Effects of single and dual beam Fe and He ion irradiation on NbMoTaW and Ti2ZrHfV0.5Mo0.2 refractory high-entropy alloys

• Published in: Journal of nuclear materials Vol. 615; p. 155936
• Main Authors: Zhang, Peng, Li, Na, Zhang, Xiaonan, Hao, Jinhua, Mei, Xianxiu
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 01.09.2025
• Subjects: Dislocation loops; Dual-beam irradiation; Helium bubbles; Refractory high entropy alloys (RHEAs); Refractory high entropy alloys (RHEAs); Dislocation loops; Dual-beam irradiation; Helium bubbles
• ISSN: 0022-3115
• DOI: 10.1016/j.jnucmat.2025.155936

•Dual-beam (Fe+He) irradiation effects on RHEAs were studied.•Ti RHEA exhibited larger He bubbles due to its higher vacancy concentration and DPA.•Strong lattice distortion in Ti RHEA suppressed dislocation evolution.•He clusters/He bubbles showed a pinning effect on dislocations.•Ti RHEA exhibited only slight irradiation hardening compared to Nb RHEA. This study compared the behavior of two refractory high-entropy alloys (RHEAs), NbMoTaW and Ti₂ZrHfV0.5Mo0.2 (Nb RHEA and Ti RHEA), under single-beam Fe ion, single-beam He ion, and dual-beam irradiation, with a focus on He bubble evolution, dislocation generation, and irradiation hardening. Microscopic characterization revealed that, under both single-beam He ion and dual-beam irradiation, the size of He bubbles in Ti RHEA was larger than in Nb RHEA. Under dual-beam irradiation, the high displacement per atom (DPA) induced by Fe ion implantation promoted the growth of He bubbles, resulting in larger He bubble sizes in both RHEAs compared to those observed under single-beam He ion irradiation. The two RHEAs exhibited distinct dislocation evolution behaviors. Under single-beam ion irradiation, small, dense dislocation loops formed in the low DPA region, while dislocation line networks were observed in the high DPA region of Nb RHEA. Conversely, in Ti RHEA, high-density small dislocation loops were observed only in the damage peak region, while no evident irradiation-induced dislocation loops were observed in the front or attenuation regions. Under dual-beam irradiation, He clusters/He bubbles were observed to pin dislocations in both RHEAs. Nanoindentation results showed that the hardening of Nb RHEA was greater than in Ti RHEA. Nb RHEA exhibited the greatest hardening under single-beam He ion irradiation, while Ti RHEA exhibited the greatest hardening under dual-beam irradiation, which correlated with the distinct dislocation evolution behavior in the two alloys.