METALLOGRAPHIC STUDY OF STRUCTURAL STRINGERS IN ZIRCALOY-2

Journal Article · Mon May 01 04:00:00 EDT 1961 · J. Nuclear Materials

DOI:https://doi.org/10.1016/0022-3115(61)90145-3· OSTI ID:4003083

Jacquet, P A

The new technique of localized electrolytic polishing was applied to the study of the stringers in Zircaloy-2. These defects were detected exclusively in forged billets and rolled sheets made from ingots which were cast from alloy melted in consumable arc furnaces in an argon atmosphere. Products made from ingots produced by vacuum melting do not contain stringers. The variation of the micrographic appearance with the polishing conditions (primarily the nature of the electrolyte), and the influence of anodic oxidation tend to show that structural stringers are not a form of porosity inherited from the ingot. They are associated with chemical heterogeneities (an unidentified intermetallic constituent, oxides) resulting from the thermal conditions of melting and from impurities in the atmosphere. A confusion between physical discontinuities and correspondingly shaped features of the microstructure can arise from the corrosive action of the etching reagents on mechanically polished surfaces. Comparison of the structure of billets and sheets, x-ray analysis, and the results of observations by others permit an interpretation of the effects of hot rolling. The appearance of macroscopic defects results from the inflation, by oxygen, of filaments at the surface. Moreover, the insolubility of the relevant oxides accounts for the known fact that a prolonged treatment at high temperature can eliminate the concentration gradients responsible for so-called corrosion- stringers, while leaving unaffected those filaments which are formed by oxide segregation. (auth)

• Research Organization: Centre d'Etudes Nucleaires, Saclay, France
• NSA Number: NSA-15-026579
• OSTI ID: 4003083
• Journal Information: J. Nuclear Materials, Journal Name: J. Nuclear Materials Vol. Vol: 4
• Country of Publication: Country unknown/Code not available
• Language: French

Related Subjects

ANODES
ARGON
CASTING
CLEANING
CORROSION
DEFECTS
DISTRIBUTION
ELECTROLYTES
ETCHING
FORGING
FURNACES
HEAT TREATMENTS
HIGH TEMPERATURE
HOT WORKING
IMPURITIES
INTERMETALLIC COMPOUNDS
MELTING
METALLOGRAPHY
METALS, CERAMICS, AND OTHER MATERIALS
OXIDATION
OXIDES
OXYGEN
POROSITY
ROLLING
SEGREGATION
SHEETS
SURFACES
VACUUM
WIRES
X RADIATION
ZIRCALOY