Topological and metric properties of microscopic crack patterns: application to thermal fatigue of high temperature tool steels

Sabine Le Roux (1) , Farhad Rezai-Aria (1)

1 ICA - Institut Clément Ader

The topological properties of heat‐checking patterns, produced on the oxidized surface of high temperature tool steels under thermal fatigue experiments, are investigated using image analysis methods. All crack networks are composed of polygonal cells with a mean number of sides close to 6. Whatever the thermal cycling conditions, the semi‐empirical Aboav‐Weaire's and Lewis' laws are quite well verified. The least‐squares fit parameters of these laws are discussed and compared with values reported in the literature for other random cellular structures. It is shown that the heat‐checking cells undergo a strong shrinkage and that the cellular organization is rather disordered at the beginning of the fragmentation process. The heat‐checking networks evolve towards a more stable and ordered state upon cycling. Most disordered cellular networks are obtained at low maximal temperatures and low heating rates. The slope of Lewis' law is mainly dependent on the maximum heat‐flux density applied to the specimen during the heating period. Whatever the test conditions, the stabilized heat‐checking networks obey a unique normalized Lewis' law.

Domaines: Sciences de l'ingénieur [physics]

Sabine Le Roux, Farhad Rezai-Aria. Topological and metric properties of microscopic crack patterns: application to thermal fatigue of high temperature tool steels. Journal of Physics D: Applied Physics, 2013, 46 (29), ⟨10.1088/0022-3727/46/29/295301⟩. ⟨hal-01666696⟩