1/28/2024 0 Comments Silica glass![]() Further analysis of the correlations between these local properties allows to obtain a better microscopic understanding of the deformation and fracture of oxide glasses and how the local heating close to the crack tip, up to several hundred degrees, permits the structure to relax. Ultra-Low thermal expansion (ULE) silica glass with essentially zero coefficient of thermal expansion is one of the most promising achievements in glass technology in a few decades. Silica-glass fabrics have excellent chemical resistance and electrical insulation properties. Before fracture occurs, the local composition, structure, and mechanical properties are heterogeneous in space and show a strong dependence on the applied strain. We find that during the fracture of Na-rich glasses very irregular cavities as large as 3–4 nm form ahead of the crack front, indicating the presence of nanoductility in these glasses. Glass can be made from pure silica, but quartz glass (also referred as quartz) has a high glass transition point at around 1200☌, which makes it difficult to form into panes or bottles. A strong composition dependence is also seen in the crack velocity which, for the strain rate considered, is on the order of 1800 m/s for glasses with low Na concentration and decreases to 650 m/s if the concentration is high. ![]() The stress-strain curves demonstrate that silica glass is brittle whereas the glasses rich in Na show pronounced ductility. We use large-scale simulations to investigate the dynamic fracture of silica and sodium-silicate glasses under uniaxial tension.
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