Browsing by Author "Abebe, Yoseph"

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    Effective Vacancy Diffusion in NiAl Binary Alloy
    (Addis Ababa University, 2011-06) Abebe, Yoseph; Bekele, Mulugeta (PhD)
    We considered three di erent types of mechanisms by which a vacancy di uses: next nearest neighbor(NNN) jumps, triple defect mechanism and two variants of six-jumps cycles([110] and [100] bent directions). This is investigated by considering the vacancy di usion as motion of a Brownian particle in a potential eld. We used the migration energy pro le for the three types of mechanisms simulated by Kristen et al [1] to evaluate the e ective vacancy di usion coe cient at two high temperature values. We have found that their e ective vacancy di usion coe cient depends on migration energy and temperature for the three vacancy di usion mechanisms. We compared the e ective vacancy di usion coe cient for the three vacancy di usion mechanisms and identi ed that the triple defect path is the fastest than the other two di usion mechanisms