Modelling and Monte Carlo simulation of the atomic ordering processes in Ni₃Al intermetallics

Abstract

The evolution of atomic ordering processes in Ni3Al has been modelled by a Monte Carlo (MC) simulation method combined with the electronic theory of alloys in pseudopotential approximation. The magnitudes of atomic ordering energies of atomic pairs in the Ni3Al system have been calculated by means of electronic theory in pseudopotential approximation up to the 4th coordination spheres and subsequently used as input data for MC simulation for more detailed analysis for the first time. The Bragg–Williams long-range order (LRO) and Cowley–Warren short-range order (SRO) parameters have been calculated from the equilibrium configurations attained at the end of the MC simulation for each predefined temperature and Al concentration levels which reveal the evolution of the system from the L12 → disordered state as the temperature increases. The values of the LRO and SRO parameters at temperatures below 800 °C justify the existence of L12-type ordered Ni3Al alloys for all concentration levels whereas at temperatures above 850 °C, the values of the LRO parameter implies the presence of a disordered solid solution of Ni3Al alloys. However, a higher degree of the SRO order parameter above the predicted order–disorder transition temperature is preserved up to the melting point of Ni3Al intermetallics. The composition dependence of the LRO and SRO parameters agrees well with the experimental results.

Effect of vanadium on atomic ordering characteristics and anti-phase boundary energies of B2–FeCo alloys

“…Stochastic nature of evolutions of atomic arrangements and processes can well be realized by MC methods, which are previously employed several times to study atomic ordering processes in various intermetallics by authors' group [21,22]. In the present work, a similar approach is utilized to quantify the evolution of atomic ordering and APBs with temperature in FeCo and FeCo-V systems.…”

“…(2) and (3) in which the contribution of the d-resonance effect is relatively small [37]. Therefore, the Animalu's model pseudopotential has been successfully applied previously for evaluation of various characteristics of the Ni-and Fe-based binary and multi-component transition metal systems [21,22,[29][30][31][32][33]. Thus, partial ordering energies of atomic pairs in FeCo-V alloys are calculated up to first five CSs based on Eqs.…”

Site Selection and Pseudo-Clustering Behaviors of Alloying Elements in Aluminum-Lean γ-TiAl Intermetallics

“…[27][28][29][30][31][32][33][34][35] The partial ordering energy of an A-B pair in ternary alloys can be defined as where F AB ðqÞ ¼ À…”

A phase-field study on the formation of the intermetallic Al2Au phase in the Al–Au system

“…Monte Carlo [12] and front-tracking [13,14] methods have been used for the study of intermetallic alloys. A review concerning first principle as well as molecular dynamic investigations on intermetallic compounds can be found in Ref.…”