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

Y Zhao and YJ Li and F Yang and Z Xie and XY Wu and YX Wang, JOURNAL OF NUCLEAR MATERIALS, 583, 154510 (2023).

DOI: 10.1016/j.jnucmat.2023.154510

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 multicascades. We interpreted why the number of displacement defects is prone to be saturated under multicascades 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.

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