Sub-Critical Crack Growth in Oxide Glasses

International audienceMaterial degradation due to everyday wear and tear, sand storms, external irradiations, extreme temperatures, humidity… is a legitimate concern of many engineers when developing devices and systems. These types of damages can lead to premature failure, which requires an investment of additional energy recourses for reparations or replacements. Oxide glasses are not exempt from these concerns. Rather, when considering components of solar panels and portable electronic devices, lenses, containment vessels for nuclear waste management… or even safeguarding valuable glass museum pieces, avoiding premature failure is a relevant concern. Frequently, post-mortem failure studies reveal material flaws, which were propagating via sub-critical crack growth.Sub-critical crack growth concerns the slow growth of crack fronts and flaws when the stress intensity factor is less than the fracture toughness. Environmental factors, including temperature and humidity, actually aid in crack front growth. Hence, literature frequently coins this sub-critical crack growth as stress corrosion cracking. The presentation will review key details concerning stress corrosion cracking. Nevertheless, it is less predictable concerning how the chemical composition of a glass alters the stress corrosion cracking behavior. Recent studies concerning SiO2-B2O3-Na2O ternary glass systems take a holistic viewpoint of how materials break. The novel parameter coined the depolymerization index from these studies unveiled mesoscale changes. Additional, it provides surprising trends with the stress corrosion cracking behavior in Region I. The presentation will focus on these aspects of stress corrosion cracking