A novel microstructure – Grain boundary character based integrated modeling approach of intergranular stress corrosion crack propagation in polycrystalline materials

A novel integrated modeling approach, using Markov Chain theory, Voronoi algorithm for microstructure construction, and Monte Carlo simulations, has been presented in order to predict the intergranular stress corrosion cracking (IGSCC) behaviour in polycrystalline materials. The model takes both the physical microstructural features, such as the grain size distribution and grain shape, as well as the grain boundary character distribution (GBCD) and their orientation with respect to the external stress axis into account. Besides, several characteristic features of IGSCC such as, crack-branching and coalescence, multiple crack-nucleation sites, and crack-turn have been incorporated in the model. The predicted crack-propagation behaviour is in reasonable agreement with the electron back-scattered diffraction (EBSD) based experimentally determined relationship between the GBCD and 2D crack-percolation frequency of API 5L X65 pipeline steel.