| Abstract |
| This study is concerned with the improvement of abrasive and sliding wear properties of (TiC, SiC)/Ti-6Al-4V surface composites fabricated by high-energy electron beam irradiation. The mixtures of TiC, SiC, SiC+Ti, or SiC+TiC powders and CaF_2 flux were deposited on a Ti-6Al-4V substrate, and then electron beam was irradiated on these mixtures. The surface composite layers of 1.2∼2.1 ㎜ in thickness were homogeneously formed without defects, and contained a large amount (30∼66 vol.%) of hard phases such as TiC and Ti_5Si_3 in the martensitic matrix. This microstructural modification including the formation of hard phases in the surface composite layer improved hardness and abrasive wear resistance. Particularly in the surface composite fabricated with TiC+SiC powders, the abrasive wear resistance was greatly enhanced by 25 times higher than that of the Ti alloy substrate because of the formation of 66 vol.% of TiC and Ti_5Si_3 in the hardened martensitic matrix. During the sliding wear process, hard and coarse TiC and Ti_5Si_3 were fallen off from the matrix, and their wear debris worked as abrasive particles, thereby reducing the sliding wear resistance. On the other hand, needle-shaped Ti_5Si_3 decelerated the sliding wear because their wear debris were fine and worked as solid lubricants instead of abrasive particles. These findings indicated that high-energy electron beam irradiation was economical and useful for the development of Ti-base surface composites with improved abrasive and sliding wear properties, although the abrasive and sliding wear data should be interpreted by different wear mechanisms. |
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| Key Words |
| Surface composite, Electron beam irradiation, Ti-6A1-4V, TiC, SiC, Flux, Abrasive wear, Sliding wear, Hardness |
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