Cascade annealing simulations of bcc iron using object kinetic Monte Carlo

Haixuan Xu, Yury N. Osetsky, Roger E. Stoller

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40 Scopus citations

Abstract

Simulations of displacement cascade annealing were carried out using object kinetic Monte Carlo based on an extensive MD database including various primary knock-on atom energies and directions. The sensitivity of the results to a broad range of material and model parameters was examined. The diffusion mechanism of interstitial clusters has been identified to have the most significant impact on the fraction of stable interstitials that escape the cascade region. The maximum level of recombination was observed for the limiting case in which all interstitial clusters exhibit 3D random walk diffusion. The OKMC model was parameterized using two alternative sets of defect migration and binding energies, one from ab initio calculations and the second from an empirical potential. The two sets of data predict essentially the same fraction of surviving defects but different times associated with the defect escape processes. This study provides a comprehensive picture of the first phase of long-term defect evolution in bcc iron and generates information that can be used as input data for mean field rate theory (MFRT) to predict the microstructure evolution of materials under irradiation. In addition, the limitations of the current OKMC model are discussed and a potential way to overcome these limitations is outlined.

Original languageEnglish
Pages (from-to)102-109
Number of pages8
JournalJournal of Nuclear Materials
Volume423
Issue number1-3
DOIs
StatePublished - Apr 2012

Funding

Research at the Oak Ridge National Laboratory supported as part of the Center for Defect Physics, an Energy Frontier Research Center funded by the US Department of Energy, Office of Science, Office of Basic Energy Sciences under Award Number ERKCS99.

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