FORMATION OF ATOMIC ORDERING DURING HEATING AND ANNEALING OF NiAl3 ALLOY

10.25712/ASTU.1811-1416.2025.04.003

Abstract

Intermetallic compounds of the Ni-Al system, formed in the aluminum-rich region of the phase diagram, namely NiAl₃ and Ni₂Al₃, remain poorly understood. The limitations of experimental and theoretical studies of these compounds include their complex crystallographic structure and relatively low melting points. In this paper, molecular dynamics simulation was used to study the formation of the atomic structure during heating and annealing of the NiAl₃ intermetallic compound with the D0₁₁ superstructure. The computational cell consisted of 16000 atoms. Interatomic interactions were defined using the embedded atom potential approximation developed by Mishin et al. An analysis of the atomic distribution in the crystal was performed using the Cowley short-range order parameter and X-ray diffraction. The Cowley parameter values are estimated for several coordination spheres at different temperatures, allowing one to observe changes in atomic ordering with increasing temperature. X-ray diffraction line profiles were constructed during heating and annealing. Satisfactory agreement between the interplanar spacings calculated for virtual diffraction patterns and experimental values is demonstrated.