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

The evolution of the microstructure of (Fe1-xVx)(3)Al alloys in the D0(3) s tructure has been studied as function of composition by transmission electr on 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 a lso shown. This microstructural evolution is discussed in terms of the incr eased second nearest neighbor interactions induced by the V additions. Elec tronic 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 f eature is discussed in terms of interesting physical properties of the syst em and in relation to the density of states, stability and properties of si milar 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 a ffect the unoccupied Al s and d states. (C) 2000 Elsevier Science Ltd. All rights reserved.