TEM characterization of precipitates in the segregated regions of a low-carbon, low-manganese, titanium-added steel

A concentric solidification technique has been employedto simulate sulphide precipitation at the centreline of acontinuously cast low-carbon, low-manganese, titaniumaddedsteel slab. Selected precipitates were identifiedusing transmission electron microscopy following samplepreparation by focused ion beam milling techniques. FeTiS2and hexagonal MnS containing iron atoms form in closeproximity to each other in super-saturated areas of theconcentrically solidified sample. The presence of FeTiS2precipitates in low-carbon steel has been verified for thefirst time, and the crystal structure determined by electrondiffraction analysis as a trigonal CdI2-type with a P3m1 spacegroup and lattice parameters of a = 0.341 nm and c = 0.569nm.