Influence of Composition on Fatigue Behavior and Threshold Stress Intensity Factor of Borosilicate Glasses

Fatigue behavior of borosilicate glasses was studied using the analysis of subcritical propagation of Vickers indentation cracks. Glasses containing various amounts of glass-network modifiers, mainly soda, were considered. Cone and median/radial crack systems were observed, depending on glass composition, indenter geometry, and test environment. Indentation tests were performed in water, holding the maximum load for durations ranging from 15 s to 6 d. The analysis of the crack length as a function of dwell time allowed evaluation of the subcritical growth parameters and fatigue limit at crack arrest. The influence of composition on fatigue parameters and fatigue limit was discussed in terms of fourfold-coordinated boron atoms fraction compared with the content of glass-network modifier ions.