Microstructural evolution and stability of (Fe1-xVx)3Al alloys in relation to the electronic structure.

The evolution of the microstructure of (Fe1-xVx)(3)Al alloys in the D0(3) structure has been studied as function of composition by transmission electron microscopy. The domain size of the D03 structure significantly increases as V is added to the alloy. An increase in long range order parameter is also shown. This microstructural evolution is discussed in terms of the increased second nearest neighbor interactions induced by the V additions. Electronic structure calculations are also presented in this paper. The density of states shows a strong pseudogap for the Fe2VAl compound and thus strong hybridization induced by the alloying element. This electronic structure feature is discussed in terms of interesting physical properties of the system and in relation to the density of states, stability and properties of similar compounds [Fe2MAl (M = Ti, Cr, Mn)]. Electron energy loss spectra of the Al L2-3 edge show that the strong hybridization induced by V does not affect the unoccupied Al s and d states. (C) 2000 Elsevier Science Ltd. All rights reserved.