Compositional dependence of hardness of (Ce,Y)-TZP/Al2O3 composites

Vickers hardness testing was conducted on a series of (Ce,Y)-TZP/Al2O3 composites with different nominal chemical compositions in the applied load range from 4.9 to 49 N. The measured hardness was observed to increase with increasing indentation load for all of the composite samples. The load-independent hardnesses of the composites were determined based on the analyses of the indentation data according to the modified proportional specimen resistance model. The compositional dependence of the resultant load-independent hardness was analyzed and it was shown that, if the effect of grain size on the hardness of each phase in the composites is considered properly, the hardness of the composites would meet the conventional rule of mixture.