Relationship between grain boundary segregation and grain boundary diffusion in Cu-Ag alloys

Abstract

While it is known that alloy components can segregate to grain boundaries (GBs), and that the atomic mobility in GBs greatly exceeds the atomic mobility in the lattice, little is known about the effect of GB segregation on GB diffusion. Atomistic computer simulations offer a means of gaining insights into the segregation-diffusion relationship by computing the GB diffusion coefficients of the alloy components as a function of their segregated amounts. In such simulations, thermodynamically equilibrium GB segregation is prepared by a semi-grand canonical Monte Carlo method, followed by calculation of the diffusion coefficients of all alloy components by molecular dynamics. As a demonstration, the proposed methodology is applied to a GB is the Cu-Ag system. The GB diffusivities obtained exhibit non-trivial composition dependencies that can be explained by site blocking, site competition, and the onset of GB disordering due to the premelting effect.

References in corpus (5)

• Structural phase transformations in metallic grain boundaries
• Effect of interface phase transformations on diffusion and segregation in high-angle grain boundaries
• Molecular dynamics modeling of self-diffusion along a triple junction
• Irreversible thermodynamics of creep in crystalline solids
• An atomistic view of grain boundary diffusion

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• Atomistic modeling of bulk and grain boundary diffusion in solid electrolyte Li${}_6$PS${}_5$Cl using machine-learning interatomic potentials