IRRADIATION DAMAGE

V. PontikisCEA IRAMIS Laboratoire des Solides irradies

Matgen-iv.3 Lerici, Sept. 19-23, 20111Modelling & experimentsDefect configuration & mobilityChemical kineticsHardening

OutlineObjectives To remind methodological tools that led to present knowledge about irradiation damageTo emphasize on that combining experiments with theory and simulations is the key for achieving further progress

Experimental factsSwellingPhase diagramsHardeningElementary damageNature of defectsHealing

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Irradiation (fast neutrons): Swelling (cf. matgen-iv-2)Dimensional changesMicroscopic aspectsEffects of impurities20% cold-worked SS-316

T=510 C, D80 dpa

Dimensional changesMicroscopic aspectsEffects of impuritiesDimensional changesMicroscopic aspectsEffects of impurities

Cu containing 105 ppm at implanted oxygen irradiated with Cu ions.F=0.003 dp/s, 3hr, annealed 30 mn T=700 C, TEMGlowinski & Fiche, JNM (1976)

19Cr-4Al ODSferritic/martensitic9Cr-martensitic(a), (c) unirradiated (b), (d) 60 dpa, T=773 KAfter Kimura et al. (2006)3Irradiation: Hardening & Embrittlement (cf. Matgen-iv.2)

Cu clusters on dislocations (Soneda, MATGEN-IV.1)

Elongation- Baseline- IrradiatedLoad050100150200250-200-1000100200300Temperature (C)Energy (J)baselineirradiatedDBTT shift (41 J level)USE drop5Nuclear reactions(n,a) (n,p) (n,2n)

He productionIrradiation: Elementary interactionsTransfer of recoil energy if T>Td Frenkel pair creation (vacancy-interstitial)

Nuclear reactions: examples10B + n 7Li + a , 17O + n 14C + a

14N + n 14C + p , 7Be + n 7Li + p

7Be + n 2a + 2n6Irradiation: Atomic scale damageMaximum energy transfer:

The primary damage: Cascades & their structureTime scales

Displacement threshold & the formation of stable Frenkel pairs, nF=f(a,b,T,E) (KP, Kinchin & Pease, Rep. Prog. Phys. 18 (1955) 1)

but: KP overestimates the damage and linearity is questionable (SRIM, ) (Lucasson, in Fundamental Aspects of Radiation Damage in Metals, Springfield, ORNL (1975) p. 42)Time-evolution of the damage: recombination & association of FPInfluence of impurities and structural defects (dislocations, grain boundaries, )

----- Meeting Notes (11/08/11 17:32) -----N. V. Doan and R. Vascon, NIMB 135 (1998) 2077Irradiation: Time scales

8Irradiation: Displacement threshold

Jung, Atomic Collisions in Solids, Plenum (1975) 87 Jung, Radiat. Eff. 35 (1978) 1559Interstitials: Simulation I(a) Formation, Stability, Relaxations

Tetra- and octahedral sites are unstableThe split interstitial is of lowest energy

fcc Cu {100} E100(4.45 eV) *bcc Fe {110} E110(3.64 eV) < E111(4.34 eV) 3th NN10Frenkel pairs: Simulation II(b) FP annihilation in Cu (TB)*Ef 4.45 eV (exp**: 2.5 5.8 eV)Em 0.11 eV

Vacancy: Em 0.7 eV_________________________________________________________________ *Le Petitcorps 2011 (CEA, unpublished)**Wollenberger, in Physical Metallurgy (Elsevier, 1983)

At low T vacancies are immobile11Interstitials: Simulation III - Thermal migration in Cu (TB)*

*Le Petitcorps 2011 (CEA, unpublished)__________________________

12Irradiation-modified physical properties I (experiments)Aim:Measuring values of physical parameters associated with irradiation defects andpredicting damage as a function of: T, E, F, F.t

Difficulty:Interstitials (FP) are NOT thermal equilibrium defects and dp/defect is unknownMethodology

& the analogy (damage recovery chemical reaction)A(I)+B(V)AB(0), if cAB is known change cB and gain knowledge on cA

via isothermal and isochronal annealing experimentsBudin & Lucasson, Xth colloque de Mtallurgie, CEA-Saclay (1965) p. 228

13Irradiation-modified physical properties II (experiments)

Assuming the kinetics is second order:

A. Post-irradiation isothermal annealing with/without prior quenching

14Irradiation-modified physical properties III (experiments)B. Post-irradiation isochronal annealing with/without prior quenching: T=A.t

Validity conditions:2nd order kineticsCv0=CV0 quenchDetermination of: K, E, dpi, dpv15Damage thermal evolution: Resistivity experiments I

IAIB Collapse of close FPIC

ID Correlated recombinationIE Uncorrelated recombination

II Clustering, interstitial loops

III Vacancy mobility, clustering, vacancy loops & recombinationIV Vacancy loops dissociation

High energies, NFP = 20% KP (Averback, T. Diaz de la Rubbia)16

Stable interstitials: Experiments elastic constants

Cu single crystalneutronsHolder et al., Phys. Rev. B10 (1974) 349, 36317Interstitial migration: Anelastic relaxation Al-I

Spiric et al., Phys. Rev. B 15 (1977) 672, ibid. 679Stress removal: Coupling between the external stress & elastic dipoles reorientation 18Interstitial migration: Anelastic relaxation Al-II

s // {111}Spiric et al., Phys. Rev. B 15 (1977) 672, ibid. 679

19Defect reactions I: Rate equations

I. Low T1 irradiation C0 FP II. Heating up to T2 triggers SIA mobility & recombination

20Defect reactions II: Rate equations steady state

Void growth: Brailsford & Bullough, J. Nucl. Mater. 44 (1972) 121 (swelling) Heald & Speight, Acta Metall. 23 (1975) 1389

Irradiation creep: Heald & Speight, Philos. Mag. 29 (1974) 1075 Wolfer & Askin, J. Appl. Phys. 47 (1976) 791 Bullough & Willis, Philos. Mag. 31 (1975) 85521Defect association IClusters (complex defects, voids, )Dislocations (loop growth)Precipitates22Defect association II: Experiments (T & Ft effects)

Mo, T=1150 K1.0 dpa1.6 dpa2.0 dpaIgata et al., in Effects of Radiation onStructural Materials, ASTM (1979) p. 12

Interstitial loop growth, Kiritani et al.J. Phys. Soc. Japan, 38 (1975) 1677.High energies, NFP = 20% KP (Averback, T. Diaz de la Rubbia)23

Interactions Defects - Dislocations: Hardening I

Size (W0.1-0.3 eV/atModulus (few 10-2 eV/at vacancy 0.3 eV/atDipolar (few 10-3 eV/at)Chemical (strong)Friedel, Dislocations (1964)Osetsky & Bacon (2004)

Cu clusters on dislocations(Soneda, MATGEN-IV.1)

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Interactions Defects - Dislocations: Hardening IIAl-3.5% CuA535 C16 hrB190 C3 daysC350 C2 days

A: solid solution - B: GP zones - C: Precipitates>>LL25Towards non-equilibrium Phase-Diagrams ?

Adda et al., Thin Solid Films, 25 (1975) 107Ni-Si, Barbu et al., J. Appl. Phys. (1980)26

Conclusive remarksStructural materials are multicomponent complexityCrucial need of experimentsBrute force computing cannot replace understanding and model experimentsUnderstanding and engineering approaches should run in parallelSimulations are NOT Experiments (MathematicsPhysics)27MATGEN IV.3 , September 19-23, 2011 / Lerici, ItalyThank you for listening

28Time delay (s)PhenomenaPhysical parameters

10-18Energy transfer (PKA)Td,

10-13Displacement cascadeVdisplaced atoms

10-11Formation of stable FPnF, Rr,, T

>10-11Recombination, Clustering, TrappingEm, T

MetalTd

Mg10

Ti19

Al1640

Ni2335

Cu1930

Ag24

Pt34

Pb1525

V2560

Cr28

Fe1737

Mo3458

W4065