Structural peculiarities of plastically-deformed cementite and their influence on magnetic characteristics and Mossbauer parameters

TL;DR

This study uses first-principles calculations and Mossbauer spectroscopy simulations to explore how different carbon atom positions in cementite affect its magnetic and Mossbauer properties, especially after annealing.

Contribution

It introduces a detailed analysis of carbon atom positions in cementite and their influence on magnetic and Mossbauer parameters, highlighting subtle detection methods.

Findings

Different carbon positions influence Mossbauer spectra features.

Detection of carbon position change is possible through detailed MS analysis below Curie temperature.

Subtle MS line details reveal carbon atom environment changes.

Abstract

Cementite Fe3C is studied with first-principles calculations. Two possible positions of carbon atoms in the iron sublattice are considered: with prismatic or octahedral environment. Mossbauer spectra (MS) with parameters calculated for both modifications are simulated above and below the Curie temperature. A possibility to detect the change in carbon position upon annealing from MS is discussed. It is shown that this is hardly possible using a standard approach to treatment of MS, but it can be seen in more subtle details of the MS below the Curie temperature, such as widths and positions of separate lines.