Order-disorder transitions in the Fe2VAl Heusler alloy. (December 2016)

• Record Type: Journal Article
• Authors: Maier, S.; Denis, S.; Adam, S.; Crivello, J.-C.; Joubert, J.-M.; Alleno, E.
• Is Part Of: Acta materialia. Volume 121(2016)
• Page Start: 126
• Page End: 136
• Publication Date: 2016-12
• Subjects: Heusler alloys -- Order-disorder transition -- Antisite defects -- Cold work -- Thermoelectricity; Materials -- Periodicals; Materials science -- Periodicals; Materials -- Mechanical properties -- Periodicals; Metallurgy -- Periodicals; Chemistry, Inorganic -- Periodicals; 620.112
• DOI: 10.1016/j.actamat.2016.08.080
• Languages: English
• ISSNs: 1359-6454

Abstract

Abstract: A Rietveld analysis of neutron powder diffraction patterns obtained in situ during temperature scans shows that Fe2 VAl crystallizes at room temperature in the fully ordered L 21 structure and transforms at 1080 °C and at 1190 °C into partially disordered B 2 and fully disordered A 2 variants respectively. The low temperature stability of the L 21 structure as well as the two high temperature L 21 → B 2 → A 2 transitions are theoretically predicted by a combination of ab-initio (electronic structure and phonons) and thermodynamic calculations performed on special quasi-random structures. Pronounced cold work effects and the pre-transitional antisite defects which are observed respectively at 25 °C under mechanical stress and at high temperature (above 800 °C), appear to be generic effects in the family of Heusler alloys. Graphical abstract: