Abstract
The crack of fatigue fracture of nodular graphite cast iron selects most fragile region of material to propagate. The 3D characteristics of microstructure and crack propagation path were studied by a serial sectioning method. Nodular graphite cast irons with two kinds of pearlite volume fraction were continuously polished and etched with nital under an optical microscope. The fatigue crack is found to propagate through ferrite-graphite interface preferentially. Hence, size and distribution of graphite particle should be controlled to increase the fatigue propagation resistance.
