The formation and spread of local shear in crystals with forest dislocations was investigated by means of chemical etching, by transmission electron microscopy, and by the placing of reference grids on the worked part of single crystals. It was shown that a necessary criterion for the formation of local shear was the presence of a high density of pyramidal dislocations. Their transformation resulted in the formation of basal dislocations, and in the development of large local shears. The local shears in the {11•2} plane could attain 104%.

M.E.Bosin, F.F.Lavrentev, V.N.Nikiforenko: Fizika Tverdogo Tela, 1996, 38[12], 3619-24 (Physics of the Solid State, 1996, 38[12], 1972-5)