Crack deflection at a transcrystalline junction

Using a model polypropylene-based composite, we report the observation of longitudinal damage in a transcrystalline interphase under the effect of a transverse notch, propagating in a direction perpendicular to the axis of a Kevlar fiber. We find that a Cook–Gordon-like damage mechanism is active. The damage growth rate in the transcrystalline layer, parallel to the fiber axis, is larger in thinner layers. A schematic model of the microstructural aspects of damage, which reflects the anisotropic microstructure of the transcrystalline layer, is proposed and briefly discussed.