Modeling the amorphous structure of a mechanically alloyed Ti50Ni25Cu25 alloy using anomalous wide-angle x-ray scattering and reverse Monte Carlo simulations

TL;DR

This study combines anomalous wide-angle x-ray scattering and reverse Monte Carlo simulations to elucidate the atomic structure of a mechanically alloyed amorphous Ti50Ni25Cu25 alloy, revealing detailed local atomic arrangements.

Contribution

It introduces a novel approach integrating anomalous scattering data with RMC simulations to characterize the atomic structure of amorphous alloys.

Findings

Different chemical environments around Ni and Cu atoms were identified.

Partial structure factors and pair distribution functions were successfully computed.

Coordination numbers and interatomic distances for first neighbors were determined.

Abstract

An amorphous Ti50Ni25Cu25 alloy was produced by 19 h of mechanical alloying. Anomalous wide angle x-ray scattering data were collected at six energies and six total scattering factors were obtained. By considering the data collected at two energies close to the Ni and Cu K edges, two differential anomalous scattering factors around the Ni and Cu atoms were obtained, showing the chemical environments around these atoms are different. The eight factors were used as input data to the reverse Monte Carlo method used to compute the partial structure factors STi-Ti(K), STi-Cu(K), STi-Ni(K), SCu-Cu(K), SCu-Ni(K) and SNi-Ni(K). From their Fourier transformation, the partial pair distribution functions GTi-Ti(r), GTi-Cu(r), GTi-Ni(r), GCu-Cu(r), GCu-Ni(r) and GNi-Ni(r) were obtained, and the coordination numbers and interatomic atomic distances for the first neighbors were determined.