‘Breakaway’ growth in annealed Zircaloy-2 at 353 K and 553 K

Rogerson, A.; Murgatroyd, R.A.

doi:10.1016/0022-3115(83)90151-4

Cited by 49 publications

(3 citation statements)

References 3 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Dislocation c -type loops attain a stationary value of the loop number density 10 21 m −3 [18,19]. Large faulty vacancy dislocation c loops and a loops are responsible for the accelerated process of irradiation growth as a process with an emergence of internal strains in the crystal when growth strains in all crystallographic directions are nonzero but the total volume of the system remains constant [20][21][22]. Experimental studies show that the irradiation growth depends on neutron fluence [18,23], temperature [12,21,23], alloy composition [24] and thermomechanical history [23,25,26] but a detailed mechanistic understanding is presently absent.…”

Section: Introductionmentioning

confidence: 99%

Dislocation loops growth and radiation growth in neutron irradiated Zr-Nb alloys: rate theory modelling

Wu¹,

Kharchenko²,

Lysenko³

et al. 2020

Condens. Matter Phys.

View full text Add to dashboard Cite

A generalized model to study dislocation loops growth in irradiated binary Zr-based alloys is presented. It takes into account temperature effects, efficiencies of loops to absorb point defects dependent on the loop size, an influence of locality of grain boundary sink strength, and concentration of the alloying element. This model is used to describe the dynamics of loop radii growth in zirconium-niobium alloys under neutron irradiation at reactor conditions. A growth of both loop radii and strains is studied at different grain sizes, location from grain boundaries, and concentration of niobium. It is shown that locality of grain boundary sinks results in a non-uniform deformation of the crystal inside the grains. Additionally, an introduction of niobium as an alloying element decreases the loop radii but promotes the growth of local strains inside the grains.

show abstract

Section: Introductionmentioning

confidence: 99%

Dislocation loops growth and radiation growth in neutron irradiated Zr-Nb alloys: rate theory modelling

Wu¹,

Kharchenko²,

Lysenko³

et al. 2020

Condens. Matter Phys.

View full text Add to dashboard Cite

show abstract

“…Growth at lower temperatures is a different matter. Early results for cold-worked material irradiated at 330-350 K demonstrates the same shrinkage along directions containing a high proportion c-axes as at high temperatures [10] showing that true growth is occurring (approximating constant volume), and subsequent data at 330K indicated that, as at higher temperatures the steady state growth rate is linearly proportional to the displacement damage rate [2]. In annealed material the growth rate quickly saturates (unless there are significant built-in intergranular constraints [11]) and no further change in dimensions occurs (to fluences up many 10's of displacements per atom (dpa)).…”

Section: Introductionmentioning

confidence: 85%

Irradiation Growth in Zirconium at Low Temperatures by Direct Athermal Deposition of Vacancies at Extended Sinks

Motta

Holt

Çolak

2003

Reactor Dosimetry in the 21st Century

View full text Add to dashboard Cite

Irradiation growth is a dimensional change at constant volume experienced by anisotropic materials such as Zr alloys when exposed to neutron irradiation. Growth rates at 350 K, although smaller than at 550 K, are significant, and models based on migration of point defects have difficulty rationalizing its characteristics. We propose an irradiation growth mechanism based on the direct athermal deposition of point defects onto extended sinks. Self-interstitial atoms are deposited preferentially on crystallographically aligned sinks, either because of the cascade anisotropy in the Zr hcp structure, or because of their highly anisotropic diffusion through the lattice. The model is non-saturating, and the strain rate is linearly proportional to the flux as observed. Preliminary calculations show cascades are anisotropic, which can contribute to the observed growth strains.

show abstract

“…In a fully recrystallized material, TEM shows, on the one hand, the increase in the total dislocation density in the initial IIG phase (Williams et al, 1984) and, on the other hand, the saturation of the number density of hai loops during the steady-state growth phase (Carpenter et al, 1988;Griffiths, 1988). In a later phase of service, the IIG rate increases and becomes the accelerated or 'breakaway' growth phase (Rogerson & Murgatroyd, 1983;Griffiths, 1988;Rogerson, 1988;Griffiths et al, 1989). With increased dose large faulted vacancy-type dislocation loops, known as hci loops, are also observed to form on the basal plane with a Burgers vector of 1 6 h2023i (Holt & Gilbert, 1986;Griffiths & Gilbert, 1987).…”

Section: Introductionmentioning

confidence: 99%

Characterizing dislocation loops in irradiated polycrystalline Zr alloys by X-ray line profile analysis of powder diffraction patterns with satellites

Ungár¹,

Ribárik²,

Topping³

et al. 2021

J Appl Crystallogr

View full text Add to dashboard Cite

This work extends the convolutional multiple whole profile (CMWP) line profile analysis (LPA) procedure to determine the total dislocation density and character of irradiation-induced dislocation loops in commercial polycrystalline Zr specimens. Zr alloys are widely used in the nuclear industry as fuel cladding materials in which irradiation-induced point defects evolve into dislocation loops. LPA has long been established as a powerful tool to determine the density and nature of lattice defects in plastically deformed materials. The CMWP LPA procedure is based on the Krivoglaz–Wilkens theory in which the dislocation structure is characterized by the total dislocation density ρ and the dislocation arrangement parameter M. In commercial Zr alloys irradiation-induced dislocation loops broaden the peak profiles, mainly in the tail regions, and occasionally generate small satellites next to the Bragg peaks. In this work, two challenges in powder diffraction patterns of irradiated Zr alloys are solved: (i) determination of the M values from the long tail regions of peaks has been made unequivocal and (ii) satellites have been fitted separately, using physically well established principles, in order to exclude them from the dislocation determination process. Referring to the theory of heterogeneous dislocation distributions, determination of the total dislocation density from the main peaks free of satellites has been justified. The dislocation loop structure has been characterized by the total dislocation density of loops and the M parameter correlated to the dipole character of dislocation loops. The extended CMWP procedure is applied to determine the total dislocation density, the dipole character of dislocation loops, and the fractions of 〈a〉- and 〈c〉-type loops in proton- or neutron-irradiated polycrystalline Zr alloys used in the nuclear energy industry.

show abstract

‘Breakaway’ growth in annealed Zircaloy-2 at 353 K and 553 K

Cited by 49 publications

References 3 publications

Dislocation loops growth and radiation growth in neutron irradiated Zr-Nb alloys: rate theory modelling

Dislocation loops growth and radiation growth in neutron irradiated Zr-Nb alloys: rate theory modelling

Irradiation Growth in Zirconium at Low Temperatures by Direct Athermal Deposition of Vacancies at Extended Sinks

Characterizing dislocation loops in irradiated polycrystalline Zr alloys by X-ray line profile analysis of powder diffraction patterns with satellites

Contact Info

Product

Resources

About