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

A concentric solidification technique has been employed to simulate sulphide precipitation at the centreline of a continuously cast low-carbon, low-manganese, titanium-added steel slab. Selected precipitates were identified using transmission electron microscopy following sample preparation by focused ion beam milling techniques. FeTiS(2) and hexagonal MnS containing iron atoms form in close proximity to each other in super-saturated areas of the concentrically solidified sample. The presence of FeTiS(2) precipitates in low-carbon steel has been verified for the first time, and the crystal structure determined by electron diffraction analysis as a trigonal CdI(2)-type with a P3 m1 space group and lattice parameters of a= 0.341 nm and c= 0.569 nm.