TEM and XPS Study of Ball-Milled Fe1 – xAlx Alloys

Abstract

The ball milling technique has been extensively used to prepare different metastable states with nanocrystalline microstructures from intermetallic compounds. In the present manuscript, the authors have systematically investigated the structural and electronic properties of a series of mechanically alloyed Fe1 -xAlx (0.3 ≤ x ≤ 0.6) samples using transmission electron microscopy (TEM) and X-ray photoelectron spectroscopy (XPS). The ball milling process causes the formation of solid-state reactions that are aided by severe plastic deformation, resulting in reduced crystallite size and interesting microstructural and electronic changes in the resulting system. The TEM results show that the crystallite size decreases to the nanometer range (between 6-8 nm) as a function of x and the metals dissolve at the nanograin boundaries. As a result of nanometric dimensions, the reactivity increases as a result of the increased surface-to-volume ratio, which leads to the FeAl alloy phase formation. The XPS survey scan shows that the samples do not have any major contamination, and the core level spectra show a slight shift of Fe2p and Al2p peaks toward higher binding energy (BE), which proves that different Fe-and Al-rich phases of FeAl alloy have formed after 5 h of milling.