Abnormal grain growth mediated by fractal boundary migration at the nanoscale

Abstract Modern engineered materials are composed of space-filling grains or domains separated by a network of interfaces or boundaries. Such polycrystalline microstructures have the capacity to coarsen through boundary migration. Grain growth theories account for the topology of grains and the conn...

Descripción completa

Guardado en:
Detalles Bibliográficos
Autores principales: Christian Braun, Jules M. Dake, Carl E. Krill, Rainer Birringer
Formato: article
Lenguaje:EN
Publicado: Nature Portfolio 2018
Materias:
R
Q
Acceso en línea:https://doaj.org/article/28e5f55897c546a29ee41325689eb774
Etiquetas: Agregar Etiqueta
Sin Etiquetas, Sea el primero en etiquetar este registro!
Descripción
Sumario:Abstract Modern engineered materials are composed of space-filling grains or domains separated by a network of interfaces or boundaries. Such polycrystalline microstructures have the capacity to coarsen through boundary migration. Grain growth theories account for the topology of grains and the connectivity of the boundary network in terms of the familiar Euclidian dimension and Euler’s polyhedral formula, both of which are based on integer numbers. However, we recently discovered an unusual growth mode in a nanocrystalline Pd-Au alloy, in which grains develop complex, highly convoluted surface morphologies that are best described by a fractional dimension of ∼1.2 (extracted from the perimeters of grain cross sections). This fractal value is characteristic of a variety of domain growth scenarios—including explosive percolation, watersheds of random landscapes, and the migration of domain walls in a random field of pinning centers—which suggests that fractal grain boundary migration could be a manifestation of the same universal behavior.