STRUCTURAL INVESTIGATION OF A MECHANICALLY ALLOYED AL-FE SYSTEM

Crystalline elemental powders of Al(x)Fe100-x (x = 40-90) were mechanically alloyed by high energy ball-milling. Transmission electron microscopy, Mossbauer spectroscopy and X-ray diffraction techniques were employed in the structural study of Al-Fe alloys prepared by mechanical alloying. The amorphous or nanocrystalline structures were observed in an Al-Fe system within the composition range studied. The structure of the alloy containing (50-80)at.%Al is basically amorphous, while the alloys out of this range are of nanocrystalline phase. A further investigation by high resolution TEM examination shows that very few nanometer order crystallites still existed in the amorphous matrix of the Al80Fe20 alloy. It suggested that 100% amorphization of Al-Fe system cannot be achieved in practice by mechanical alloying.