Effects of aluminum on hydrogen solubility and diffusion in deformed Fe-Mn alloys

TL;DR

This study investigates how aluminum alloying affects hydrogen solubility and diffusion in deformed Fe-Mn alloys using ab initio calculations, trap site theory, and diffusion modeling, revealing local and volumetric influences of Al.

Contribution

It provides a detailed analysis of aluminum's impact on hydrogen behavior in Fe-Mn alloys through combined computational methods, highlighting both chemical and volumetric effects.

Findings

Aluminum influences hydrogen solubility and diffusion via local chemical effects.

Deformation modes affect hydrogen diffusion pathways.

Aluminum's effects include both local and nonlocal contributions.

Abstract

We discuss hydrogen diffusion and solubility in aluminum alloyed Fe-Mn alloys. The systems of interest are subjected to tetragonal and isotropic deformations. Based on ab initio modelling, we calculate solution energies, then employ Oriani's theory which reflects the influence of Al alloying via trap site diffusion. This local equilibrium model is complemented by qualitative considerations of Einstein diffusion. Therefore, we apply the climbing image nudged elastic band method to compute the minimum energy paths and energy barriers for hydrogen diffusion. Both for diffusivity and solubility of hydrogen, we find that the influence of the substitutional Al atom has both local chemical and nonlocal volumetric contributions.