Effects of ion implantation on the mechanical properties of fully and partially stabilized zirconias

Indentation testing methods were used to induce localized plasticity and fracture in a range of fully and partially stabilized zirconia specimens before and after implantation with 400 keV Ti/sup +/ ions (400 keV = 6.4088x10/sup -14/ J). Peak Knoop microhardness occurred at a dose of approx. =4x10/sup 16/ ions cm/sup -2/. The critical energy density for amorphization was estimated to be 64 kJ mm/sup -3/. The apparent indentation fracture toughness of fully stabilized zirconia increased after implantation; in contrast, partially stabilized zirconia and tetragonal zirconia polycrystal specimens showed increases in the frequency and extent of cracking after implantation. Reflected light microscopy and interferometry indicate that, after implantation, suppression of the transformation toughening mechanism occurs in these materials.