EELFS study of the cementite local atomic structure

The changes in the nearest - neighbour surroundings of carbon atoms in the cementite Fe₃C lattice due to the heat treatment are analysed by the Extended Energy Loss Fine Structure (EELFS) method. To study the local atomic structure of the carbon steel U15 after different heat treatment regimes the electron energy - loss spectra above the C K edge and Fe L_2,3 edge were measured. The measured experimental EELFS spectra were treated by the standard for the Extended X - ray Absorption Fine Structure method procedure using Fourier transformation to obtain the parameters of the nearest - neighbour atomic surroundings. Qualitatively the assumption was made that the number of the iron atoms in the carbon atom nearest - neighbour surroundings changes due to the heat treatment, the evidence of which was the change in the ratio of the first two feature intensities of the atomic radial distribution function. This assumption is consistent well with the previous Mössbauer data.