This work focuses on fundamental understanding of microstructure evolution of nanostructured ferritic alloy(NFA) and 25 vol.% Cr3C2 coated Si C(Cr3C2@Si C)-NFA composite during spark plasma sintering at950°C and ...This work focuses on fundamental understanding of microstructure evolution of nanostructured ferritic alloy(NFA) and 25 vol.% Cr3C2 coated Si C(Cr3C2@Si C)-NFA composite during spark plasma sintering at950°C and the following thermal treatment at 1000°C. A unique bi-phase microstructure with distinct Cr-rich and Si-rich phases has been observed for the 25 vol.% Cr3C2@Si C-NFA composite, while for the NFA sample, the traditional large grain microstructure remains. Grain sizes are significantly smaller for the25 vol.% Cr3C2@Si C-NFA composite compared to those for the pure NFA, which can be attributed to the presence of grain boundary phases in the composite sample. During the thermal treatment, microstructure features can be directly correlated with the dissolution kinetics and phase diagrams calculated using Thermo-Calc/DICTRA/PRISMA~?.展开更多
This work focuses on irradiation behaviors of a novel silicon carbide and carbon coated nanostructured ferritic alloy(SiC-C@NFA)composite for potential applications as a cladding and structural material for next gener...This work focuses on irradiation behaviors of a novel silicon carbide and carbon coated nanostructured ferritic alloy(SiC-C@NFA)composite for potential applications as a cladding and structural material for next generation nuclear reactors.The SiC-C@NFA samples were irradiated with 1 MeV Kr ions up to 10 dpa at 300 and 4500 C.Microstructures and defect evolution were studied in-situ at the IVEM-Tandem facility at Argonne National Laboratory.The effects of ion irradiation on various phases such asα-ferrite matrix,(Fe,Cr)_(7)C_(3),and(Ti,W)C precipitates were evaluated.Theα-ferrite matrix showed a continuous increase in dislocation density along with spatial ordering of dislocation loops(or loop strings)at>5 dpa.The size of the dislocation loops at 450℃was larger than that at 300℃.The nucleation and growth of new(Ti,W)C precipitates inα-ferrite grains were enhanced with the ion dose at 450℃.This study provides new insight into the irradiation resistance of the SiC-C@NFA system.展开更多
基金supported financially by the Office of Nuclear Energy of Department of Energy(No.#DE-NE0008264)。
文摘This work focuses on fundamental understanding of microstructure evolution of nanostructured ferritic alloy(NFA) and 25 vol.% Cr3C2 coated Si C(Cr3C2@Si C)-NFA composite during spark plasma sintering at950°C and the following thermal treatment at 1000°C. A unique bi-phase microstructure with distinct Cr-rich and Si-rich phases has been observed for the 25 vol.% Cr3C2@Si C-NFA composite, while for the NFA sample, the traditional large grain microstructure remains. Grain sizes are significantly smaller for the25 vol.% Cr3C2@Si C-NFA composite compared to those for the pure NFA, which can be attributed to the presence of grain boundary phases in the composite sample. During the thermal treatment, microstructure features can be directly correlated with the dissolution kinetics and phase diagrams calculated using Thermo-Calc/DICTRA/PRISMA~?.
基金supported financially by the Office of Nuclear Energy of Department of Energy(No.#DE-NE0008264)supported by DOE as a part of Rapid Turnaround Experiments(RTE)award of Nuclear Science User Facilities(NSUF)。
文摘This work focuses on irradiation behaviors of a novel silicon carbide and carbon coated nanostructured ferritic alloy(SiC-C@NFA)composite for potential applications as a cladding and structural material for next generation nuclear reactors.The SiC-C@NFA samples were irradiated with 1 MeV Kr ions up to 10 dpa at 300 and 4500 C.Microstructures and defect evolution were studied in-situ at the IVEM-Tandem facility at Argonne National Laboratory.The effects of ion irradiation on various phases such asα-ferrite matrix,(Fe,Cr)_(7)C_(3),and(Ti,W)C precipitates were evaluated.Theα-ferrite matrix showed a continuous increase in dislocation density along with spatial ordering of dislocation loops(or loop strings)at>5 dpa.The size of the dislocation loops at 450℃was larger than that at 300℃.The nucleation and growth of new(Ti,W)C precipitates inα-ferrite grains were enhanced with the ion dose at 450℃.This study provides new insight into the irradiation resistance of the SiC-C@NFA system.
