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Title: Aging of Alloy 617 at 650 and 750 Degrees C

Technical Report ·
DOI:https://doi.org/10.2172/1070122· OSTI ID:1070122

Alloy 617 has been selected as the primary candidate for heat exchanger applications in advanced reactors. For the VHTR this application could require extended service up to a reactor outlet temperature of 950°C. A key hurdle to using this alloy in the VHTR heat exchanger application is qualifying the alloy for Section III of the ASME Boiler and Pressure Vessel Code. In order to Code qualify the material it is necessary to characterize the influence of long term aging on the mechanical behavior. Alloy 617 has been aged at 650 and 750°C for times up to 5300 hours. The microstructure after aging has been characterized using optical and transmission electron microscopies. It has been determined that in addition to carbides, a significant volume fraction of ?’ phase (Ni3Al) is formed at these temperatures. The ?’ does not contribute significantly to changing the tensile or impact properties of the aged material. It does, however, appear to increase creep resistance and impede creep crack growth.

Research Organization:
Idaho National Lab. (INL), Idaho Falls, ID (United States)
Sponsoring Organization:
DOE - NE
DOE Contract Number:
DE-AC07-05ID14517
OSTI ID:
1070122
Report Number(s):
INL/EXT-12-27974
Country of Publication:
United States
Language:
English