Experiments concerning the morphology of fracture surfaces of various materials are reviewed. The observations are interpreted within the framework of models of lines moving in a random environment. This suggests that fracture of heterogeneous materials could be seen as a dynamic phase transition.

Different rupture modes and different fracture toughness values were obtained on an aluminium alloy subjected to four different heat treatments. The correlation functions of the bidimensional cuts of the four fractured surfaces were determined. It was found that these surfaces were fractal, and that their fractal dimensions were identical, within experimental error.

We report in situ atomic force microscopy experiments which reveal the presence of nanoscale damage cavities ahead of a stress-corrosion crack tip in glass. Their presence might explain the departure from linear elasticity observed in the vicinity of a crack tip in glass. Such a ductile fracture mechanism, widely observed in the case of metallic materials at the micrometer scale, might be also at the origin of the striking similarity of the morphologies of fracture surfaces of glass and metallic alloys at different length scales.

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