22.08.2015   Comprehensive nuclear materials

Defect Production in Fe-C

Calder and coworkers examined the effect of carbon on defect production in the Fe-C system with the carbon concentration between 0 and 1.0atom%.125 The Fe potential was developed by Ackland and coworkers.134 The form of this potential is similar to

the Finnis-Sinclair potential discussed throughout this chapter, but the absolute level of defect produc­tion is somewhat lower. Simulations were carried out at temperatures of 100 and 600 K for cascade energies of 5, 10, and 20keV. Thirty simulations were carried out at each condition to ensure a good statistical sampling. No systematic effect of carbon was observed on either stable defect formation or the clustering of
vacancies and interstitials. Analysis of the octahedral sites around vacancies and interstitials revealed a sta­tistically significant association of carbon atoms with both vacancies and SIAs. This indicates an effective trapping, which is consistent with the solute-defect binding energies. Although primary damage formation was not affected by carbon, the trapping mechanism could have an effect on damage accumulation.

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Подпись:20 keV, 100 K copper

a 20 keV cascade at 100 K in Fe (a) and Cu (b). Note larger SIA

Figure 36 Comparison of stable defect production from clusters in (b).

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Figure 37 The number of SIAs and vacancies in clusters per cascade as a function of cascade energy in (a) a-zirconium and (b) a-iron at 100 K. The values were obtained by averaging over all cascades at each energy. Reproduced from Bacon, D. J.; Gao, F.; Osetsky, Yu. N. J. Nucl. Mater. 2000, 276, 1-12.