| Alumina is known to be a brittle substance; however, recently it has been shown that
deformation in the nature of dislocations could be introduced by scratching, milling, diamond
indentation etc. The effective deformation produced in alumina particles particularly by ball
milling is discussed. It is shown that on annealing such particles, the deformation is relieved by
a process of recovery phenomenological to the annealing of a ductile metal. A two stage
recovery process (primary and secondary) was identified and activation energies of the order of
15.64 and 27.4 Kcal/mole respectively were measured. The behm•iour was analysed considering
the hexagonal structure of an alumina crystal. |
