The question of whether constitutional vacancies occurred in B2 intermetallic compounds was considered, and a recently proposed model for point-defect formation in such compounds was developed. In contrast to the results of Ren and Otsuka, it was shown that the statistical thermodynamic model - when applied to the available experimental data for B2 Ni1-xAlx – did not lead to the conclusion that constitutional vacancies did not exist. All of the available data, apart from the vacancy concentrations determined experimentally by Kogachi et al., were found to be fully consistent with the triple-defect model.

Thermodynamics of Constitutional and Thermal Point Defects in B2 Ni1-xAlx. J.Breuer, F.Sommer, E.J.Mittemeijer: Philosophical Magazine A, 2002, 82[3], 479-96

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