Microstructure control for high strength 9Cr ferritic-martensitic steels

Journal Article · Sun Jan 01 04:00:00 EST 2012 · Journal of Nuclear Materials

DOI:https://doi.org/10.1016/j.jnucmat.2011.12.011· OSTI ID:1033154

Tan, Lizhen ^[1]; Hoelzer, David T ^[1]; Busby, Jeremy T ^[1]; Sokolov, Mikhail A ^[1]; Klueh, Ronald L ^[1]

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1. ORNL

Ferritic-martensitic (F-M) steels with 9 wt.%Cr are important structural materials for use in advanced nuclear reactors. Alloying composition adjustment, guided by computational thermodynamics, and thermomechanical treatment (TMT) were employed to develop high strength 9Cr F-M steels. Samples of four heats with controlled compositions were subjected to normalization and tempering (N&T) and TMT, respectively. Their mechanical properties were assessed by Vickers hardness and tensile testing. Ta-alloying showed significant strengthening effect. The TMT samples showed strength superior to the N&T samples with similar ductility. All the samples showed greater strength than NF616, which was either comparable to or greater than the literature data of the PM2000 oxide-dispersion-strengthened (ODS) steel at temperatures up to 650 C without noticeable reduction in ductility. A variety of microstructural analyses together with computational thermodynamics provided rational interpretations on the strength enhancement. Creep tests are being initiated because the increased yield strength of the TMT samples is not able to deduce their long-term creep behavior.

• Research Organization: Oak Ridge National Laboratory (ORNL); Shared Research Equipment Collaborative Research Center
• Sponsoring Organization: USDOE
• DOE Contract Number: AC05-00OR22725
• OSTI ID: 1033154
• Journal Information: Journal of Nuclear Materials, Journal Name: Journal of Nuclear Materials Journal Issue: 1-3 Vol. 422; ISSN 0022-3115; ISSN JNUMAM
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
BUILDING MATERIALS
CREEP
DUCTILITY
MECHANICAL PROPERTIES
MICROSTRUCTURE
REACTORS
STEELS
TEMPERING
TESTING
THERMODYNAMICS
THERMOMECHANICAL TREATMENTS
VICKERS HARDNESS
YIELD STRENGTH