High-Entropy Grain Boundaries

TL;DR

This paper explores the thermodynamics and stabilization mechanisms of high-entropy grain boundaries in alloys and ceramics, highlighting their potential to enhance high-temperature stability and structural properties.

Contribution

It provides the first comprehensive thermodynamic analysis of high-entropy grain boundaries, introducing a simplified segregation model applicable to both alloys and ceramics.

Findings

High-entropy grain boundaries reduce energy with increasing temperature.

HEGBs can stabilize nanocrystalline alloys at high temperatures.

Structural disordering in GBs offers opportunities for higher entropy states.

Abstract

Do high-entropy alloys and ceramics have their grain boundary (GB) counterparts? As the concept of high-entropy grain boundaries (HEGBs) was initially proposed in 2016, this article provides the first complete and rigorous discussion of the underlying interfacial thermodynamics. A simplified segregation model can illustrate both GB and bulk high-entropy effects, which reduce GB energy with increasing temperature for saturated multicomponent (conventional and high-entropy) alloys. HEGBs can be utilized to stabilize nanocrystalline alloys at high temperatures via thermodynamic and kinetic effects. GB structural disordering and transitions offer further opportunities to attain higher effective GB entropies. Future perspective is discussed.