Size effect on the structure of Al-and Ni-based nanocrystals

The structure of nanocrystals formed upon crystallization of amorphous alloys of the Ni-Mo-B and Al-Ni-RE systems (RE = Y, Yb, Ce) was studied using x-ray diffraction and high-resolution transmission electron microscopy. It is shown that the lattice parameters and the existence of structural defects depend on the alloy composition and heat treatment conditions. At the beginning of crystallization, all nanocrystals are defectless. After the first stage of crystallization is completed, the aluminum nanocrystals remain perfect, whereas the nanocrystals of molybdenum solid solution contain numerous defects. It is revealed that the nanocrystals of the same size in different systems are either defectless (Al₈₂Ni₁₁Ce₃Si₄, Al₈₈Ni₁₀Y₂, etc.) or contain numerous defects (Ni₇₀Mo₃₀)₉₀B₁₀.