Cavitation damage mechanisms in a superplastic zirconia(3Y-TZP)

Cavitation damage in a fine-grained 3Y-TZP is examined by constant-stress tensile creep tests. The most of damage volume is shown to occur from micrometer-sized cavities occupying less than several percents of the total cavity population. On the basis of a damage accumulation model derived from the analysis of cavity size distributions, the strain dependence of the damage evolution is shown to arise from the plastic growth law of the micrometer-sized cavities. The stress dependence of the damage is also revealed to originate from the stress dependence of their formation rates, but not directly from the total cavity nucleation rates.