A Mixed-Mode Crack-Growth and Fracture Model for Field-Assisted Ion-Exchanged Glass

It is suggested that shear forces from the compression layer during field-assisted ion exchange of glass cause stable growth of preexisting flaws when the advancing ion-exchanged layer approaches the flaw tip. A quantitative model is presented which explains most of the previously puzzling experimental results, even though it ignores the change in crack direction required if the maximum tensile stress criterion is appropriate for fracture.