Atomic-scale investigation of hydrogen distribution in a Ti-Mo alloy

TL;DR

This study uses atom probe tomography to analyze hydrogen distribution in Ti-Mo alloys, revealing phase boundary segregation and the effect of Mo content on hydrogen uptake, which impacts alloy failure mechanisms.

Contribution

It provides the first atomic-scale quantification of hydrogen distribution in Ti-Mo alloys, highlighting phase boundary behavior and Mo's role in hydrogen suppression.

Findings

Hydrogen does not segregate at grain boundaries in fully ta samples.

Hydrogen segregates at lpha/ta phase boundaries with >20 at.% H.

Hydrogen concentration decreases linearly with increasing Mo content.

Abstract

Ingress of hydrogen is often linked to catastrophic failure of Ti-alloys. Here, we quantify the hydrogen distribution in fully \b{eta} and {\alpha}+\b{eta} Ti-Mo alloys by using atom probe tomography. Hydrogen does not segregate at grain boundaries in the fully \b{eta} sample but segregates at some {\alpha}/\b{eta} phase boundaries with a composition exceeding 20 at.% in the {\alpha}+\b{eta} sample. No stable hydrides were observed in either sample. The hydrogen concentration in \b{eta} phases linearly decreases from ~13 at. % to ~4 at. % with increasing Mo-content, which is ascribed to the suppression of hydrogen uptake by Mo addition.