Effects of solute and vacancy segregation on antiphase boundary migration in stoichiometric and Al-rich Fe₃Al: a phase-field simulation study
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FEAL2009ProcKoizumi091112 copy.pdf
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Author(s)
Koizumi, Yuichiro
Allen, Samuel Miller
Ouchi, Masayuki
Minamino, Yoritoshi
Date Issued
February 2010
Journal
Intermetallics
Publisher
Elsevier B.V.
Citation
Koizumi, Yuichiro et al. “Effects of Solute and Vacancy Segregation on Antiphase Boundary Migration in Stoichiometric and Al-rich Fe₃Al: A Phase-field Simulation Study.” Intermetallics 18.7 (2010): 1297–1302.
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Author's final manuscript
Abstract
Effects of segregation of solute atoms and vacancies on migration of antiphase boundaries (APBs) in stoichiometric (Fe-25 at%Al) and Al-rich (Fe-28 at%Al) Fe₃Al at 673 K have been studied using a phase-field method in which local vacancy concentration is taken into account [Koizumi Y, Allen SM, Minamino Y. Acta Mater 2008;56:5861, ibid. 2009;57:3039]. Boundary mobility (M) of APBs having different phase-shift vectors of a/4<111> and a/2<100> (hereafter denoted as B2-APB and D0₃-APB, respectively) was evaluated by measuring the boundary velocity of shrinking circular APBs. Similar effects of the segregation on the migration of B2-APBs were observed in both compositions. Vacancies segregated and Al-atoms were depleted at B2-APBs in both compositions. Vacancy concentration at B2-APBs was up to 80% higher than that in the bulk. As a result, the migration of B2-APBs was greatly enhanced by the vacancy segregation. In contrast, the segregation to D0₃-APBs showed a marked composition dependence. Vacancies were depleted and Al-atoms segregated at D0₃-APBs in the Al-rich Fe₃Al, whereas vacancies segregated and Al-atoms were depleted at D0₃-APB in the stoichiometric Fe₃Al. The Al segregation in the Al-rich Fe3Al decreased M of D0₃-APBs much more significantly than the Al-depletion in the stoichiometric Fe₃Al. As the APDs shrank, D0₃-APBs broke away from the segregation atmospheres and the M increased rapidly in both compositions. A greater increase in the M due to the breakaway was observed in the Al-rich Fe₃Al than in Fe₃Al with the stoichiometric composition.
MIT Department
Massachusetts Institute of Technology. Department of Materials Science and Engineering
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DOI of Published Version
http://dx.doi.org/10.1016/j.intermet.2009.12.016
