Modeling Slow Crack Growth Behavior of Glass Strengthened by a Subcritical Tensile Stress Using Surface Stress Relaxation

Glasses exhibit slow crack growth under stress intensities below the fracture toughness in the presence of water vapor or liquid water. It has been observed by several authors that when an oxide glass with a large crack is held under a subcritical stress intensity (where no slow crack growth occurs)...

Full description

Saved in:
Bibliographic Details
Published in:Journal of the American Ceramic Society 2015-10, Vol.98 (10), p.3075-3086
Main Authors: Seaman, Jared H., Lezzi, Peter J., Blanchet, Thierry A., Tomozawa, Minoru
Format: Article
Language:English
Subjects:
Compressive properties
Compressive strength
Crack arrest
Crack propagation
Diffusion
Dissolution
Fracture mechanics
Fracture toughness
Glass
Glass fibers
Molecular chains
Stress intensity
Stress relaxation
Tensile stress
Water
Water vapor
Citations: Items that this one cites
Items that cite this one
Online Access:Get full text
Tags: Add Tag
No Tags, Be the first to tag this record!
Description
Summary:Glasses exhibit slow crack growth under stress intensities below the fracture toughness in the presence of water vapor or liquid water. It has been observed by several authors that when an oxide glass with a large crack is held under a subcritical stress intensity (where no slow crack growth occurs) in room‐temperature water vapor or liquid water, upon reloading to a higher stress intensity, a finite restart time is observed prior to measurable crack extension. This phenomenon of apparent strengthening, or crack arrest, has been attributed to concepts such as corrosive dissolution of the crack tip, crack tip blunting, or water diffusion, and subsequent swelling of the material around the crack tip. Recently, a newly observed surface stress relaxation process that is aided by molecular water diffusion was used to improve the mechanical strength of glass fibers and to explain the subsurface compressive stress peak observed in ion‐exchange strengthened glasses. The same process is employed here to explain these delayed slow crack growth data. A simple mathematical model has been developed utilizing water‐assisted surface stress relaxation and fracture mechanics. Predictions of restart times using the model agreed well with published experimental data, indicating that surface stress relaxation is responsible for the anomalous delayed slow crack growth behavior.
ISSN:0002-7820
1551-2916
DOI:10.1111/jace.13710