Orientation relationship between a ferritic matrix and κ-phase (Fe3AlCx) precipitates formed during metal dusting of Fe-15Al

An Fe-15 at.% Al alloy has been exposed to a strongly carburising CO-H2-H2O gas mixture under metal dusting conditions. Cementite (Fe3C) was detected to be present only in the coke which is a reaction product of the high-temperature corrosion metal dusting. Needle- or plate-like κ-phase (Fe3AlCx) precipitates close to the surface were identified by means of electron back-scattered diffraction (EBSD). EBSD analyses of several precipitates and neighboured matrix areas indicate a Nishiyama-Wassermann orientation relationship between the κ-phase precipitates and the α-Fe(Al) matrix.