Crystallization of Ni₅₀Ti₅₀ metallic glass ribbon in the concept of multifractal formalism

ABSTRACT

The NiTi metallic glass ribbon was subjected to 10-minute annealing at 400°C, 500°C and 600°C to detect changes in the surface relief and its statistical characteristics upon heating. Each annealing mode led to the ribbon crystallization with the formation of the Ni₅₀Ti₅₀ crystalline phases along with the transformation of the surface topography. Multifractal characteristics, such as the width of the singularity spectrum and fractal dimension, were calculated for the surface relief as a function of an annealing temperature. After the annealing at 500°C, along with the stepwise surface structure rearrangements, these parameters had extrema, including a local minimum of the width of the singularity spectrum, indicating a tendency towards monofractalization of the system. Abrupt changes in the parameters calculated by applying the multifractal formalism made it possible to detect the phase transition of the system in the form of its crystallization.

KEYWORDS:

• NiTi metallic glass
• surface relief
• phase transition
• crystallization
• multifractal formalism
• singularity spectrum

Disclosure statement

No potential conflict of interest was reported by the author(s).