Influence of Σ5 grain boundaries on crack propagation mechanisms in Ni3Al by molecular dynamics method

XH Qu and C Feng and L Ma, AIP ADVANCES, 15, 095320 (2025).

DOI: 10.1063/5.0279333

The influence of Sigma 5 grain boundaries (GBs) on crack propagation in Ni3Al alloy was investigated under uniaxial loading by molecular dynamics simulation. Two Sigma 5 GBs were constructed in Ni3Al alloy, and a crack was inserted in the middle of Sigma 5 GBs. Then uniaxial loading was carried out along the direction perpendicular to the crack at room temperature. The results showed that the crack model of the Sigma 5 GBs in Ni3Al alloy presented very good plasticity and had a long aging plastic deformation process from the variation trend of the stress-strain curve, and a large number of slip bands were generated at the crack tip and around Sigma 5 GBs. When the crack extended to the Sigma 5 GBs, interactions occurred, which prevented the crack from continuing to expand, and forced the direction of crack propagation to change and propagate along the Sigma 5 GBs. At the same time, by analyzing the variation trend of crack length, it could also be verified that the Sigma 5 GBs had a good blocking effect on crack propagation in Ni3Al alloy. (c) 2025 Author(s). All article content, except where otherwise noted, is licensed under a Creative Commons Attribution- NonCommercial 4.0International (CC BY-NC) license (https://creativecommons.org/licenses/by-nc/4.0/).

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