Formation of the nanostructure in amorphous alloys of the Al-Ni-Y system

The formation of the amorphous-nanocrystalline structure during the crystallization of metallic glasses of the Al-Ni-Y system has been investigated by X-ray diffractometry, differential scanning calorimetry, and transmission electron microscopy. It has been shown that the crystallization onset temperature depends on the chemical composition of the alloy, and the crystallization is accompanied by changes in the structure of the amorphous phase, such as the phase separation and the formation of amorphous regions of various compositions with different short-range orders. The nanocrystals nucleate in the amorphous phase by the heterogeneous mechanism. It has been found that the size of precipitated aluminum nanocrystals depends on the alloy composition. The amorphous-nanocrystalline structure formed during the thermal treatment is stable and remains unchanged during the isothermal annealing at 150°C for 500 h.