TRANSFORMATION FROM ICOSAHEDRAL QUASI-CRYSTALLINE TO AMORPHOUS STRUCTURE IN AL65CU20FE15

Mechanical grinding (MG) of icosahedral AL65Cu20Fe15 quasicrystal has been performed by ball milling for up to 200 hours. Specimens, taken after different milling times, were examined by X-ray diffraction and transmission Fe-57 Mossbauer spectroscopy. It is found that MG led to structural changes from quasicrystalline to amorphous phase. Two possible transformation mechanisms with the corresponding fitting models for evaluation of the Mossbauer spectra are proposed. The model consisting of two blocks of the P(DELTA) distributions of the electric quadrupole interaction is superior to that one which assumes only one P(A) suggesting a creation of an amorphous phase and its gradual increase in the specimen's volume during the ball milling of icosahedral quasicrystal.