Effect of heat treatment on the local atomic structure of cementite Fe3C in steel

The extended energy-loss fine structure (EELFS) spectroscopy was used to an alyze the response of the nearest neighborhood of carbon atoms in the latti ce of cementite Fe3C to heat treatment. For the study of the local atomic s tructure of the U15 steel after different heat treatments, the electron ene rgy loss spectra were obtained beyond the carbon K edge. The experimental E ELFS spectra were treated by the standard technique employed for processing EXAFS (extended X-ray absorption fine structure) spectra, i.e., using the Fourier transformation for determining the parameters of the nearest atomic neighborhood. A qualitative conclusion was made that heat treatment affect s the number of iron atoms in the nearest neighborhood of carbon atoms in c ementite. This conclusion is based on the changes in the ratio between the intensities of two first maxima of the radial atom distribution functions a nd is consistent with Mossbauer data.