Dislocation mechanisms, diffusional processes and creep behavior in NbC/sub chi/

Journal Article · Wed Feb 01 00:00:00 EST 1989 · Acta Metallurgica; (USA)

DOI:https://doi.org/10.1016/0001-6160(89)90226-5· OSTI ID:5650800

Chevacharoenkul, S; Davis, R F ^[1]

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1. North Carolina Univ., Chapel Hill, NC (USA)

A brittle-ductile transition occurs around 1373 {Kappa} in NbC/sub chi/ as a result of the increase in the character of the bonding with increasing temperature. Steady-state creep in NbC/sub chi/ between 1373 and 1573 {Kappa} occurs by dislocation glide to form equiaxed cell structures; it is controlled by the unlocking of dislocation interactions within the cell walls. Between 1573 and 1873 {Kappa}, the kinetic data indicate a transition from dislocation glide to dislocation climb as the rate controlling creep process. Above 1873 {Kappa}, subboundary formation, and polygonization confirms that dislocation glide and climb are occurring during creep. The activation energy values for creep in this temperature range are consistent with niobium lattice diffusion as the rate controlling mechanism.

• OSTI ID: 5650800
• Journal Information: Acta Metallurgica; (USA), Vol. 37:2; ISSN 0001-6160
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
NIOBIUM CARBIDES
BRITTLE-DUCTILE TRANSITIONS
ACTIVATION ENERGY
BONDING
CREEP
DIFFUSION
DISLOCATION PINNING
TEMPERATURE DEPENDENCE
CARBIDES
CARBON COMPOUNDS
ENERGY
FABRICATION
JOINING
MECHANICAL PROPERTIES
NIOBIUM COMPOUNDS
REFRACTORY METAL COMPOUNDS
TRANSITION ELEMENT COMPOUNDS
360203* - Ceramics
Cermets
& Refractories- Mechanical Properties
360202 - Ceramics
Cermets
& Refractories- Structure & Phase Studies