Influence of Heat Treatment in /cap beta/ and $gamma$ Phases on the Microscopic Structure of Uranium; INFLUENCE DES TRAITEMENTS THERMIQUES EN PHASES /cap beta/ ET $gamma$ SUR LA STRUCTURE MICROGRAPHIQUE DE L'URANIUM

Thesis/Dissertation · Wed Jul 01 04:00:00 EDT 1959

OSTI ID:4200317

Robillard, A

A new method of microscopic examination of uranium is described. Electrolytic polishing and etching are carried out in an acetic acid-chromic acid bath. Atmospheric or anodic oxidation of the polished surface produces films which follow exactly changes in the structure of the underlying metal. This method is very sensitive to small variations of orientation in polygonized crystals. Using this method of examination of uranium, it was found that annealing U in the {gamma} phase followed by a cooling at a rate dependent of the annealing temperature, causes the formation of substructures different from those due to the polygonization of {alpha}-U. The substructures are indicated by the concentration of impurities on the dislocations induced by the stresses accompanying the allotropic transformation {gamma} {yields} {beta}. Similar treatment of the U-1.4% Cr alloy in which the {beta} phase is stabilized at room temperature, confirms this explanation. In addition to the polygonization substructures, sharp discontinuities can be observed in the network of sub- boundaries as a fine white edging. The comparison of these with the structure revealed by thermal etching in vacuum suggest that there are traces of the grain boundaries of the {gamma} phase. The method of etching followed by oxidation shows a haloed phase identified as UH{sub 3}. The conditions of appearance and disappearance of this phase are studied. The sensitivity of this method of detecting the last traces of H in U is very high. The dependence of the hydrogen content on the tensile properties of uranium metal was also studied. (author)

• Research Organization: France. Commissariat a l'Energie Atomique, Paris
• NSA Number: NSA-14-007762
• OSTI ID: 4200317
• Report Number(s): CEA-1057
• Country of Publication: France
• Language: French

Related Subjects

ACETIC ACID
ALLOTROPY
ANNEALING
ANODES
CHROMIUM ALLOYS
CHROMIUM OXIDES
CLEANING
CONFIGURATION
COOLING
CRYSTALS
DEFECTS
DISLOCATIONS
ELECTROCHEMISTRY
ETCHING
FILMS
GRAIN BOUNDARIES
HEAT TREATMENTS
HYDROGEN
IMPURITIES
LATTICES
METALS, CERAMICS, AND MATERIALS
MICROSCOPY
OXIDATION
PHASE DIAGRAMS
QUANTITY RATIO
SENSITIVITY
SOLUTIONS
STABILITY
STRESSES
SURFACES
TEMPERATURE
TENSILE PROPERTIES
TRACE AMOUNTS
URANIUM
URANIUM ALLOYS
URANIUM HYDRIDES
URANIUM- BETA
URANIUM-GAMMA
VACUUM
VARIATIONS