Appreciable stacking-disordering within basal planes, including stacking faults, basal-plane twinning or entirely disordered stacking and shearing of lattice planes, delamination and kink bands, were frequently found in most hexagonal grains after milling. It was clear that most of these high-energy defect structures were created by simultaneous shearing rather than by the dissociation of a perfect dislocation. Following frequent shearing, the unit-cell shape of the [11•0] lattice image changed from rectangular to rhomboid. Non-basal plane defects such as half Frank loops and interstitial or vacancy loops with high-energy stacking configurations were also frequently found. These deformation structures arose from the inherent structural characteristics of hexagonal BN and were quite different to those found in face-centered cubic metals such as Cu.

Stacking Disordering in Hexagonal BN Induced by Shearing under Ball-Milling. J.Y.Huang, X.B.Jia, H.Yasuda, H.Mori: Philosophical Magazine Letters, 1999, 79[5], 217-24