Hierarchical-interface design for stable helium storage and structural evolution in homogeneous nano-multilayered Al1.5CoCrFeNi high entropy alloy films

• Published in: Surface & coatings technology 2022-06, Vol.439, p.128393, Article 128393
• Main Authors: Pu, Guo, Li, Qiran, Wang, Yihan, Li, Jia, Chen, Sheng, Zhang, Kun, Yang, Chi, Wang, Zhijun, Lin, Liwei, Ren, Ding, Ye, Zongbiao, Liu, Bin, Liu, Bo
• Format: Article
• Language: English
• Subjects: Body centered cubic lattice; Crystal defects; Entrapment; Evolution; Face centered cubic lattice; Grain boundaries; He bubbles; Helium; Helium management; Hierarchical-interface; High entropy alloy films; High entropy alloys; Interfaces; Irradiation; Nanocrystals; Phase transformation; Phase transitions; Radiation; Radiation tolerance
• ISSN: 0257-8972; 1879-3347
• DOI: 10.1016/j.surfcoat.2022.128393

Hierarchical interfaces and nanometer grain boundaries (GBs) were synchronously designed inside the homogeneous Al1.5CoCrFeNi high entropy alloy (HEA) nano-multilayered films, in which each lamellae was composed of nano-crystals to construct helium (He) ion radiation-tolerant materials used for future advanced nuclear-energy system. The depth profile of He behavior and phase-structure evolution in the irradiated [Al1.5CoCrFeNi (10 nm)]30 and [Al1.5CoCrFeNi (30 nm)]10 nano-multilayered films were investigated systematically. Results indicated that the He bubble size in multilayered film exhibited a reduction tendency and a wide distribution feature as the individual-thickness increased from 10 nm to 30 nm, demonstrating inverse results with previous heterogeneous-interface modeling. Reduced bubble pressures were identified in the two kinds of nano-multilayered HEA films, indicating that the coexistence of nanocrystals and homogeneous-interfaces was beneficial to manage He distribution and prolonged bubble growth effectively by tailoring each-lamellae size in these two kinds of multilayered Al1.5CoCrFeNi HEA films. Partial phase transformation from body-centered-cubic (BCC) to face-centered-cubic (FCC) structure was induced through promoting the structural evolution between the irradiation-induced amorphous regions and compositional reorganization in these nano-multilayered HEA films upon irradiation. The interfaces and GBs promoted the annihilation of these defects and further facilitated the self-healing behavior. Such hierarchical-interface in the HEA provides a novel strategy for the effective He entrapment in improving radiation tolerance and a potential possibility of real-application. •Hierarchical-interfaces and nanometer grain boundaries were designed for managing helium distribution in nano-multilayered Al1.5CoCrFeNi HEA films.•The reduced pressure inside helium bubble was effectively tuned by tailoring the each-lamellae size.•The phase structure evolution was explained by irradiation-induced amorphous regions and compositional reorganization.