Inelastic deformation and microstructural analysis of transition metal carbides
Thesis/Dissertation
·
OSTI ID:6086177
The densification behavior of (Ti,V)C alloys was studied by hot pressing experiments. The effects of temperature and composition on final porosity, grain size, and phases present were determined. The diffusion coefficients determined from densification data agree well with the grain boundary diffusion coefficient of carbon. This observation, combined with microstructural evidence, indicates that the final stage of densification is controlled by grain boundary diffusion of carbon and/or metal. The enhanced densification and grain growth in VC-rich samples are attributed to the presence of second phase material along the grain boundaries. The rapid interdiffusion of Ti and N in (Ti,V)C to form a single phase, raises the possibility of faster diffusion along the migrating boundaries in contrast to the stationary boundaries. Load relaxation experiments were performed at 1200/sup 0/ to 1600/sup 0/C on fully dense, single phase, polycrystalline (Ti,V)C alloys, prepared by hot-pressing. The analysis of logsigma - log(epsilon) data along with the evaluation of strain rate sensitivity and the grain size dependence indicates that the high temperature plastic deformation of these carbides occurs by grain boundary diffusion, which is in accordance with hot-pressing results. A sharp decrease in the strength of (Ti,V)C alloys with the addition of VC is associated with the softening and/or melting of the second phase accumulated along the grain boundaries.
- Research Organization:
- Cornell Univ., Ithaca, NY (USA)
- OSTI ID:
- 6086177
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
36 MATERIALS SCIENCE
360201* -- Ceramics
Cermets
& Refractories-- Preparation & Fabrication
360202 -- Ceramics
Cermets
& Refractories-- Structure & Phase Studies
CARBIDES
CARBON COMPOUNDS
CRYSTAL STRUCTURE
DEFORMATION
DENSITY
DIFFUSION
FABRICATION
GRAIN BOUNDARIES
HOT PRESSING
MATERIALS WORKING
MICROSTRUCTURE
PHASE STUDIES
PHYSICAL PROPERTIES
PRESSING
QUANTITY RATIO
TEMPERATURE EFFECTS
TITANIUM CARBIDES
TITANIUM COMPOUNDS
TRANSITION ELEMENT COMPOUNDS
VANADIUM CARBIDES
VANADIUM COMPOUNDS
VERY HIGH TEMPERATURE
360201* -- Ceramics
Cermets
& Refractories-- Preparation & Fabrication
360202 -- Ceramics
Cermets
& Refractories-- Structure & Phase Studies
CARBIDES
CARBON COMPOUNDS
CRYSTAL STRUCTURE
DEFORMATION
DENSITY
DIFFUSION
FABRICATION
GRAIN BOUNDARIES
HOT PRESSING
MATERIALS WORKING
MICROSTRUCTURE
PHASE STUDIES
PHYSICAL PROPERTIES
PRESSING
QUANTITY RATIO
TEMPERATURE EFFECTS
TITANIUM CARBIDES
TITANIUM COMPOUNDS
TRANSITION ELEMENT COMPOUNDS
VANADIUM CARBIDES
VANADIUM COMPOUNDS
VERY HIGH TEMPERATURE