Effect of grain size on superplastic behavior of Al2O3/YTZ

Grain size strongly influences the superplastic properties of a fine-grained, 20 wt.% Al2O3-reinforced, Y2O3-stabilized tetragonal ZrO2 (Al2O3/YTZ). The elongation to failure of the material decreases, and the flow strength increases, with increasing grain size. The flow stress at a constant true strain rate and at a given strain is proportional to the grain size raised to a 0.75 power. As a result, the superplastic deformation rate in Al2O3/YTZ is inversely proportional to the grain size raised to a 1.5 power.