It was recalled that deformation-twinning of face-centered cubic and body-centered cubic metals could lead to void formation where, as a first step, hollow channels formed at the intersections of twin lamellae. Such channels were known as so-called Rose channels. In the second step, sectioning of the Rose channels by slip resulted in voids and vacancy clusters. This two-step mechanism was thought to account for electron-microscopic observations of the formation of vacancy clusters by so-called plastic-deformation-without-dislocations. The previously enigmatic abundance of vacancy clusters, and absence of self-interstitial clusters, were found to be natural consequences of the inherent asymmetry of twinning.

Production of Lattice Vacancies in Metals by Deformation Twinning. A.Seeger: Philosophical Magazine Letters, 2007, 87[2], 95-102