Journal of the American Ceramic Society, Vol.102, No.3, 1373-1378, 2019
A model of crack healing of glass by viscous flow at elevated temperatures
The crack healing in glass occurs by viscous flow driven by surface tension at temperatures higher than the glass transition. The Vickers-induced radial crack on glass surface is modeled using an oblate spheroid, where the major axis length is the crack length and the minor axis length is the crack opening displacement (COD). The finite element simulation showed that the crack length decreased approximately linearly with time. The recovery time, which was required to shrink to a quarter of the initial length, was proportional to the viscosity and the initial length, and inversely proportional to the surface energy. The recovery occurred faster with decreasing COD. The crack blunting took place also for very sharp cracks. Experimentally derived master curve of crack healing could be explained by the present simulation model fairly well.