New insights into crystallographic correlations between ferrite and cementite in lamellar eutectoid structures, obtained by SEM-FEG/EBSD and an indirect two-trace method

Four different ferrite/cementite orientation relationships (ORs) in near-eutectoid steel are derived using SEM-FEG/EBSD (scanning electron microscopy-field emission gun/electron back-scatter diffraction) and an indirect two-trace method. They show a common feature of close-packed plane parallelism between ferrite and cementite. Their crystallographic compatibility with habit planes shows a variety of possible habit planes and excludes the existence of the exact conventional Bagaryatsky and Pitsch-Petch ORs. Each of these new ferrite/cementite ORs is correlated with a different edge-to-edge matching condition between austenite and pearlitic ferrite, and between austenite and pearlitic cementite, and possesses specific morphological features. The present results may give deep insight into the crystallography of pearlitic transformation and provide useful information for materials design through interface tailoring in steels.