Modelling Hydrogen Embrittlement using Density Functional Theory: A theoretical approach to understanding environmentally assisted cracking in 7xxx series aluminium alloys

The effects of H segregation to a Σ11 symmetric tilt Al grain boundary are investigated using atomistic simulations, as part of a wider study on cracking in 7xxx series alloys. Density functional theory based simulations of uniaxial straining of grain boundaries containing 11 different concentration...

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Bibliographic Details
Published in:MATEC web of conferences 2020, Vol.326, p.4006
Main Authors: Wilson, Benjamin T., Robson, Joseph D., Race, Christopher P.
Format: Article
Language:English
Subjects:
Alloying elements
Aluminum base alloys
Density functional theory
Environmentally assisted cracking
Fracture mechanics
Grain boundaries
Heat treating
Hydrogen embrittlement
Magnesium
Modelling
Precipitates
Zinc
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Summary:The effects of H segregation to a Σ11 symmetric tilt Al grain boundary are investigated using atomistic simulations, as part of a wider study on cracking in 7xxx series alloys. Density functional theory based simulations of uniaxial straining of grain boundaries containing 11 different concentrations of H were performed under the cohesive zone fracture mechanics framework. The theoretical strength of grain boundaries is shown to be supressed by H segregation, and the cause of this is attributed to the prevention of the formation of Al ligaments across grain boundaries. Segregated concentrations of relevant alloying elements (Zn, Mg, and Cu) show minimal impact on the H embrittlement process investigated, namely H enhanced decohesion (HEDE). Further modelling, of H transport and grain boundary precipitates, is required to confirm the validity of the HEDE mechanism in the case of 7xxx alloys.
ISSN:2261-236X
2274-7214
2261-236X
DOI:10.1051/matecconf/202032604006