An XAFS study on reconstruction of short-range order in mechanically alloyed Al-Ti and Al-Ti-O complexes

Mechanically alloyed (MA) Al-Ti and Al-O-Ti complexes have been studied by X-ray absorption fine structure (XAFS) at the Ti K-edge. In the MA mixture of Al and Ti, the single pre-edge peak due to the electron transition 1s-->3d disappears, and the intensity of the first nearest neighbor peak in the EXAFS structure function \F(r)\ decreases. In the MA mixture of Al and TiO2 hydrogel, the number of pre-edge peaks apparently decreases from three to one. At the same time, the intensity of the \F(r)\ peak due to the first nearest neighbor increases, and its position approaches that of Al2TiO5. Similar phenomena are observed in the MA mixture of Al2O3 and TiO2 hydrogels, These results suggest that mechanical stressing causes characteristic electronic interaction and the reconstruction of short-range order through intimate mixing at an atomic level. This accords with our previous NMR studies.