An electro-chemo-mechanical framework for predicting hydrogen uptake in metals due to aqueous electrolytes

TL;DR

This paper introduces a comprehensive electro-chemo-mechanical model to predict hydrogen absorption in metals exposed to aqueous electrolytes, accounting for electrochemical reactions, diffusion, and mechanical deformation.

Contribution

It develops a novel theoretical and numerical framework that explicitly couples electrochemical, chemical, and mechanical processes for hydrogen ingress prediction in metals.

Findings

Maps relating hydrogen uptake to potential, geometry, and fluid velocity

Validated simplified models against the general framework

Established regimes of validity for different models

Abstract

We present a theoretical and numerical scheme that enables quantifying hydrogen ingress in metals for arbitrary environments and defect geometries. This is achieved by explicitly resolving the electrochemical behaviour of the electrolyte, the hydrogen and corrosion reactions, the kinetics of surface adsorption, and hydrogen uptake, diffusion and trapping in mechanically-deforming solids. This new framework is used to produce maps that relate the absorbed hydrogen with the applied potential, specimen geometry and fluid velocity. We also present simplified versions of our generalised model, and benchmark predictions of these and other existing models against the generalised electro-chemo-mechanical results, establishing regimes of validity.