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 linking 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 that were formed during the spin-casting process, especially solidification carbides, are characterized through light microscopy (distribution) and 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 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. Graphic abstract