The micro - mechanisms of failure of nodular cast iron

The contribution deals with a comparison of the micro - mechani sms of failure of nodular cast irons at static, impact and fatigue stress . Several specimens of ferrite - pearlitic nodular cast irons with different content of ferrite in a matrix were used for metallographic analysis, mechanical tests and micro - fractographic analysis. Mech anical properties were found by static tensile test, impact bending test and fatigue tests. The micro - fractographic analysis was made with use of scanning electron microscope VEGA II LMU on fracture surfaces of the specimens fra ctured by these mechanical and fatigue tests. Fracture surfaces of analysed specimens are characteristic of mixed mode of fracture. Micro - mechanism of failure of nodula r cast irons is dependent on the method of stress .