Features of primary damage by high energy displacement cascades in concentrated Ni-based alloys

Journal Article · 24 February 2016 · Journal of Applied Physics

DOI: https://doi.org/10.1063/1.4942533 · OSTI ID:1239766

Béland, Laurent Karim  ^[1]; Lu, Chenyang ^[2]; Osetskiy, Yuri N. ^[1]; Samolyuk, German D. ^[1]; Caro, Alfredo ^[3]; Wang, Lumin ^[2]; Stoller, Roger E. ^[1]

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1. Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
2. Univ. of Michigan, Ann Arbor, MI (United States)
3. Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

Alloying of Ni with Fe or Co reduces primary damage production under ion irradiation. Similar results have been obtained from classical molecular dynamics simulations of 1, 10, 20, and 40 keV collision cascades in Ni, NiFe, and NiCo. In all cases, a mix of imperfect stacking fault tetrahedra, faulted loops with a 1/3 {111} Burgers vector, and glissile interstitial loops with a 1/2 {110} Burgers vector were formed, along with small sessile point defect complexes and clusters. Primary damage reduction occurs by three mechanisms. First, Ni-Co, Ni-Fe, Co-Co, and Fe-Fe short-distance repulsive interactions are stiffer than Ni-Ni interactions, which lead to a decrease in damage formation during the transition from the supersonic ballistic regime to the sonic regime. This largely controls final defect production. Second, alloying decreases thermal conductivity, leading to a longer thermal spike lifetime. The associated annealing reduces final damage production. These two mechanisms are especially important at cascades energies less than 40 keV. Third, at the higher energies, the production of large defect clusters by subcascades is inhibited in the alloys. A number of challenges and limitations pertaining to predictive atomistic modeling of alloys under high-energy particle irradiation are discussed.

• Research Organization: Energy Frontier Research Centers (EFRC) (United States). Energy Dissipation to Defect Evolution (EDDE); Oak Ridge National Laboratory (ORNL), Oak Ridge, TN (United States)
• Sponsoring Organization: USDOE Office of Science (SC), Basic Energy Sciences (BES); USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22)
• Grant/Contract Number: AC05-00OR22725
• OSTI ID: 1239766
• Journal Information: Journal of Applied Physics, Journal Name: Journal of Applied Physics Journal Issue: 8 Vol. 119; ISSN JAPIAU; ISSN 0021-8979
• Publisher: American Institute of Physics (AIP)Copyright Statement
• Country of Publication: United States
• Language: English