Comparison of the low-cycle and medium-cycle fatigue behaviour of ferritic, pearlitic, isothermed and austempered ductile irons

In this paper, the fatigue behaviour of some ductile irons for structural applications is analysed in terms of strain–life, stress–life and cyclic stress–strain curves. Push–pull, strain-controlled fatigue tests were carried out on ferritic, pearlitic, isothermed and austempered ductile irons.The same tests were executed on a structural steel for comparison purposes. The experimental data were processed according to the common practice as well as to a recent procedure proposed by the authors, which ensures the compatibility conditions are satisfied in a strict sense. Conversely, if the common practice is applied, compatibility conditions are satisfied only approximately. Finally, the results of the experimental fatigue tests on the different materials are compared and discussed in view of application to structural components.