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

Abstract

SUB-GRAIN BOUNDARIES AND DISSOCIATIONS OF DISLOCATIONS IN SPINEL FERRITE Ni_0-66Fe_2-34O₄ PLASTICALLY DEFORMED AT 0-85 T_M

Hexagonal sub-grain boundaries in the spinel Ni_0·66Fe_2·34O₄ 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