Effect of tensile strain on the early oxidation of the nickel-based high-temperature alloy γ'-Ni3Al: Insights from ReaxFF molecular dynamics

DF Qu and ZX Zhu and M Zheng and WH Chen and H Tan and CL Lei, ENGINEERING FAILURE ANALYSIS, 177, 109706 (2025).

DOI: 10.1016/j.engfailanal.2025.109706

The introduction of mechanical forces will accelerate alloy failure by altering the oxidation rate of the alloy. In this paper, the mechanical behavior and chemical reactions of gamma'-Ni3Al alloys under coupled oxidation and stretching are simulated using Reactive Force Field Molecular Dynamics (ReaxFF-MD). Results demonstrate that early oxidation decreased the strength and ductility of the alloy with minimal effect on the elastic properties. The applied stress increases the oxidation rate, charge transfer, coordination number, and the number of atoms involved in the reaction of the alloy, with oxygen concentration exhibiting a positive correlation with these enhancements. Oxygen atoms preferentially accumulate in NiAl-rich regions, driving the formation of highvalent Al ions. Necking phenomena predominantly initiate in high- stress zones characterized by dynamic Al - O bond rupture/reformation. Subsequent re-oxidation leads to localized severe oxidation at necking sites. The exothermic phenomenon of stretching and oxidation promotes the participation of Ni in the oxidation.

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