Faceting diagram for Ag segregation induced nanofaceting at an asymmetric Cu tilt grain boundary

TL;DR

This study experimentally characterizes how Ag segregation induces nanofaceting at an asymmetric Cu grain boundary, revealing the relationship between Ag concentration and facet morphology, and providing a nanofaceting diagram.

Contribution

It introduces an experimental nanofaceting diagram for Cu-Ag grain boundaries, linking atomic structure, inclination, and Ag excess, which is a novel insight into grain boundary behavior.

Findings

Ag segregation causes asymmetric nanofaceting at the grain boundary.

Increasing Ag excess lengthens Ag-rich facets while asymmetric facets stay constant.

A nanofaceting diagram correlates Ag concentration with boundary morphology.

Abstract

In this work, we experimentally establish the isothermal nanofacet evolution at an asymmetric tilt grain boundary in the Cu-Ag system using a diffusion couple approach. We investigate the nanofacet formation along the grain boundary in dependence of the Ag solute excess concentration. The initial grain boundary dissociates into asymmetric Ag-lean segments and Ag-rich symmetric (210) segments. Increasing Ag excess leads to an increase in Ag-rich facet segment length, while the length of the asymmetric facets remains constant. From this, we construct a grain boundary nanofaceting diagram deduced from our experiments relating local atomic structure, overall inclination and Ag solute excess.