LIMITING SUBCRITICAL CRACK-GROWTH IN GLASS-MATRIX COMPOSITES

Subcritical crack growth measurements were made in borosilicate glass/Fe-Ni-Co particulate composites, in which the metal particles were used both as-received and also with a surface oxidation treatment. No crack growth was observed in the composites containing the partially oxidized particles before catastrophic failure ensued. The composites containing nonoxidized particles did exhibit measurable growth. Fracture surface observations identify strong bonding between the particles and matrix as the main reason for significantly increasing the slow crack growth resistance. This method of "effectively" eliminating subcritical crack growth may be a means by which the design threshold of glasses is raised, thus opening new areas of applications for glass systems.