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IRRADIATION DAMAGE V. Pontikis CEA – IRAMIS – Laboratoire des Solides irradies. Matgen-iv.3 – Lerici , Sept. 19-23, 2011. Outline. Modelling & experiments Defect configuration & mobility Chemical kinetics Hardening. Experimental facts Swelling Phase diagrams Hardening
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IRRADIATION DAMAGEV. PontikisCEA – IRAMIS –Laboratoire des Solidesirradies Matgen-iv.3 – Lerici, Sept. 19-23, 2011
Outline • Modelling & experiments • Defect configuration & mobility • Chemical kinetics • Hardening • Experimental facts • Swelling • Phase diagrams • Hardening • Elementary damage • Nature of defects • Healing • Objectives • To remind methodological tools that led to present knowledge about irradiation damage • To emphasize on that combining experiments with theory and simulations is the key for achieving further progress
Irradiation (fast neutrons): Swelling (cf. matgen-iv-2) • Dimensional changes • Microscopic aspects • Effects of impurities • Dimensional changes • Microscopic aspects • Effects of impurities • Dimensional changes • Microscopic aspects • Effects 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, TEM Glowinski & Fiche, JNM (1976) 20% cold-worked SS-316 T=510 °C, D≈80 dpa After Kimura et al. (2006) 9Cr-martensitic 19Cr-4Al ODS ferritic/martensitic (a), (c) unirradiated (b), (d) 60 dpa, T=773 K
Ni(Si (4%) Ni3Si Ni(Si) + Ni3Si Ni(Si) Ni Si Irradiation: Phase Diagram (cf. matgen-iv.1) TEM DF A. Barbuand A.J. Ardell, ScriptaMetall. 9 (1975) 1233
Load 250 baseline - Baseline -Irradiated irradiated 200 Energy (J) 150 100 Elongation 50 0 -200 -100 0 100 200 300 USE drop Temperature (°C) DBTT shift (41 J level) Irradiation: Hardening & Embrittlement (cf. Matgen-iv.2) Cu clusters on dislocations (Soneda, MATGEN-IV.1)
Irradiation: Elementary interactions Nuclear reactions: examples 10B +n 7Li + a , 17O + n 14C + a 14N + n 14C + p , 7Be + n 7Li + p 7Be + n 2a + 2n Nuclear reactions (n,a) – (n,p) – (n,2n) He production Transfer of recoil energy if T>Td Frenkel pair creation (vacancy-interstitial)
Irradiation: Atomic scale damage • Maximum energy transfer: • The primary damage: Cascades & their structure • Time 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 FP • Influence of impurities and structural defects (dislocations, grain boundaries, …)
Irradiation: Displacement threshold Jung, Atomic Collisions in Solids, Plenum (1975) 87 Jung, Radiat. Eff. 35 (1978) 155
Interstitials: Simulation I • (a) Formation, Stability, Relaxations • Tetra- and octahedral sites are unstable • The split interstitial is of lowest energy • fcc Cu {100} – E100(4.45 eV) * • bcc Fe {110} E110(3.64 eV) < E111(4.34 eV) <E100(4.64 eV)** • Long-range relaxations R>3th NN __________________________ *Le Petitcorps 2011 (CEA, unpublished) **CCF et al. Phys. Rev. Lett., 92 (2004) 175503
Frenkel pairs: Simulation II • (b) FP annihilation in Cu (TB)* • Ef≈ 4.45 eV (exp**: 2.5 – 5.8 eV) • Em≈ 0.11eV • Vacancy: Em≈ 0.7eV At low T vacancies are immobile _________________________________________________________________ *Le Petitcorps 2011 (CEA, unpublished) **Wollenberger, in Physical Metallurgy (Elsevier, 1983)
Interstitials: Simulation III -Thermal migration in Cu (TB)* __________________________ *Le Petitcorps 2011 (CEA, unpublished)
Irradiation-modified physical properties I (experiments) Aim: Measuring values of physical parameters associated with irradiation defects and predicting damage as a function of: T, E, F, F.t Difficulty: Interstitials (FP) are NOT thermal equilibrium defects and dp/defect is unknown & 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 experiments Methodology Budin & Lucasson, Xthcolloque de Métallurgie, CEA-Saclay (1965) p. 228
Irradiation-modified physical properties II (experiments) A. Post-irradiation isothermal annealing with/without prior quenching Assuming the kinetics is second order:
Irradiation-modified physical properties III (experiments) B. Post-irradiation isochronal annealing with/without prior quenching: T=A.t • 2nd order kinetics • Cv0=CV0 quench Validity conditions: Determination of: K, E, dpi, dpv
Damage 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 & recombination • IV Vacancy loops dissociation
Stable interstitials: Experiments – elastic constants Cu single crystal neutrons Holder et al., Phys. Rev. B10 (1974) 349, 363
Interstitial migration: Anelastic relaxation Al-I Coupling between the external stress & elastic dipoles reorientation Stress removal: Spiric et al., Phys. Rev. B 15 (1977) 672, ibid. 679
Interstitial migration: Anelastic relaxation Al-II s // {111} Spiric et al., Phys. Rev. B 15 (1977) 672, ibid. 679
Defect reactions I: Rate equations I. Low T1 irradiation C0 FP – II. Heating up to T2 triggers SIA mobility & recombination
Defect 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) 855
Defect association I • Clusters (complex defects, voids, …) • Dislocations (loop growth) • Precipitates
Defect association II: Experiments (T & Ft effects) Mo, T=1150 K 1.0 dpa Igata et al., in Effects of Radiation on Structural Materials, ASTM (1979) p. 12 1.6 dpa Interstitial loop growth, Kiritani et al. J. Phys. Soc. Japan, 38 (1975) 1677. 2.0 dpa
Interactions Defects - Dislocations: Hardening I Friedel, Dislocations (1964) • Size (W≈0.1-0.3 eV/at • Modulus (≈few 10-2eV/at • vacancy ≈0.3 eV/at • Dipolar (few 10-3eV/at) • Chemical (strong) Cu clusters on dislocations (Soneda, MATGEN-IV.1) Osetsky & Bacon (2004)
Interactions Defects - Dislocations: Hardening II Al-3.5% Cu A: solid solution - B: GP zones - C: Precipitates L ≈ >>L
Towards non-equilibrium Phase-Diagrams ? Adda et al., Thin Solid Films, 25 (1975) 107 Ni-Si, Barbu et al., J. Appl. Phys. (1980)
Conclusive remarks • Structural materials are multicomponent complexity • Crucial need of experiments • Brute force computing cannot replace understanding and model experiments • Understanding and engineering approaches should run in parallel • Simulations are NOT Experiments (Mathematics≠Physics)
Thank you for listening MATGEN – IV.3 , September 19-23, 2011 / Lerici, Italy