MODELS OF THE CORES OF DISLOCATIONS IN METALS AND DISCLINATIONS IN LIQUID-CRYSTALS

The development of dislocation core models in metals with non-close-pa cked crystalline structure is reviewed. The paper starts with the Peie rls-Nabarro model generalized to the case of non-planar cores to descr ibe dislocation splitting in bcc metals. Atomistic studies of dislocat ions cores in bcc metals and intermetallic compounds with L1(2) and B2 structures are then discussed and the principal features of non-plana r cores emphasized. Finally, an analogy between dislocations in solid and disclination in liquid crystals is presented and similarities and differences in the treatment of core structures of these defects in so lid and liquid crystals discussed.