When the spinel was deformed in compression at 400C along <110>, the primary slip plane was found to be {111}, with cross-slip occurring on a {001} plane. A comparison of weak-beam images of dislocations from both systems indicated that all of the dislocations which belonged to the primary slip plane were dissociated out of the {111} plane, regardless of the character of the dislocation. It was proposed that deformation occurred via the motion of dislocations in their dissociated state, and that the partial dislocations actually glided on parallel glide planes. Movement of these dissociated dislocations was then accompanied by a concurrent migration of the stacking fault which took place via a local shuffling of the cations. A stacking-fault energy of 530mJ/m2 for conservative dissociation at 400C on {001} was determined from weak-beam images of screw dislocations.

Dissociation of Dislocations in MgAl2O4 Spinel Deformed at Low Temperatures. P.Veyssié, C.B.Carter: Philosophical Magazine Letters, 1988, 57[4], 211-20