Climb dissociation of network dislocations in non–stoichiometric Mg–Al spinel

Transmission electron microscopy of single-cryatal non-stoichiometric spinel (MgO. 3–5 A12O3) deformed in compression at 1500°C have revealed dislocation networks in which the ½〈110〉 dislocations are extended by climb into ¼〈110〉 collinear partials. Dislocation nodes of two types are found, both of the form ½[110] + ½[101] + ½[110] = 0. One configuration (type I) forms by climb dissociation and contains two partial modes of the form ¼[110] +...