Abstract
Significantly enhanced mass-transport related effects such as sintering and grain-growth have been reported at large distances from stoichiometry in titanium carbide. The diffusivity of both C and Ti in this compound are coupled and the rate of mass transport is determined by the lower mobility of Ti. Quantitative grain-growth measurements of samples with different C/Ti ratio confirmed the large mass transport effects at low carbon content. A model based on the statistical distribution of vacant carbon sites in the immediate environment of the Ti atoms was put forward in order to account for the greatly enhanced diffusivity of Ti at low values of the C/Ti ratio. The dominant determining factor at that ratio is the reduced enthalpy of formation of Ti vacancies in the absence of nearest neighbor carbon atoms. The composition dependence of the observed grain-growth is in reasonable agreement with the predictions of the model.
Original language | English |
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Pages (from-to) | 27-36 |
Number of pages | 10 |
Journal | Poroshkovaya Metallurgiya |
Issue number | 9-10 |
State | Published - 1 Dec 2003 |
Keywords
- Carbides TiC
- Diffusion
- Grain-growth
ASJC Scopus subject areas
- Mechanical Engineering
- Metals and Alloys