A Methodology for Assessing Short Fatigue Crack Growth in DCI Materials Affected by Intergranular Embrittlement at Temperatures Nearby 400 °C

A crack growth model for assessing the lifetime and short fatigue crack growth of ductile cast iron materials is proposed. The model bases on the assumption that the crack advance per cycle correlates with the cyclic crack tip opening displacement. Intergranular embrittlement at medium temperatures is accounted for as a temperature and strain rate dependent crack accelerating mechanism. The model is calibrated and successfully applied to predict temperature dependent fatigue lifetime and short crack growth of a ductile cast iron material.