Fatigue strength model based on microstructures and damage mechanism of compacted graphite iron

The as-casted compacted graphite irons (CGIs) with different microstructures were opted to investigate the relation between tensile and fatigue strengths as well as the correspondingly influencing mechanisms. The results show that the fatigue strength increases first and then decreases with increasing the tensile strength. The fatigue strength is mainly determined by the area percentage ratio of ferrite to graphite and the strength of ferrite, while the tensile strength is basically dominated by the pearlite area percentage, resulting in the non-synchronous relation above. Finally, based on these investigations, a prediction model for the fatigue strength of CGI is proposed.