Elucidation of the solidification sequence of a complex graphitic HSS alloy under a combined approach of DTA and EBSD analyses

In this work, a complex Graphitic High Speed Steel (Gr-HSS) obtained from a spin casting process that allows high cooling rates during solidification is considered. Differential Thermal Analysis is carried out at a moderate and constant heating scan speed until complete remelting. This allows to link each of the peaks observed in the DTA curve to a related phase transformation that had occurred during the initial solidification in the spin casting process. The phases which were formed during the spin casting process, especially solidification carbides, are characterized through light microscopy (distribution), scanning electron microscopy (morphology) either associated with EDS (chemical composition), or associated with EBSD (crystal lattice identification). A discussion is opened about the influence of solidification rates on both supersaturation and lattice distortions in the solidification carbides. The combination of reverse DTA analysis and SEM/EDS-EBSD applied here to the complex Gr-HSS alloy constitutes a relevant approach to understand the phase transformations during complex casting processes where relatively high solidification rates are achieved.