Plastic deformation of ferritic grains in presence of ODS particles and irradiation-induced defect clusters: A 3D dislocation dynamics simulation study

Robertson, C.; Gururaj, K.

doi:10.1016/j.jnucmat.2011.05.049

Cited by 22 publications

(23 citation statements)

References 41 publications

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“…During plastic deformation, then, the smaller, coherent oxides are more likely sheared by dislocations than bypassed via the Orowan mechanism, leaving little to no trace of dislocation loop debris (Orowan loops) surrounding the oxides [45]. Stresses associated with dislocation debris around larger, incoherent nanoclusters require mobile dislocations to cross-slip [70], resulting in limited self-work hardening. But when nanoclusters dissolve into smaller, more coherent phases, less cross-slip is necessary, resulting in larger dislocation pile-ups [45] and an increase in strain hardenability.…”

Section: Strain Hardening Exponentmentioning

confidence: 99%

Plastic zone size for nanoindentation of irradiated Fe–9%Cr ODS

Dolph

Silva

Swenson

et al. 2016

Journal of Nuclear Materials

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The objective of this study is to determine irradiation effects on the nanoindentation plastic zone morphology in a model Fe-9%Cr ODS alloy. Specimens are irradiated to 50 displacements per atom at 400°C with Fe ++ self-ions or to 3 dpa at 500°C with neutrons. The as-received specimen is also studied as a control. The nanoindentation plastic zone size is calculated using two approaches: (1) an analytical model based on the expanding spherical cavity analogy, and (2) finite element modeling (FEM). Plastic zones in all specimen conditions extend radially outward from the indenter, ~4-5 times the tip radius, indicative of fully plastic contact. Non-negligible plastic flow in the radial direction requires the experimentalist to consider the plastic zone morphology when nanoindenting ion-irradiated specimens; a single nanoindent may sample non-uniform irradiation damage, regardless of whether the indent is made top-down or in crosssection. Finally, true stress-strain curves are generated.

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Section: Strain Hardening Exponentmentioning

confidence: 99%

Plastic zone size for nanoindentation of irradiated Fe–9%Cr ODS

Dolph

Silva

Swenson

et al. 2016

Journal of Nuclear Materials

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“…The outer grain interfaces are impenetrable for dislocation segments, which allows for a realistic description of intra-granular stress (e.g. strain localization, for example) [13] [15]. The initial dislocation sources belong to the a/2 (1 0 1) <-1 -1 1> (associated with a/2 (1 -1 0) <-1 -1 1> and a/2 (0 1 1) <-1 -1 1> slip systems) slip system.…”

Section: Simulation Cases and Diat Shift Conceptmentioning

confidence: 99%

Investigation of Radiation Temperature and Straining Temperature Effects on the Screw Dislocation Mobility Evolution in Irradiated Ferritic Grains Using 3D Dislocation Dynamics

Robertson

et al. 2019

The Minerals, Metals &Amp; Materials Series

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Nuclear structural materials subjected to neutron irradiation accumulate dose-dependent, disperse defect clusters populations. Subsequent dislocation/defect interactions induce material mechanical property degradations, including hardening and embrittlement. Our goal in this work is to evaluate the effect of disperse defect clusters population on the effective dislocation mobility in ferritic Fe-Cr grains, using 3D dislocation dynamics simulations. The defect induced changes of the grain-scale mechanical response are evaluated using the recently proposed Defect-Induced Apparent Temperature (DIAT) shift concept. It is found that the DIAT shift associated with a given defect dispersion scales with the ductile to brittle transition temperature (DBTT) shift associated with exactly the same, observed defect population. The dose-dependent evolutions associated with broad irradiation temperature and straining temperature changes are investigated herein, for further exploration and validation of the DIAT shift concept.

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“…The effect of irradiation on the mechanical properties of ferritic Fe-Cr alloys has been investigated extensively through experiments [4][5][6][7][8][9][10][11][12] and modelling [13][14][15][16][17][18][19]. It is found that the irradiation-induced hardening and the reduction of ductility are significant even at low doses.…”

Section: Introductionmentioning

confidence: 99%