Abstract
Austempered ductile iron (ADI) is a material with a wide range of potential application, especially in the automotive and earth moving machinery industries. Cast components usually subjected to variable dynamic loading may fail by sudden, unexpected fatigue fractures. Thus, fatigue crack propagation resistance is one of the most important material properties. The aim of this contribution is to determine the fatigue crack propagation curve da/dN vs. Ka and the threshold amplitude of stress intensity factor Kath. Microstructure and its influence on crack initiation and propagation is analyzed. A diversity of crack propagation modes at low Ka and high Ka was observed.