The effect of stress state on the ductility and the critical extent of void growth in nodular cast iron

Abstract

In the present studies the test materials are nodular cast irons composed of a ferritic matrix and spherical graphite nodules with different size distributions. A series of circumferentially notched tensile specimens are used to determine the effect of the stress state on the ductility and the critical extent of void growth at failure initiation. Size parameters describing the change in microstructure of test materials are measured in ductile rupture. Based on the theoretical Rice-Tracey model, the experimental results give the macroscopic and the microscopic parameters describing the fracture ductility of materials and critical extent of void growth in ductile failure. Moreover, a criterion of void coalescence is briefly discussed. © 1992.