si atoms and the nearest-neighbor Ni (32e) and Mo (48f) atoms in Si-doped Ni3Mo3C structures, which is responsible for the stability of M6C carbides. |
| Databáze: | OpenAIRE |
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