Aluminium based amorphous and nanocrystalline structure

Abstract

Aluminium based rapidly quenched alloys of nominal composition Al₉₀Fe₇Nb₃ and Al₉₄Fe₂V₄ were studied by Mössbauer spectroscopy. Samples annealed up to 573 K showed amorphous structure represented by quadrupole doublet. From corrected spectra areas the values of f-factor were calculated. In the case of AlFeNb samples f-factor was estimated as f = 0.26 and for AlFeV f = 0.31. The corresponding Debye temperatures were also calculated. Higher temperature annealing at 773 and 873 K induced deformation of nano- and microcrystalline state. Mössbauer spectra of samples of both compositions (with vanadium as well as with niobium) annealed at 773 K showed superposition of crystalline phases with dominant role of Al₃Fe alloy. During annealing at 873 K, phases with large grains and small amount of FeAl metastable phase were developed (Das et al. Mat. Sci. Eng., A304–A306, 159, 2001; Illeková et al. Mat. Sci. Eng., A375–A377, 946, 2004).