High spatial resolution peels characterization of FeAl nanograins preparedby mechanical alloying

We investigate the nanograin "chemicai" structure in a nanostructured mater ial of possible industrial application (Fe-Al system) prepared by conventio nal mechanical alloying via ball milling in argon atmosphere. We restrict o urselves to the structural and nanochemical behaviour of ball-milled nanocr ystalline Fe-Al powders with atomic composition Fe3Al, corresponding to a w ell-known intermetallic compound of the Fe-Al system. Scanning transmission electron microscopy (STEM) equipped with a parallel detection electron ene rgy loss spectrometer (PEELS) has provided an insight on the "chemical" str ucture of both nanograins and their surface at a spatial resolution of bett er than 1 nm. The energy loss near edge structure of the Al L loss reveals that the Al coordination is similar to a B2 compound and the oxidation of t he powder during processing may play a significant role in the stabilizatio n of the intermetallic phases. Conventional transmission electron microscop y (TEM) was used for the structural characterization of the material after the ball milling; powder X-ray diffraction (XRD) aided the investigation. ( C) 1999 Acta Metallurgica Inc. Published by Elsevier Science Ltd. All right s reserved.