Precipitate Redistribution during Creep of Alloy 617

Journal Article · Tue Dec 01 00:00:00 EST 2009 · Metallurgical and materials Transactions A

DOI:https://doi.org/10.1007/s11661-009-0027-7· OSTI ID:968691

Schlegel, S; Hopkins, S; Young, E; Frary, M; Cole, J; Lillo, T

Nickel-based superalloys are being considered for applications within advanced nuclear power generation systems due to their high temperature strength and corrosion resistance. Alloy 617, a candidate for use in heat exchangers, derives its strength from both solid solution strengthening and the precipitation of carbide particles. However, during creep, carbides that are supposed to retard grain boundary motion are found to dissolve and re-precipitate on boundaries in tension. To quantify the redistribution, we have used electron backscatter diffraction and energy dispersive spectroscopy to analyze the microstructure of 617 after creep testing at 900 and 1000°C. The data were analyzed with respect to location of the carbides (e.g., intergranular vs. intragranular), grain boundary character, and precipitate type (i.e., Cr-rich or Mo-rich). We find that grain boundary character is the most important factor in carbide distribution; some evidence of preferential distribution to boundaries in tension is also observed at higher applied stresses. Finally, the results suggest that the observed redistribution is due to the migration of carbides to the boundaries and not the migration of boundaries to the precipitates.

• Research Organization: Idaho National Lab. (INL), Idaho Falls, ID (United States)
• Sponsoring Organization: DOE - NE
• DOE Contract Number: DE-AC07-05ID14517
• OSTI ID: 968691
• Report Number(s): INL/JOU-09-16459; TRN: US0904790
• Journal Information: Metallurgical and materials Transactions A, Vol. 40A, Issue 12
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
21 SPECIFIC NUCLEAR REACTORS AND ASSOCIATED PLANTS
ALLOYS
CARBIDES
CORROSION RESISTANCE
CREEP
DIFFRACTION
DISTRIBUTION
ELECTRONS
HEAT EXCHANGERS
HEAT RESISTING ALLOYS
MICROSTRUCTURE
NUCLEAR POWER
PRECIPITATION
SOLID SOLUTIONS
SPECTROSCOPY
STRESSES
TESTING
Alloy 617
grain boundaries
high temperature creep
Orientation Imaging Microscopy