Effects of alloying and grain boundary on primary irradiation defects in FeNiCrCoCu high entropy alloys: A molecular dynamics study

B Almomani and MJ Banisalman and O Elgack and J Syarif, MATERIALS TODAY COMMUNICATIONS, 45, 112237 (2025).

DOI: 10.1016/j.mtcomm.2025.112237

High-entropy alloys (HEAs) have been identified as promising structural materials due to their superior mechanical properties, thermal stability, and resistance to irradiation. This research aims to investigate the primary damage formation in single crystal and polycrystalline structures for FeNiCrCoCu HEA exposed to fast particle irradiation using molecular dynamics (MD) simulations. Collision cascades were produced by the recoil of 100 key primary knock-on atoms (PKA) in four distinct HEA compositions, namely 28Ni, 12Co, 16Co, and 20Ni. These alloys were distinguished by increased nickel and decreased cobalt content, standing out due to their high ultimate tensile strength. PKAs were initiated under cryogenic conditions a long one of <100>, <110>, <111>, or <321> crystallographic directions in the center of a MD simulation box to induce quantifiable radiation damage. The analysis investigated radiation-induced defects using the Wigner-Seitz cell method to quantify the number of residual defects such as Frenkel pairs (FPs) and interstitial clusters. Moreover, the CNA and DXA techniques were utilized to identify interstitial dislocation loops (IDLs), stacking faults, and to assess the role of grain boundaries (GBs) in mitigating radiation damage. The results indicated diverse radiation resistance across alloy compositions with consistent associations between interstitial clusters and survived FPs, IDLs, and peak FPs in all structures. An imbalance in the number of vacancies and interstitial atoms was observed after the relaxation of collision cascades in polycrystalline HEA, primarily attributed to the preferential absorption of interstitial atoms by GBs. This highlights the interaction between compositional alloying complexity and GBs enhances the recombination and annihilation mechanisms. The findings emphasize the HEAs' potential in highradiation environments, guiding future research for advanced alloys with improved performance.

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