Mossbauer spectroscopic and XRD studies of two 1-Fe2Al5 intermetallics

Two intermetallic FeAl compounds with Al content of 70.68 and 72.17 at% were studied using Mo & uml;ssbauer spectroscopy (5-296 K) and X-ray diffraction (15-300 K). The compounds were found to crystallize in the orthorhombic Cmcm space group (1-phase). The collected data revealed that dynamics of the Fe atoms (harmonic in entire temperature range) is significantly different that Al atoms. For the latter strong anharmonicity was evidenced. According to X-ray diffraction, the partial filling of the different Al sites leads to occurrence of lowand high-symmetry coordination of Fe atoms, which provides explanation of two doublets evidenced in collected Mo & uml;ssbauer spectra. All spectral parameters of the doublets as well as the Debye temperature, force constant, kinetic and potential energies of vibrations were determined. Those results revealed significant differences between both alloys, likely originating from approaching the stability boundary of the 1-phase for Fe-Al 72.17 at% alloy.

Automated summary

By using Mössbauer spectroscopy and X-ray diffraction, the crystal structure of two FeAl intermetallic compounds and the dynamics of Fe and Al atoms at different temperatures were studied. Significant differences between the two alloys were revealed, likely originating from approaching the stability boundary of the 1-phase for the Fe-Al 72.17 at% alloy.