Published June 1980 | Version v1
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Correlations between microstructure and creep rupture ductility evolution of ZCND 17/13 stainless between 550 deg C and 700 deg C

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Description

Creep ductility evolution of ZCND 17/13 stainless steel used in the 'Phenix' boiler, has been studied between 550 deg C and 700 deg C in the strong stress field and analysed by microstructure examinations. In all the (T, sigma) field concerned, grain boundary sliding, revealed by cracks at triple boundary jonctions, appeared to play a leading part in rupture. Taking into account grain boundary precipitation stability which restricts the grain boundary sliding, ductility behavior seems to depend on the strain strengthening matrix evolution which occurs during creep when experimental conditions let or no the precipitation of various phases rich in hardening elements (Mo-C). This softening noticed at temperatures equals or higher than 600 deg C delay the formation of cracks at grain boundaries and results in high values of the rupture strain. At 500 deg C the matrix strongly strengthened by hardening elements and by the strain due to initial loading induces intergranular ruptures for low strain creep: the advent of matrix precipitation after 104h of creep allows to forecast a futur increasing of the ductility with the creep rupture time

Availability note (English)

MF available from INIS under the Report Number.

Abstract (French)

Les evolutions de la ductilite a rupture en fluage de la nuance d'acier ZCND 17/13 utilisee pour la fabrication de la cuve de 'Phenix' ont ete etudiees entre 550 deg C et 700 deg C dans le domaine des fortes contraintes et analysees a l'aide d'examens de microstructure et d'essais mecaniques instantanes. Dans tout le domaine (T, sigma) concerne, le glissement intergranulaire, mis en evidence par la presence de decohesions intergranulaires aux points triples, apparait jouer un role preponderant dans la rupture. Compte tenu de la relative stabilite des caracteristiques dimensionnelles de la precipitation intergranulaire qui limite d'une maniere constante le glissement aux joints de grains, le comportement en ductilite de l'alliage concerne semble lie a l'evolution de la resistance a la deformation de la matrice qui se produit au cours du fluage selon que les conditions experimentales permettent ou non la precipitation des diverses phases riches en elements durcissants (Mo-C). Cet adoucissement, constate aux temperatures superieures ou egales a 600 deg C retarde la germination des decohesions aux points triples et provoque ainsi de fortes valeurs d'allongement a rupture. A 550 deg C la matrice, efficacement renforcee par les elements durcissants et par un important ecrouissage de mise en charge, induit des les faibles deformations des ruptures intergranulaires: l'apparition d'une precipitation intergranulaire apres 104h de fluage, laisse cependant prevoir une augmentaton prochaine de la ductilite avec le temps de rupture

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Additional details

Additional titles

Original title (French)
Correlations entre l'evolution de la microstructure et la ductilite a la rupture par fluage des aciers ZCND 17/13 entre 550 deg C et 700 deg C

Publishing Information

Imprint Pagination
12 p.
Report number
CEA-CONF--5286

Conference

Title
23. Colloquium on metallurgy.
Dates
17 - 19 Jun 1980.
Place
Saclay, France.

INIS

Country of Publication
France
Country of Input or Organization
France
INIS RN
12575159
Subject category
S36: MATERIALS SCIENCE;
Resource subtype / Literary indicator
Conference, Numerical Data
Descriptors DEI
CRACKS; CREEP; DUCTILITY; ELONGATION; EXPERIMENTAL DATA; FRACTURE PROPERTIES; GRAIN BOUNDARIES; HIGH TEMPERATURE; RUPTURES; STAINLESS STEEL-ZCND17-13; TEMPERATURE DEPENDENCE
Descriptors DEC
ALLOYS; CARBON ADDITIONS; CHROMIUM ALLOYS; CHROMIUM STEELS; CHROMIUM-NICKEL STEELS; CORROSION RESISTANT ALLOYS; CRYSTAL STRUCTURE; DATA; DEFORMATION; FAILURES; INFORMATION; IRON ALLOYS; IRON BASE ALLOYS; MANGANESE ALLOYS; MECHANICAL PROPERTIES; MICROSTRUCTURE; MOLYBDENUM ALLOYS; NICKEL ALLOYS; NUMERICAL DATA; SILICON ADDITIONS; STAINLESS STEELS; STEELS; TENSILE PROPERTIES; TRANSITION ELEMENT ALLOYS