A Transmission-Electron-Microscopy Study of the Substructure of High-Purity Pearlite

Using transmission electron microscopy, many of the substructural faults of pearlite colonies were identified and characterized. It was found that a ferrite subgrain boundary can affect the growth of a cementite lamella depending upon the orientation of the boundary with respect to the growth direction of the lamella. Other substructural features found were: dislocations at the cementite-ferrite interface, discontinuities in cementite lamellae containing a high density of dislocations, and growth steps in cementite lamellae. The observed phenomena are discussed in terms of the origin of dislocations and substructural faults in a growing pearlite colony.