M\"ossbauer spectroscopy of short-range ordered Fe-Cr alloys

TL;DR

This paper introduces a new direct method to analyze Mössbauer spectroscopy data for short-range order in Fe-Cr alloys, addressing previous discrepancies with neutron scattering results and improving understanding of alloy phase stability.

Contribution

A novel direct analysis technique for Mössbauer spectra of Fe-Cr alloys is developed and validated, enhancing the accuracy of SRO parameter determination.

Findings

Good agreement with neutron scattering at low Cr concentrations

Discrepancies remain at higher Cr concentrations

Method verified with synthetic spectra

Abstract

Short-range ordering (SRO) in Fe-Cr has been the subject of a number of recent experimental and theoretical investigations, as ordering effects are significant for the phase stability of this technologically important alloy. Recently, discrepancies regarding the SRO behavior of Fe-Cr have been reported between results obtained with M\"ossbauer spectroscopy and diffuse neutron scattering, respectively. As the methodology for reducing SRO parameters from M\"ossbauer spectra is indirect and relies on the determination of a large number of parameters, here a new method for directly connecting the M\"ossbauer effect with SRO is presented. The method is verified using synthetic spectra derived from Monte-Carlo simulated alloy structures with different SRO parameters and subsequently it is applied to experimental data obtained from Fe-Cr alloys. Agreement with diffuse neutron scattering is found at low Cr concentrations; however, some discrepancies still remain for more concentrated alloys and possible reasons for these are discussed.