Tailoring negative pressure by crystal defects: Microcrack induced hydride formation in Al alloys

A Tehranchi and P Chakraborty and ML Freixes and EJ Mceniry and B Gault and T Hickel and J Neugebauer, PHYSICAL REVIEW MATERIALS, 7, 105401 (2023).

DOI: 10.1103/PhysRevMaterials.7.105401

Climate change motivates the search for non-carbon-emitting energy generation and storage solutions. Metal hydrides show promising characteristics for this purpose. They can be further stabilized by tailoring the negative pressure of microstructural and structural defects. Using systematic ab initio and atomistic simulations, we demonstrate that an enhancement in the formation of hydrides at the negatively pressurized tip region of the microcrack is feasible by increasing the mechanical tensile load on the specimen. The theoretical predictions have been used to reassess and interpret atom probe tomography experiments for a high-strength 7XXX-aluminium alloy that show a substantial enhancement of hydrogen concentration at structural defects near a stress-corrosion crack tip. These results contain important implications for enhancing the capability of metals as H-storage materials.

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