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arXiv · 2411.13665

Atomistic insights into Cu segregation effects on irradiation-induced defect dynamics in medium-entropy alloys

Kazi Tawseef Rahman·Mustofa Sakif Shahriar·Mashaekh Tausif Ehsan·Mohammad Nasim Hasan
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Abstract

Copper (Cu) segregation in medium and high-entropy alloys (M/HEAs) has shown significant influence on alloy properties. In this study, we investigate the effect of Cu segregation on evolution of irradiation-induced defects in FeNiCu, a model MEA, using hybrid molecular dynamics (MD) and Monte Carlo (MC) simulations. Thermodynamically driven hybrid MC/MD annealing at low temperature resulted in a partially decomposed Cu-segregated structure (CSS) and was compared with a random solid solution (RSS) and pure Ni. Results through cumulative displacement cascades reveal that Cu-rich domains in CSS act as defect traps, accelerating interstitial-vacancy recombination and suppressing defect cluster growth. The complex potential energy landscape (PEL) in CSS disrupts dislocation propagation, leading to spatially dispersed networks. Notably, CSS exhibits reduced stair-rod dislocation density compared to RSS, highlighting its superior resistance to irradiation swelling. Localized shear strain causes dislocations to preferentially nucleate in/near Cu-rich regions though their growth is hindered by chemical heterogeneity of the alloy. Notably, prolonged irradiation induces slow Cu segregation in the RSS structure, while slowly annihilating pre-existing Cu clusters in CSS simultaneously. The findings provide atomic-scale insights into the interplay between Cu segregation and irradiation-induced defect evolution in MEAs.

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Kazi Tawseef Rahman, Mustofa Sakif Shahriar, Mashaekh Tausif Ehsan, Mohammad Nasim Hasan. 2024-11-20. Atomistic insights into Cu segregation effects on irradiation-induced defect dynamics in medium-entropy alloys. https://doi.org/10.1088/1361-651x%2Fae2f78

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