Isolation, observation and quantification of mechanisms responsible for hydrogen embrittlement by TRITIum based microMEchanics

Introduction

Hydrogen is an indispensable element in the energy transition and is expected to be key for the decarbonization of European society. Hydrogen embrittlement – recognized and in focus of materials science for almost 150 years – still causes catastrophic failures today.

Understanding Hydrogen Embrittlement

It is well understood that all mechanisms of hydrogen embrittlement materialize at the scale of individual defects, such as:

• Dislocations
• Grain boundaries
• Phase boundaries

However, we are still missing a correlative measurement of the mechanical behavior of individual defects and the local hydrogen content. This measurement is urgently needed to assess the occurrence, importance, and magnitude of mechanisms playing a role during hydrogen embrittlement.

TRITIME Project Overview

In aid of this, TRITIME facilitates the isolation, observation, and quantification of hydrogen embrittlement mechanisms by tritium-based micromechanics. The mechanisms of hydrogen embrittlement will be isolated through small-scale mechanical testing on samples containing only a few crystal defects.

Experimental Techniques

The defect properties will be observed and measured by:

1. In situ micromechanical experiments in the scanning electron microscope
2. Experiments at synchrotron beamlines

Simultaneously, TRITIME will monitor the local hydrogen content by observing the decay of tritium with high spatial resolution, for which a unique tool will be developed.

Post Mortem Analysis

In addition, post mortem analysis using:

• Atom probe tomography
• Secondary ion mass spectroscopy

will take advantage of the reduced mobility of tritium. TRITIME will provide unprecedented insights into the local hydrogen content of newly formed slip bands, mobile and immobile dislocations, and fracture surfaces.

Conclusion

Consequently, if successful, TRITIME will obtain a mechanism-based, quantitative understanding of HEDE, HELP, and their interplay. In doing so, TRITIME sets the base for a mechanism-based optimization of microstructures used in the distribution and storage of hydrogen and, therefore, is an indispensable tool towards Europe’s hydrogen society.