Hydrogen and deuterium charging of site-specific specimen for atom probe tomography

TL;DR

This paper presents three workflows for hydrogen/deuterium charging of site-specific atom probe tomography specimens, enabling detailed microstructural analysis of hydrogen interactions in metals to better understand hydrogen embrittlement.

Contribution

It introduces and compares three methods for hydrogen/deuterium charging of APT specimens, addressing challenges and enabling microstructural hydrogen analysis.

Findings

Successful cathodic and gas charging demonstrated

Gas charging is more effective for high-strength steels

Provides detailed discussion on charging method caveats

Abstract

Hydrogen embrittlement can cause a dramatic deterioration of the mechanical properties of high-strength metallic materials. Despite decades of experimental and modelling studies, the exact underlying mechanisms behind hydrogen embrittlement remain elusive. To unlock understanding of the mechanism and thereby help mitigate the influence of hydrogen and the associated embrittlement, it is essential to examine the interactions of hydrogen with structural defects such as grain boundaries, dislocations and stacking faults. Atom probe tomography (APT) can, in principle, analyse hydrogen located specifically at such microstructural features but faces strong challenges when it comes to charging specimens with hydrogen or deuterium. Here, we describe three different workflows enabling hydrogen/deuterium charging of site-specific APT specimens: namely cathodic, plasma and gas charging. We discuss in detail the caveats of the different approaches in order to help with future research efforts and facilitate further studies of hydrogen in metals. Our study demonstrates successful cathodic and gas charging, with the latter being more promising for the analysis of the high-strength steels at the core of our work.