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.