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Vol.40, No.11, 1156 ~ 1165, 2002
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| Title |
| Microstructure, Wear Resistance, and Fracture Properties of (TiC, SiC)/Ti-6Al-4V Surface Composites Fabricated by High-Energy Electron Beam Irradiation (Part 1. Formation Process of Microstructure) |
| 오준철 Jun Cheol Oh , 윤은섭 Eun Sub Yun , 이성학 Sung Hak Lee |
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| Abstract |
| The present study is concearned with microstructural analysis of (TiC, SiC)/Ti-6Al-4V surfaces composites fabricated by high-energy electron beam irradiation. The mixtures of TiC, SiC, Ti+SiC, and TiC+SiC powders and CaF_2 flux were evenly deposited on a Ti-6Al-4V substrate, and then electron beam was irradiated on these mixtures using an electron beam accelerator. In the specimens processed with flux addition, the surface-alloyed layers of 1.2∼2.1 ㎜ in thickness were homogeneously formed without defects, and contained a large amount (30∼66 vol.%) of precipitates such as TiC and Ti_5Si_3 in the martensitic matrix. Upon electron beam irradiation, (TiC, SiC)/flux powder mixtures and part of the substrate were melted to form a molten metal containing Ti, Si, and C. Here, C and Si atoms interacted with Ti atoms to form TiC and Ti_5Si_3, respectively, and the matrix was composed of martensite because of fast cooling during solidification. Microstructural modifications including melting, solidification, precipitation, and phase transformation processes could be explained well from a Ti-Si-C ternary phase diagram. |
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| Key Words |
| Surface composite, Electron beam irradiation, Ti-6Al-4V, TiC, SiC, Flux, Microstructure |
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