Indentation grid analysis of nanoindentation bulk and in situ properties of ceramic phases

The in-situ and bulk mechanical properties of ceramics materials and particulate composites have been estimated by nanoindentation tests. The values of Young's modulus and hardness of the composites constituent phases were evaluated both by SEM imaging and by a probabilistic approach (Indentation Grid). It was observed that the in-situ mechanical properties were different from the bulk properties in most cases even if the differences were generally not very large. Indentation grid (IG) was used to evaluate the in situ properties of the ceramic phases. It was shown that IG can be considered a valuable tool in order to efficiently extract properties from composites if the indentation length is appropriately scaled to the microstructural dimension. In the tested particulate ceramic composites, it was in fact shown that both hardness and Young's modulus of the secondary phases were not influenced by the neighbouring matrix. Some discrepancies were observed between the results obtained by IG analysis and those obtained by the more traditional SEM analysis.