Irradiation-induced grain boundary strengthening/embrittlement in bcc refractory high entropy alloy TiZrHfNbTa

CL Xu and PD Li and XB Tian and WT Jiang and QY Wang and HD Fan, JOURNAL OF NUCLEAR MATERIALS, 617, 156163 (2025).

DOI: 10.1016/j.jnucmat.2025.156163

High entropy alloys (HEA) exhibit good mechanical performances and have potential applications in nuclear reactors. In this work, molecular dynamic (MD) simulation was performed to investigate the irradiation- induced grain boundary (GB) strengthening/embrittlement in refractory high entropy alloy (RHEA) TiZrHfNbTa and pure Ta. The distinct responses of low-angle symmetric tilt GB under tensile deformation were simulated. It was found that the irradiation-induced point defects have different influences on the GB fracture. Both the interstitials and vacancies can lead to GB embrittlement in pure Ta. For RHEA, only vacancies can lead to GB embrittlement while the interstitials can strengthen the GB conversely. By measuring the strengthening/embrittlement energy of interstitial and vacancy at GB, the different effects of point defects on GB fracture in pure Ta and RHEA were explained. This work confirmed that the TiZrHfNbTa RHEA shows better irradiation resistance than pure Ta in the perspective of GB behaviors, and provides new insights into understanding the GB regulation mechanism on mechanical properties, which are important for improving the irradiation effects in RHEA.

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