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.