Hardening and microstructure evolution in proton-irradiated model and commercial pressure-vessel steels

Was, Gary S.; Hash, M.C.; Odette, Robert

doi:10.1080/14786430412331319974

Cited by 37 publications

(17 citation statements)

References 9 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…It is likely that they are a MnNi B 2 phase 41 . Note, such large features have also been reported following proton irradiation 42 . A FEI Titan STEM EDS line scan was performed to determine the local solute composition of the grain with large precipitates, as well as the two nearby grains which had only a few, sparsely-spaced MNSPs.…”

Section: Resultssupporting

confidence: 63%

On the Elevated Temperature Thermal Stability of Nanoscale Mn-Ni-Si Precipitates Formed at Lower Temperature in Highly Irradiated Reactor Pressure Vessel Steels

Almirall

Wells

et al. 2019

Sci Rep

View full text Add to dashboard Cite

Atom probe tomography (APT) and scanning transmission electron microscopy (STEM) techniques were used to probe the long-time thermal stability of nm-scale Mn-Ni-Si precipitates (MNSPs) formed in intermediate and high Ni reactor pressure vessel steels under high fluence neutron irradiation at ≈320 °C. Post irradiation annealing (PIA) at 425 °C for up to 57 weeks was used to determine if the MNSPs are: (a) non-equilibrium solute clusters formed and sustained by radiation induced segregation (RIS); or, (b) equilibrium G or Γ 2 phases, that precipitate at accelerated rates due to radiation enhanced diffusion (RED). Note the latter is consistent with both thermodynamic models and x-ray diffraction (XRD) measurements. Both the experimental and an independently calibrated cluster dynamics (CD) model results show that the stability of the MNSPs is very sensitive to the alloy Ni and, to a lesser extent, Mn content. Thus, a small fraction of the largest MNSPs in the high Ni steel persist, and begin to coarsen at long times. These results suggest that the MNSPs remain a stable phase, even at 105 °C higher than they formed at, thus are most certainly equilibrium phases at much lower service relevant temperatures of ≈290 °C.

show abstract

Section: Resultssupporting

confidence: 63%

On the Elevated Temperature Thermal Stability of Nanoscale Mn-Ni-Si Precipitates Formed at Lower Temperature in Highly Irradiated Reactor Pressure Vessel Steels

Almirall

Wells

et al. 2019

Sci Rep

View full text Add to dashboard Cite

show abstract

“…However, there are many differences between NI and CPI as noted in the partial list and dpa rates can strongly affect RED accelerated precipitation [4][5][6]9,25,31,33,37,38,[43][44][45][46].…”

Section: Introduction Background and Objectivementioning

confidence: 99%

On the use of charged particles to characterize precipitation in irradiated reactor pressure vessel steels with a wide range of compositions

Almirall

Wells

Yamamoto

et al. 2020

Journal of Nuclear Materials

View full text Add to dashboard Cite

Nuclear reactor lifetimes may be limited by nano-scale Cu-Mn-Ni-Si precipitates (CRPs and MNSPs) that form under neutron irradiation (NI) of pressure vessel (RPV) steels, resulting in hardening and ductile to brittle transition temperature increases (embrittlement). Physical models of embrittlement must be based on characterization of precipitation as a function of the combination of metallurgical and irradiation variables. Here we focus on rapid and convenient charged particle irradiations (CPI) to both: a) compare to precipitates formed in NI; and, b) use CPI to efficiently explore precipitation in steels with a very wide range of compositions. Atom probe tomography (APT) comparisons show NI and CPI for similar bulk steel solute contents yield nearly the same precipitate compositions, albeit with some differences in their number density, size and volume fraction (f) dose (dpa) dependence. However, the overall precipitate evolutions are very similar. Advanced high Ni (> 3 wt.%) RPV steels, with superior unirradiated properties, were also investigated at high CPI dpa. For typical Mn contents, MNSPs have Ni16Mn6Si7 or Ni3Mn2Si phase type compositions, with f values that are close to the equilibrium phase separated values. However, in steels with very low Mn and high Ni, Ni2-3Si silicide phase type precipitate compositions are observed; and when Ni is low, the precipitate compositions are close to the MnSi phase field. Low Mn significantly reduces, but does not eliminate, precipitation in high Ni steels. A comparison of dispersed barrier model predictions with measured hardening data suggests that the Ni-Si dominated precipitates are weaker dislocation obstacles than the G phase type MNSPs.

show abstract

“…The CRPs are enriched in Ni, Mn and Si. Mn-Ni rich precipitates (MNPs) containing a range of Cu, as dictated by the alloy content of this element, form at high alloy Mn and Ni levels, and are promoted by lower irradiation temperatures (<290°C) and Cu contents [2,7]. Indeed, nearly pure wellformed Mn-Ni-Si phases develop even in very low-Cu steels at sufficiently high fluence and Ni contents (possibly > 1%), although the temperature-alloy composition MNP phase boundaries have not been experimentally established.…”

Section: Introductionmentioning

confidence: 99%

Positron annihilation spectroscopy and small angle neutron scattering characterization of nanostructural features in high-nickel model reactor pressure vessel steels

Glade

Wirth

Odette

et al. 2006

Journal of Nuclear Materials

View full text Add to dashboard Cite

Hardening and microstructure evolution in proton-irradiated model and commercial pressure-vessel steels

Cited by 37 publications

References 9 publications

On the Elevated Temperature Thermal Stability of Nanoscale Mn-Ni-Si Precipitates Formed at Lower Temperature in Highly Irradiated Reactor Pressure Vessel Steels

On the Elevated Temperature Thermal Stability of Nanoscale Mn-Ni-Si Precipitates Formed at Lower Temperature in Highly Irradiated Reactor Pressure Vessel Steels

On the use of charged particles to characterize precipitation in irradiated reactor pressure vessel steels with a wide range of compositions

Positron annihilation spectroscopy and small angle neutron scattering characterization of nanostructural features in high-nickel model reactor pressure vessel steels

Contact Info

Product

Resources

About