Amorphous complexions enable a new region of high temperature stability in nanocrystalline Ni-W

TL;DR

This paper demonstrates that amorphous intergranular films in nanocrystalline Ni-W alloys enable high-temperature stability, surpassing traditional solute segregation methods, and introduce a new stabilization mechanism at elevated temperatures.

Contribution

It reveals that amorphous complexions can stabilize nanocrystalline structures at high temperatures, offering an alternative to solute segregation for grain growth control.

Findings

Amorphous intergranular films form in Ni-W after high-temperature annealing and rapid quenching.

These films create a new stability region for nanocrystalline Ni-W at elevated temperatures.

The study suggests amorphous complexions as a novel stabilization mechanism for nanocrystalline metals.

Abstract

Solute segregation is used to limit grain growth in nanocrystalline metals, but this stabilization often breaks down at high temperatures. Amorphous intergranular films can form in certain alloys at sufficiently high temperatures, providing a possible alternative route to lower grain boundary energy and therefore limit grain growth. In this study, nanocrystalline Ni-W that is annealed at temperatures of 1000 {\deg}C and above, then rapidly quenched, is found to contain amorphous intergranular films. These complexions lead to a new, unexpected region of nanocrystalline stability at elevated temperatures.