The Spectrum of Interstitial Solute Energies in Polycrystals

TL;DR

This paper introduces a computational approach to measure and analyze the spectrum of interstitial solute energies at grain boundaries in polycrystals, specifically applied to the Pd-H system, revealing distinct site energy distributions and a thermodynamic model that aligns with experimental data.

Contribution

It presents a novel computational method to characterize the spectrum of segregation energies at grain boundaries and develops a thermodynamic model for equilibrium segregation in polycrystals.

Findings

Spectrum of segregation energies consists of two normal-like distributions.

Thermodynamic isotherm accurately predicts equilibrium segregation states.

Model aligns well with experimental data for Pd-H system.

Abstract

A computational method is presented to measure the spectrum of segregation energies for an interstitial solute at grain boundaries (GBs) in a polycrystal. For the Pd-H system, that spectrum of GB interstitial segregation energies is found to consist of a mixture of two normal-like distributions, characteristic of GB octahedral and tetrahedral sites. We also derive a thermodynamic isotherm to calculate the equilibrium segregation state in a polycrystal that recognizes the need for referencing two interstitial site types, and show that it conforms well to experimental data in the Pd-H system.