Application of atomic force microscopy in determining the fractal dimension of the mirror, mist, and hackle region of silica glass

Fractal analysis has been used as a method to study fracture surfaces of brittle materials. However, it has not been determined if the fractal characteristics of brittle materials is consistent throughout the fracture surface. Therefore, the fractal dimensional increment of the mirror, mist, and hackle regions of the fracture surface of silica glass was determined using atomic force microscopy. The fractal dimensional increment of the mirror region (0.17–0.26) was determined to be statistically greater than that for the mist (0.08–0.12) and hackle (0.08–0.13) regions. It is thought that the increase in the fractal dimensional increment is caused by a greater tortuosity in the mirror region due to, most likely, the slower crack velocity of the propagating crack in that region and that there is a point between the mirror and mist region at which the fractal dimension decreases and becomes constant.

Research Highlights
► The fracture surface of silica glass does not have a constant fractal dimension.
► Mirror region has greater fractal dimension than mist or hackle region.
► Fractal dimension decreases between mirror and mist region.
► Greater fractal dimension could be due to slower crack velocity in mirror region.