GRAIN-GROWTH ENHANCEMENT IN ALUMINA DURING HOT ISOSTATIC PRESSING

HIP experiments carried out on pure alumina show that grain growth is enhanced both during and after the densification process. These results are compared with those published in the literature on several superplastic ceramics and metals, and a general phenomenological model for grain growth enhancement is proposed. This model is used to simulate grain size gradients generated during the HIP densification of a complex part. TEM examination of the samples shows that point defects and dislocation loops are responsible for grain growth enhancement.