Crack Blunting of High‐Silica Glass

The mechanical strength of abraded high‐silica glass was measured after immersion in water and silicic acid solution at room temperature and 88°C. The strength increase was observed at 88°C. This phenomenon is usually explained by crack blunting. From an observation of the dissolution rate of a porous glass with a similar composition and a comparison of the strength increase in water and silicic acid, it was concluded that the dissolution and subsequent precipitation of the high–silica glass is the mechanism of the crack blunting.