Effect of molybdenum substitution on crystal structure of ordered Fe–Al alloys

Abstract

Abstract The substitution behaviour of molybdenum in B2 and D03 Fe–Al alloys having aluminium contents between 22 and 37 at.-% has been investigated using differential thermal analysis and X-ray diffraction. It is shown that low (5%) substitution of molybdenum for iron resulted in a significant (up to 175°C) increase in both B2 and D03 ordering temperatures, but larger (10 and 15%) additions of molybdenum did not continue this trend to the same magnitude due to the formation of molybdenum rich precipitates. It was shown using X-ray diffraction that molybdenum substitutes for iron on the B sites of the D03 structure and on the B/C sites for the B2 structure. The increase of B2 and D03 ordering temperatures is interpreted in terms of changes in bonding behaviour in bcc, B2, and D03 structures resulting from molybdenum substitution.MST/1716