Atomic Structural Features of Grain Boundary Complexions in Alumina

Abstract

Grain boundaries in polycrystalline microstructures are often decorated with dopants that are added intentionally, or impurities that are acquired during processing and service. The nature of the foreign substances profoundly influences various materials properties including diffusional transport, interfacial fracture, oxidation, corrosion and creep resistance. In many metallic and ceramic systems interfaces with various types of segregation, from sub-monolayer to thick microscopic films, have been observed. Recently, these interface phases have been considered as thermodynamically distinct three dimensional phases, called Grain Boundary Complexions.1-2 In the current work, alumina has been chosen as a model system to study the various boundary complexion types and its relationship with boundary mobility.