Stage-II fatigue crack growth model from 3D dislocation dynamics simulations

Stage-II fatigue crack propagation in FCC metals is investigated using 3D discrete dislocation dynamics (DD) simulations. The calculations show that dislocation/grain–boundary interaction affects slip dispersion everywhere the grain, including tip region. results are analysed and drawn form of simple, quantitative mathematical expressions, depending on a set physical variables. This approach helps developing comprehensive model, where growth rate da/dN depends both opening displacements tip-related nucleation nano-cavities. It shown modelled response compatible with well-known Paris expression, which we further interpreted as ratio between energy stored region over spent extending surfaces. model validity finally evaluated by comparison relevant experimental evidence.