Deformation processes involving interfacial dislocation mechanisms in twin boundaries of hexagonal close-packed metals were described. The topological properties of individual defects, namely their Burgers vectors, b, and step heights, h, were defined rigorously, and the magnitude of the diffusional flux of material required for motion of a defect along an interface was expressed quantitatively in terms of b, h and the material's density. This framework enables interactions between defects to be treated and, in particular, enables identification of processes that were conservative. Using these topological arguments, it was shown that sessile interfacial defects in twins need not block further twinning and that the recently discovered Serra-Bacon twinning mechanism was conservative. The possible wider significance of the Serra-Bacon-type mechanism that caused localized lateral growth of twins was also considered briefly in the context of the deformation of hexagonal close-packed and martensitic materials.

Interfacial Deformation Mechanisms in Hexagonal-Close-Packed Metals. R.C.Pond, S.Celotto: Metallurgical and Materials Transactions A, 2002, 33[3A], 801-7