Binary L12 Intermetallics: A Statistical‐Thermodynamic Modeling of Ordering Phenomena, Behavior and Properties

Abstract

AbstractThe main objective of this paper is aimed towards a correct statistical‐thermodynamic modeling and description of the effects and changes associated with the creation of different defects in the crystal structure and their connection and influence on the properties of the binary L12 intermetallic systems. This was done by the using of a General Defect Correlation Model (GDCM), employing applications of the Bragg‐Williams‐Gorsky mean‐field approximation. The obtained results are compared to a model based on the Wagner‐Schottky approach with application of the grand canonical ensemble for non‐interacting point defects for description of the arrangement of anti‐structure and vacancy defects. The basic concept includes the evaluation of such characteristics of the intermetallic materials with L12 structures as the virtual critical temperatures of order‐disorder transformations, the pair‐wise interaction and defect formation energies, thermodynamic activities and defect concentrations, and also descriptions of long‐ranged (LRO) and short‐ranged (SRO) atomic correlations in the crystal lattice (including the possible correlation of nearest neighbor point defect combinations), which is difficult to obtain by other methods. The model calculations also are tested using experimental data on thermodynamic and structural properties.