Sous-joints de dislocations et dissociations dans le ferrite de nickel déformé plastiquement à 0,85 TF

Abstract
SUB-GRAIN BOUNDARIES AND DISSOCIATIONS OF DISLOCATIONS IN SPINEL FERRITE Ni0-66Fe2-34O4 PLASTICALLY DEFORMED AT 0-85 TM Hexagonal sub-grain boundaries in the spinel Ni0·66Fe2·34O4 deformed at 0·85 T M have been studied by electron microscopy. They are most frequently dissociated into two parallel hexagonal sub-grain boundaries connected by a stacking fault strip only. This configuration must be observed in any compound whose structure allows perfect dislocation dissociation into two partial dislocations with collinear Burgers vectors. These networks are formed mainly by climb. {111} planes are seldom observed to be dissociation planes of dislocations. A weak beam contrast consistent with dissociation into four sub-partials is shown