Intergranular fracture in irradiated Inconel X-750 containing very high concentrations of helium and hydrogen

Judge, C. D.; Gauquelin, Nicolas; Walters, Lori; Wright, M.G.; Cole, James I.; Madden, James W.; Botton, Gianluigi A.; Griffiths, M.

doi:10.1016/j.jnucmat.2014.10.008

Cited by 90 publications

(41 citation statements)

References 14 publications

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“…[8]) predicts the yield strength increase caused by arbitrary defects impeding dislocation motion with number defect density N, diameter d, and glide dislocation Burgers vector magnitude b. [41] This model uses a dislocation line tension approximation and considers all defects within a thin plate to interact with equal obstacle strength with the dislocation.…”

Section: Modeling Of Irradiation-induced Hardeningmentioning

confidence: 99%

“…Then, the total increase in yield strength can be predicted using the superposition principle to combine the independent defect hardening contributions according to Eq. [8].…”

Section: Modeling Of Irradiation-induced Hardeningmentioning

confidence: 99%

“…[6] Although the underlying mechanism leading to the mechanical properties degradation is not yet fully understood, some studies have been carried out on the microstructural changes of ex-service (neutron-irradiated) spacers. [5,7,8] Furthermore, some studies have tried to emulate the effect of neutron irradiation on the microstructure of X-750 alloy by means of employing heavy ion irradiation under controlled irradiation conditions. [9][10][11] The results show that irradiation may affect the microstructure in different ways depending on irradiation temperature, irradiation dose, and dose rate.…”

Section: Introductionmentioning

confidence: 99%

“…[8] In particular, the (n,a) transmutation reaction, 59 Ni + n fi 56 Fe + 4 He, is the result of the high neutron capture cross-section of 59 Ni over a wide range of neutron energies, leading to a high production rate of helium atoms (about 300 appm/dpa) in X-750 during service in the CANDU reactor. [7] The helium generation is always considered as a serious issue since it can degrade the mechanical properties, significantly.…”

Section: Introductionmentioning

confidence: 99%

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Nano-scale Mechanical Properties and Microstructure of Irradiated X-750 Ni-Based Superalloy

Changizian

Brooks

Yao

et al. 2017

Metall Mater Trans A

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This study investigates the effect of irradiation on the mechanical properties of a Ni-based superalloy, X-750. 40 MeV Ni + ions were used to irradiate the X-750 up to 1 dpa with and without 5000 appm helium pre-implantation at room temperature and 400°C. Nano-indentation hardness tests were carried out at room temperature in the depth range of 200 to 1400 nm before and after irradiation. Cross-sectional TEM observations were performed on the irradiated materials to correlate the mechanical results with the microstructural evolution. The results show that helium pre-implantation enhances the irradiation-induced hardening due to generating a high density of small cavities and promoting the formation of larger Frank loops. In addition, nano-scale mechanical tests reveal that changing the subsequent Ni ion irradiation temperature from room temperature to 400°C, leads to changing of the mechanical response from a softening behavior to an irradiation-induced hardening. The c¢ precipitates became disordered after irradiation at room temperature, whereas the c¢-phase remained ordered during irradiation at 400°C. The softening effect of the c¢ instability outweighed the hardening impact of irradiation-induced defects such as cavities and Frank loops, leading to a hardness reduction for the room-temperature-irradiated material. Three different obstacle-hardening models were employed to assess the individual impact of each type of defect on the material's overall strength enhancement. Furthermore, the superposition principle was used for each model to estimate the overall irradiation-induced strengthening, which is compared to the results from the nano-hardness measurements.

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Section: Modeling Of Irradiation-induced Hardeningmentioning

confidence: 99%

“…Then, the total increase in yield strength can be predicted using the superposition principle to combine the independent defect hardening contributions according to Eq. [8].…”

Section: Modeling Of Irradiation-induced Hardeningmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Nano-scale Mechanical Properties and Microstructure of Irradiated X-750 Ni-Based Superalloy

Changizian

Brooks

Yao

et al. 2017

Metall Mater Trans A

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“…Thus, it precipitates out of solution into nanometer-scale bubbles [58]. These precipitates are usually deleterious to the properties of the solid, e.g., they lead to embrittlement in Ni-base alloys [59] and surface damage in plasma-facing materials [60]. Much effort has been invested into mitigating damage induced by implanted He, especially in materials for nuclear energy [61][62][63][64].…”

Section: He In Fcc/bcc Composites: Detecting Density Changesmentioning

confidence: 99%

Probing Interfaces in Metals Using Neutron Reflectometry

Demkowicz

Majewski

2016

Metals

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Solid-state interfaces play a major role in a variety of material properties. They are especially important in determining the behavior of nano-structured materials, such as metallic multilayers. However, interface structure and properties remain poorly understood, in part because the experimental toolbox for characterizing them is limited. Neutron reflectometry (NR) offers unique opportunities for studying interfaces in metals due to the high penetration depth of neutrons and the non-monotonic dependence of their scattering cross-sections on atomic numbers. We review the basic physics of NR and outline the advantages that this method offers for investigating interface behavior in metals, especially under extreme environments. We then present several example NR studies to illustrate these advantages and discuss avenues for expanding the use of NR within the metals community.

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