Ab initiocalculation of anisotropic interfacial excess free energies

Abstract

We describe a simple method to determine, from ab initio calculations, the complete orientationdependence of interfacial free energies in solid-state crystalline systems. We illustrate the method with an application to precipitates in the Al-Ti alloy system. The method combines the cluster expansion formalism in its most general form (to model the system's energetics) with the inversion of the well-known Wulff construction (to recover interfacial energies from equilibrium precipitate shapes). Although the inverse Wulff construction only provides the relative magnitude of the various interfacial free energies, absolute free energies can be recovered from a calculation of a single, conveniently chosen, planar interface. The method is able to account for essentially all sources of entropy (arising from phonons, bulk point defects, as well as interface roughness) and is thus able to transparently handle both atomically smooth and rough interfaces. The approach expresses the resulting orientation-dependence of the interfacial properties using symmetry-adapted bases for general orientation-dependent quantities. As a by-product, this paper thus provides a simple and general method to generate such basis functions, which prove useful in a variety of other applications, for instance to represent the anisotropy of the so-called constituent strain elastic energy.

Orientation relationships and interfaces of the Fe–Zn intermetallic phases in galvannealed CMnSi-TRIP steels

“…The cube-on-cube OR between cubic/cubic or cubic/tetragonal crystals having a lattice mismatch of 15% or less is predicted theoretically [22][23][24] and has indeed been frequently observed [25][26][27]. This is also confirmed by this research on the Γ 2 /Γ 1 and α-Fe/Γ 1 ORs.…”

Solid–liquid interfacial free energy of ice Ih, ice Ic, and ice 0 within a mono-atomic model of water via the capillary wave method

“…In the general case, generation of appropriate functions in a suitable form is non-trivial. Implementation of an automated method for doing so, with only the crystallographic unit cell as input, 34 is available via the "gencs" utility distributed with the Alloy Theoretic Automated Toolkit (ATAT). 35 This enables application of the capillary wave method to a much wider range of systems.…”

A high-performance anode material based on FeMnO3/graphene composite

“…We populate these metal sites with Fe and Mn equally and randomly and construct the computational unit cell using the special quasi-random structure (SQS) method. An SQS was generated based on a Monte Carlo algorithm implemented in ATAT [37][38][39][40][41][42][43][44][45][46][47] with the constraint that the pair and triplet correlation functions of the SQS are identical to those of the statistically random Fe/Mn population of cation sites at least up to the third nearest neighbor.…”