Methods for determining precise values of antiphase boundary energies in Ni3Al

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Abstract
This work is aimed at determining the importance of using image simulation programs when calculating fault energies from dislocation dissociations that have been measured using weak beam transmission electron microscopy (WB-TEM). It contains a comparison of antiphase boundary energies (γAPB) that were calculated using: measured but uncorrected dissociation distances, dissociations corrected by the method of Cockayne, and dissociations corrected using a recently developed WB image simulation program. The results indicate that, for Ni3(Al, 1%Ta), corrections can be as large as 20%. Moreover, they indicate that these corrections are different for the (111) and (010) atomic planes and that WB image simulations are needed to predict and model this anisotropic behaviour. These observations suggest that WB-TEM measurements should be supplemented with WB image simulations in order to determine precise values of stacking fault and antiphase boundary energies in anisotropic materials