Effects of long-term thermal aging on bulk and local mechanical behavior of ferritic-austenitic duplex stainless steels

Journal Article · Wed Mar 21 00:00:00 EDT 2018 · Materials Science and Engineering. A. Structural Materials: Properties, Microstructure and Processing

DOI:https://doi.org/10.1016/j.msea.2018.02.058· OSTI ID:1545026

Schwarm, Samuel C. ^[1]; Mburu, Sarah ^[2]; Kolli, Ratna P. ^[2]; Perea, Daniel E.  ^[3]; Ankem, Sreeramamurthy ^[2]

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1. University of Maryland at College Park
2. University of Maryland
3. BATTELLE (PACIFIC NW LAB)

Ferritic-austenitic duplex stainless steels (DSS) undergo significant thermal aging embrittlement in service in light water reactors. Specimens of cast CF–3 and CF–8 DSS have been laboratory aged for up to 17,200 h at four different temperatures (280, 320, 360, 400 °C) in order to characterize the aging evolution and mechanical properties. Standard Charpy V-Notch (CVN) impact testing and tensile testing are employed to measure the progression of embrittlement of the steels. Concurrently, nanoindentation measurements are performed to measure the hardening of the individual ferrite and austenite phases. Atom probe tomography (APT) analysis of the ferrite and austenite phases elucidates the relationship between spinodal decomposition of the ferrite and the mechanical effects of aging. The results are discussed to relate the effects of the local microstructure and property changes in the ferrite phase on the overall bulk mechanical evolution of these steels.

• Research Organization: Pacific Northwest National Lab. (PNNL), Richland, WA (United States)
• Sponsoring Organization: USDOE
• DOE Contract Number: AC05-76RL01830
• OSTI ID: 1545026
• Report Number(s): PNNL-SA-136058
• Journal Information: Materials Science and Engineering. A. Structural Materials: Properties, Microstructure and Processing, Vol. 720
• Country of Publication: United States
• Language: English