Irradiation performance of concentrated solid-solution alloys: Insight into defect behaviors

• Published in: Journal of nuclear materials 2023-09, Vol.583, p.154510, Article 154510
• Main Authors: Zhao, Yan, Li, Yaojun, Yang, Fan, Xie, Zhen, Wu, Xiaoyong, Wang, Yuexia
• Format: Article
• Language: English
• Subjects: Displaced defect; Irradiation cascade; Molecular dynamics; SP-CSAs
• ISSN: 0022-3115; 1873-4820
• DOI: 10.1016/j.jnucmat.2023.154510

•A legibly physical picture of irradiation effects is given in CSAs, which is remarkably distinguished from conventional metals.•Threshold displacement energy decreases with increasing constituent elements in CSAs.•Lower thermal conductivity and localization of defects prolong thermal annealing time and promote recombination of defects. Lattice distortion retards defects accumulation in cascades. All of these characteristics contribute to irradiation-resistance of CSAs. Single-phase concentrated solid-solution alloys (SP-CSAs) intensively attracted researchers for their promising performances and tailorable constituents. In this work, molecular dynamic simulations were employed to investigate the radiation effects in equiatomic FeCrNi and FeNi, compared with an elemental Ni, mainly based on threshold displacement energy (Ed), individual recoil and overlapping cascades. Anisotropy of Ed distribution is a common feature in the three materials. However, defect behaviors concerning production in a single cascade and accumulation in multi-cascade process all exhibit distinctive features, which are particularly distinguished between CSAs and the elemental Ni. The discrepancy starts from the defect creation in the colliding phase, escalates in the thermal annealing phase of the single cascade, and is further amplified in the overlapping cascades. Corresponding physical processes involve atomic collision, heat dissipation and atomic diffusion. We discussed the channeling effect of atomic collision, thermal conductivity and sluggish diffusion in the CSAs to discover the origin causing the difference in defect morphology. Concentrated distribution of defects created in the colliding phase and low thermal dissipation contributes to higher defect recombination rate in the CSAs. Sluggish effect suppressing defect mobility further balances the production and annihilation of defects during the multi-cascades. We interpreted why the number of displacement defects is prone to be saturated under multi-cascades and only small-size clusters are left in the CSAs, unlike the pure Ni in which an oversized cluster was observed. The results are beneficial to designing radiation-tolerant materials by shedding light on the genesis of defect morphology in CSAs under irradiations.