ELECTRON MICROSCOPE OBSERVATIONS ON THE PRECIPITATION OF ZIRCONIUM HYDRIDE IN ZIRCONIUM
A study has been made of the precipitation of zirconium hydride in zirconium at hydrogen concentrations in the range 100 to 1000 ppm using the transmission electron microscopy technique. In rapidly cooled or quenched specimens the precipitates appear needle-like with axes lying along (1120) directions and are probably platelets parallel to {1010} planes of the matrix. In slowly cooled specimens the precipitates appear comparatively large in two dimensions. Electron and x-ray diffraction experiments show that all precipitates have a face centered tetragonal structure. Identical orientation relations also appear to hold for all precipitates. The needle-like precipitates grow rapidly along their (1120) type axes apparently remaining coherent; growth in the direction normal to their axes is accompanied by the formation of dislocations and the precipitates become incoherent on the appropriate faces. Beam heating experiments show that nucleation of the hydride does not necessarily require the presence of dislocations but that preferential precipitation will occur on them and on grain boundaries when present. (auth)
- Research Organization:
- Central Electricity Generating Board, Berkeley, Glos., Eng.
- NSA Number:
- NSA-17-018788
- OSTI ID:
- 4739755
- Journal Information:
- Acta Met., Vol. Vol: 11; Other Information: Orig. Receipt Date: 31-DEC-63
- Country of Publication:
- Country unknown/Code not available
- Language:
- English
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Related Subjects
CONFIGURATION
COOLING
CRYSTALLIZATION
CRYSTALS
DEFECTS
DIFFRACTION
DISLOCATIONS
DISTRIBUTION
ELECTRON BEAMS
ELECTRON MICROSCOPY
EXPANSION
GRAIN BOUNDARIES
HEATING
NUCLEATE BOILING
PRECIPITATION
QUENCHING
SURFACES
VELOCITY
X RADIATION
ZIRCONIUM
ZIRCONIUM HYDRIDES