Effect of ferritic microstructure on local damage zone distance associated with fracture near notch

A deterministic approach is used to analyze cleavage failure near the notch root by application of a local fracture criterion. Micromechanism of fracture is assessed using finite element calculations. Two ferritic microstructures have been selected; they differ significantly in the carbide thickness as the fracture data scattered widely. Local damage zones are calculated from the normal stress distributions and compared with those from the notch root to the location of failure initiation. To this end, the static three-point bend Charpy V-notch specimens were used. Microfractography identifies the local damage zone distances and their locations with reference to the prevailing microstructures.