Embrittlement of laboratory- and reactor-aged CF-3, CF-8, and CF-8M duplex stainless steels

Conference · Sun Oct 01 00:00:00 EDT 1989

OSTI ID:5422320

Chung, H M; Leax, T R ^[1]

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1. Argonne National Lab., IL (USA)

Cast duplex stainless steels of CF-3, CF-8, and CF-8M grades, containing a wide range of chemical composition and ferrite content, were aged in the laboratory at 270 to 450{degree}C to evaluate the kinetics and mechanisms of thermal-aging embrittlement. CF-8 and CF-8A steels were also obtained from components of BWRs and PWRs after service of 12 to 22 yr. After mechanical-property (i.e., Charpy impact, tensile, and J-R curve) and microhardness tests, the aged specimens were examined by transmission electron microscopy and field-ion atom-probe techniques to elucidate the aging mechanisms and identify critical factors that control the embrittlement kinetics. From the results of microstructural characterization, the primary and secondary embrittlement mechanisms were identified. A mechanistic correlation was obtained between the microstructural characteristics and the activation energy of aging (i.e., the temperature dependence of the aging kinetics) for steels with a range of chemical compositions and subjected to different fabrication and thermal-treatment conditions. The unified correlation, based on spinodal decomposition influenced by G-phase nucleation and growth in ferrite and M{sub 23}C{sub 6} precipitation on ferrite-austenite boundaries, provides a good explanation of the complex behavior of the activation energy (ranging from 18 to 55 kcal/mole) regardless of grade, chemical composition, or fabrication process. 27 refs., 13 figs., 6 tabs.

• Research Organization: Argonne National Lab., IL (USA)
• Sponsoring Organization: USNRC
• DOE Contract Number: W-31109-ENG-38
• OSTI ID: 5422320
• Report Number(s): CONF-8908175-1; ON: DE90002777
• Resource Relation: Conference: International workshop on intermediate-temperature embrittlement processes in duplex stainless steels, Oxford (UK), 1-2 Aug 1989
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
21 SPECIFIC NUCLEAR REACTORS AND ASSOCIATED PLANTS
STAINLESS STEELS
EMBRITTLEMENT
ACTIVATION ENERGY
AGING
BWR TYPE REACTORS
CARBIDES
CHEMICAL COMPOSITION
FERRITE
MECHANICAL PROPERTIES
MICROSTRUCTURE
NIOBIUM CARBIDES
PRECIPITATION
SHIPPINGPORT REACTOR
ALLOYS
CARBON ADDITIONS
CARBON COMPOUNDS
CRYSTAL STRUCTURE
ENERGY
ENRICHED URANIUM REACTORS
HIGH ALLOY STEELS
IRON ALLOYS
IRON BASE ALLOYS
NIOBIUM COMPOUNDS
POWER REACTORS
PWR TYPE REACTORS
REACTORS
REFRACTORY METAL COMPOUNDS
SEPARATION PROCESSES
STEELS
THERMAL REACTORS
TRANSITION ELEMENT COMPOUNDS
WATER COOLED REACTORS
WATER MODERATED REACTORS
360103* - Metals & Alloys- Mechanical Properties
210200 - Power Reactors
Nonbreeding
Light-Water Moderated
Nonboiling Water Cooled
210100 - Power Reactors
Nonbreeding
Light-Water Moderated
Boiling Water Cooled