Analysis of stress triaxiality influence: ferritic DCI damaging micromechanisms

Ductile cast irons are characterized by an interesting mechanical properties combination (high ductility, high tensile strength, good wear resistance). Graphite nodules morphological peculiarities and matrix microstructure (both chemical composition and heat treatment controlled) strongly affect the mechanical behaviour and the damaging micromechanisms, also considering very simple loading conditions (e.g. tensile test conditions). Focusing ferritic ductile irons, matrix - graphite nodule debonding is often identified as the main damaging micromechanism, and numerous studies provided analytical laws to describe growth of a single void, depending on the void geometries and matrix behaviour. In this work, ferritic DCI damaging micromechanisms were investigated, under uniaxial tensile tests, considering the triaxiality influence.