Characterization of dislocation structures around a mixed-mode fatigue crack tip in a single-crystalline iron–silicon alloy

Dislocation structures around a mixed-mode fatigue crack tip introduced into a single-crystalline iron–silicon alloy is characterized by cross-sectional electron backscatter diffraction and high-voltage electron microscopy. The results show that the crack growth is preceded by the formation of a cell band and the crack grows along cell boundaries. Crack growth rate and width of the cell band are constant despite the monotonic increase in stress intensity, which is anomalous in terms of the conventional fracture mechanics concept.