XENON EMISSION ACCOMPANYING FRACTURE OF XENON-IMPLANTED CUBIC ZIRCONIA

The emission of xenon following the fracture of xenon-implanted cubic zirconia has been studied using mass spectrometry. All samples showed intense Xe bursts at failure. Order of magnitude estimates of the amou nt of Xe released suggest that micrometer-scale regions of the tensile surface on either side of the fracture surface of these samples do no t show sufficient damage to account for this emission. However, SEM mi crographs of the fracture surface show evidence for extensive microcra cking immediately adjacent to the tensile surface. It is believed that these microcracks are formed when the advancing crack encounters the tensile stresses immediately below the Xe-implanted surface layer and disrupts the Xe inclusions produced by implantation. Some samples also show Xe bursts prior to failure; SEM observations of these samples sh ow shallow conchoidal cracks on the tensile surface, which apparently form during loading and would account for the release of Xe prior to f ailure.