The topology of surfaces formed by subcritical crack growth was investigated by the method of mapping using atomic force microscopy. The objective of the study was to determine how well the upper and lower surfaces matched after they have been formed by a crack moving at a slow velocity. Specifically, are features left in the fracture surfaces of silicate glasses that would indicate the formation of cavities during the fracture process? Studies were carried out on silica glass and soda-lime-silicate glass. Fracture surfaces were formed either in water or in moist environments at velocities that ranged from 10-11 m/s to 10-3 m/s. This procedure covered almost the entire range of velocities used in subcritical crack growth experiments in glass. Fracture surfaces formed during our studies were found to match over the entire range of velocities and for all environments studied. Normal to the fracture surface, the surfaces matched to an accuracy of better than 1 nm; horizontal to the fracture plane, the match was better than 5 nm. Within these limits, no evidence for cavitation within the fracture surface was found. The data obtained in this study was compared with results from other atomic force microscopy studies and with the results of molecular dynamics simulations.
Citation: International Conference on Fracture
Pub Type: Journals
atomic force microscopy, fractography, fracture, glass, subcritical crack growth