Antiphase boundary array

Similar antiphase boundaries form in metals with structures based upon a hexagonal close-packed array of metal atoms, such as magnesium. Condensation of vacancies upon one of the close-packed metal atom planes to form a vacancy loop, followed by subsequent collapse, will result in a hypothetical sequence. . ABABBABAB This arrangement will be unstable because of the juxtaposition... 

As in the case of twin planes, the antiphase relationship may affect only one part of the structure, for example, the cation substructure, while leaving the anion substructure unchanged. This is particularly common when the anion array can be considered to consist of a close-packed array of ions, which remains unchanged by the antiphase boundary (Fig. 3.28). 

Figure 3.22. Unit cell representations of two varieties of AuCu superlattices. For the AuCu II superlattice, M refers to the length of repeat unit, and APB indicates the antiphase boundaries between adjacent periodic arrays. Republished with the permission of the International and American Associations for Dental Research, from Determination of the AuCu Superlattice Formation Region in Gold-Copper-Silver Ternary System , Uzuka, T. Kanzawa, Y. Yasuda, K. J. Dent. Res. 1981, 60, 883 permission conveyed through Copyright Clearance Center, Inc.

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