Temperature dependence of the three-point bending fracture behavior of soda–lime–silica glass with surface scratch

• The fracture behavior of soda–lime–silica glass had been studied via three-point bending.
• The fracture strength of glass at an elevated temperature was measured.
• The fracture toughness of glass at an elevated temperature was determined.
• The sensitivity of the fracture strength to surface scratch was analyzed.

The fracture behavior of soda–lime–silica glass was investigated via three-point bending test at different temperatures ranging from room temperature to 650 °C with two types of specimens: one with artificial scratch and the other intact. The bending fracture strength and fracture toughness at elevated temperatures were measured and analyzed. The fracture toughness of the glass increased fast in the vicinity of brittle to ductile transition temperature and then decreased afterwards; no fracture occurred at higher temperatures. In addition, the sensitivity of the fracture strength to surface scratch was analyzed using the ratio of the average bending fracture strength of the glass specimens with surface scratch to the average bending fracture strength of the ones without surface scratch; the result showed that the use of soda–lime–silica glass components with surface damage is very dangerous at the temperature in brittle range, especially around 300 °C, at which the crack growth resistance did not increase. Furthermore, the three-point bending test with the specimen containing surface scratch was an easy and convenient way to determine the fracture toughness of glass at elevated temperatures.