Cavity Damage Accumulation in Alumina Doped with Zirconia or Magnesia

摘要

For an initial grain size of 1.0 μm, the accumulation of damage volume in a ZrO_2-dispersed alumina is shown to proceed more slowly than that in a MgO-doped alumina under a given loading condition, irrespective of higher tensile flow stress in the former than in the latter. The slower damage accumulation in the ZrO_2-dispersed alumina is caused from the slower formation and growth of cavities larger than the initial grain size. Such slower cavitation is also shown to delay the onset of microcracking. The delayed microcracking leads to higher tensile ductility in the ZrO_2-doped material than in the MgO-doped one.