Formation of ordered and disordered interfacial films in immiscible metal alloys

TL;DR

This study uses atomistic simulations to explore how segregation influences the formation of ordered and disordered interfacial films in Cu-Zr and Cu-Nb alloys, revealing differences in film structure, stability, and effects of boundaries and surfaces.

Contribution

It provides new insights into the atomistic mechanisms governing interfacial film formation and stability in immiscible metal alloys, highlighting the role of boundary type and dopant concentration.

Findings

Cu-Zr forms amorphous intergranular films

Cu-Nb develops ordered second-phase films

Boundary energy influences film disordering transition

Abstract

Atomistic simulations are used to study segregation-induced intergranular film formation in Cu-Zr and Cu-Nb alloys. While Cu-Zr forms structurally disordered or amorphous films, ordered films comprised of a second phase usually precipitate in Cu-Nb, with a critical nucleation size of ~1 nm below which the ordered phase cannot form. While the ordered film is retained at high temperature for a low energy {\Sigma}11 (113) boundary, a disordering transition is observed for a high energy {\Sigma}5 (310) boundary at low dopant concentrations. Finally, the effect of free surfaces on dopant segregation and intergranular film formation is investigated for both alloys.