Mechanical properties of silicate glasses as a function of composition

Bulk production of silicate glasses is based around a narrow range of soda–lime–silica compositions and as a result any variation in mechanical properties with composition is normally considered to be of little interest. However, studies by a range of authors over the last 50 years or so have demonstrated some intriguing variations of properties such as toughness, brittleness and, more controversially, strength with composition. We have produced several series of alkali-mixed alkaline earth-silicate glasses and are assessing the variation of their mechanical properties with composition using both conventional indentation and nanoindentation. The nanoindentation studies are also being used to assess the effects of surface hydration on the near surface mechanical properties of these glasses. This presentation reviews the results we have obtained to date and attempts to draw out some wider conclusions concerning the compositional dependences of the mechanical properties of silicate glasses.