The effect of isochronous annealing on the surface characteristics of Ni$_{50}$Ti$_{50}$ metal glass ribbons

Crystallization of NiTi ribbon metallic glass of equiatomic composition has been studied by x-ray structural analysis and atomic force microscopy. The surface of the original ribbon obtained by spinning contained only crystallites of impurity phases. As a result of exposure to annealing for 10 min at a temperature of 500$^\circ$C, a phase transition has been observed in the form of Ni$_{50}$Ti$_{50}$ phase ordering. The parameters of inhomogeneities, roughness, fractal dimension, and values of multifractal formalism have been calculated in the analysis of the ribbon surface geometry. It has been found that all the above characteristics had local extremes after heat treatment at 500$^\circ$C for 10 min. In particular, the minimum of the values of the widths of the spectra of singularities has been observed, indicating system monofractalization.