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Title: Microstructure and property tailoring of castable nanostructured alloys through thermomechanical treatments

Journal Article · · Journal of Nuclear Materials

Three types of microstructures, i.e., tempered-martensite (TM), ferrite (F), and dual-phase (TM + F), were developed in a castable nanostructured alloy that favors a high density of nanoprecipitates compared with the precipitates in current reduced-activation ferritic-martensitic steels. The effect of the distinct microstructures on tensile properties, Charpy impact toughness, and thermal helium desorption behavior was investigated with the full TM structure as a reference. The results indicated that the F domain in the TM + F structure governed the strength and slightly impaired the impact toughness. The full F structure exhibited the highest strength without compromising ductility, but it noticeably diminished impact toughness. All microstructures had a dominant helium desorption peak at ~1070 °C. The higher density of nanoprecipitates and complex boundaries and dislocations in the TM + F structure enhanced the secondary helium desorption peak and extended the shoulder peak, in contrast to the full TM structure with an enlarged desorption peak associated with the ferrite-to-austenite transformation at ~810–850 °C and the full F structure with a dominant desorption peak related to bubble migration at ~1070 °C. These results suggest that components fabricated from functionally graded microstructures could be engineered to exploit the advantages of different microstructures for demanding application requirements.

Research Organization:
Oak Ridge National Laboratory (ORNL), Oak Ridge, TN (United States)
Sponsoring Organization:
USDOE Office of Science (SC), Fusion Energy Sciences (FES); USDOE Office of Nuclear Energy (NE)
Grant/Contract Number:
AC05-00OR22725
OSTI ID:
1460207
Alternate ID(s):
OSTI ID: 1548033
Journal Information:
Journal of Nuclear Materials, Vol. 509, Issue C; ISSN 0022-3115
Publisher:
ElsevierCopyright Statement
Country of Publication:
United States
Language:
English

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