Work of Fracture and Crack Healing in Glass

Abstract

The work of fracture, γwoF, of a soda‐lime‐silica glass was determined as 5.5 J/m 2 in an inert atmosphere and 4.4 J/m 2 in air by using a short bar specimen with a chevron notch. The critical stress intensity factor K IC calculated from γ wof obtained in an inert atmosphere agreed with the value, 0.88 MN/m 3/2 , determined by the indentation method. In unloading‐loading cycles during stable crack growth, crack healing was observed both on the diagram of load vs load‐point displacement and visually. Crack healing is more prevalent in an inert atmosphere, occurring only minimally in air. The energy for healing was measured as 0.65 J/m 2 in an inert atmosphere and ∼0.21 J/m 2 in air.