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Titolo:
Defect production, annealing kinetics and damage evolution in alpha-Fe: anatomic-scale computer simulation
Autore:
Soneda, N; de la Rubia, TD;
Indirizzi:
Cent Res Inst Elect Power Ind, Komae, Tokyo 201, Japan Cent Res Inst ElectPower Ind Komae Tokyo Japan 201 mae, Tokyo 201, Japan Univ Calif Lawrence Livermore Natl Lab, Livermore, CA 94550 USA Univ CalifLawrence Livermore Natl Lab Livermore CA USA 94550 A 94550 USA
Titolo Testata:
PHILOSOPHICAL MAGAZINE A-PHYSICS OF CONDENSED MATTER STRUCTURE DEFECTS ANDMECHANICAL PROPERTIES
fascicolo: 5, volume: 78, anno: 1998,
pagine: 995 - 1019
SICI:
1364-2804(199811)78:5<995:DPAKAD>2.0.ZU;2-8
Fonte:
ISI
Lingua:
ENG
Soggetto:
MOLECULAR-DYNAMICS SIMULATION; X-RAY SCATTERING; HIGH-ENERGY CASCADES; DISPLACEMENT CASCADES; POINT-DEFECT; TRANSITION-METALS; BCC METALS; COPPER; IRRADIATION; CU;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Physical, Chemical & Earth Sciences
Citazioni:
57
Recensione:
Indirizzi per estratti:
Indirizzo: Soneda, N Cent Res Inst Elect Power Ind, 2-11-1 Iwato Kita, Komae, Tokyo 201, Japan Cent Res Inst Elect Power Ind 2-11-1 Iwato Kita Komae Tokyo Japan201
Citazione:
N. Soneda e T.D. de la Rubia, "Defect production, annealing kinetics and damage evolution in alpha-Fe: anatomic-scale computer simulation", PHIL MAG A, 78(5), 1998, pp. 995-1019

Abstract

Radiation-induced microstructural and compositional changes in solids are governed by the interaction between the fraction of defects that escape their nascent cascade and the material. We use a combination of molecular dynamics (MD) and kinetic Monte Carlo (KMC) simulations to calculate the damageproduction efficiency and the fraction of freely migrating defects in alpha-Fe at 600 K. MD simulations provide information on the nature of the primary damage state as a function of recoil energy, and on the kinetics and energetics of point defects and small defect clusters. The KMC simulations use as input the MD results and provide a description of defect diffusion andinteraction over long time and length scales. For the MD simulations, we employ the analytical embedded-atom potential developed by Johnson and Oh for alpha-Fe, including a modification of the short-range repulsive interaction. We use MD to calculate the diffusivities of point defects and small defect clusters and the binding energy of small vacancy and interstitial clusters. We show that, at temperatures below about 600 K, small interstitial clusters form prismatic dislocation loops which migrate in one dimension witha very low activation energy E-a approximate to 0.1 eV. We also present results of MD simulations of displacement cascades at energies up to 20 keV. The results show that, for recoil energies above 5 keV, interstitials are produced in the form of small prismatic loops with a high probability, but vacancies are not. The MD results are then combined with a KMC simulation ofdefect interaction and diffusion, which includes the one-dimensional glideof small interstitial loops. The results provide a clear picture of the damage annealing process and show that for 20 keV cascades the escape probability for both vacancies and interstitials is about 65%. This results in a freely migrating defect production efficiency of 20% of the total defect production predicted by the modified Kinchin-Pease model (the displacements per atom standard). The capability of the hybrid MD-KMC method for carrying out long length and time scale simulations of damage evolution in irradiatedmaterials is emphasized.

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Documento generato il 06/04/20 alle ore 08:21:49