Grain boundary segregation of C, N and O in hcp titanium from first-principles

TL;DR

This study uses first-principles calculations to investigate the segregation behavior of light interstitials C, N, and O at grain boundaries in titanium, revealing that such segregation is energetically unfavorable and affects grain boundary properties.

Contribution

It provides new insights into the energetics of interstitial segregation at titanium grain boundaries using first-principles methods.

Findings

Segregation of C, N, and O at the grain boundary is energetically unfavorable.

Interstitials increase grain boundary width and formation energy.

Results suggest limited role of these interstitials in thermal stability of titanium alloys.

Abstract

It is believed that grain boundary segregation of light interstitials can serve as possible mechanism of thermal stability in commercially pure nanostructured titanium alloys. In this paper, using first-principles calculations, we show that independent segregation of C, N and O atoms at \Sigma 7 high angle grain boundary in \alpha-Ti is energetically unfavourable. The presence of interstitial elements near and at the grain boundary interface results in the increase of the grain boundary width and specific formation energy.