Application of high-pressure torsion for consolidation of ceramic powders

Alumina (α-Al2O3) powders were successfully consolidated by application of high-pressure torsion (HPT) at ambient temperature and by a subsequent annealing process. Introduction of strain by HPT was confirmed by peak broadening in X-ray diffraction analysis. It was shown that consolidation was greater, giving rise to increased hardness with increasing imposed strain, annealing temperature and annealing time. Scanning electron microscopy showed that consolidation occurred at lower temperatures due to the presence of strain.