Abstract
Several cast irons, prepared with different chemical compositions and microstructures have been examined by extensive mechanical testing and optical and scanning electron microscopy (SEM). Properties arising from various microstructures are tabulated. Mechanical properties are shown to be a function of both the martix and graphite (or carbide) forms. Changing the matrix from ferritic-pearlitic to bainitic-martensitic type results in effects similar to those experienced in steels containing these phases respectively. The influence of graphite (or carbides) on the final properties, however, is dictated by the respective shapes and distributions of these microstractural constituents. The coupled zone-eutectic region in gray cast iron is asymmertical and inclined to the right-hand side in Fe-C equilibrium phase diagram. Consequently, hypereutectic compositions reveal denderites of primary austenite. In white cast iron, the coupled zone symmetry is thought to arise from the high volume fraction of cementite which compensates for its growth rate anisotropy.