Computing grain boundary “phase” diagrams

Grain boundaries (GBs) can be treated as two-dimensional (2-D) interfacial phases (also called “complexions”) that undergo phase-like transitions. As bulk phase diagrams and calculation of diagram (CALPHAD) methods serve a foundation for modern materials science, we propose to extend them GBs have equally significant impacts. This perspective article reviews series studies compute the GB counterparts diagrams. First, phenomenological thermodynamic model was developed construct lambda forecast high-temperature disordering related trends in sintering other properties both metallic ceramic materials. In parallel, an Ising-type lattice statistical utilized adsorption (segregation) diagrams, which predicted first-order transitions critical phenomena. These two simplified models emphasize structural (disordering) chemical (adsorption) aspects, respectively. Subsequently, hybrid Monte Carlo molecular dynamics atomistic simulations were used more rigorous accurate “phase” Computed further extended include mechanical properties. Moreover, machine learning algorithms combined with predict functions four independent compositional variables temperature 5-D space given high-entropy alloys or five macroscopic (crystallographic) degrees freedom plus composition binary alloy 7-D space. Other relevant are also examined. Future outlook, including emerging fields grain (HEGBs) electrically (or electrochemically) induced transitions, discussed.