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

Abstract

Alloying of Ni with Fe or Co has been shown to reduce 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.

Authors:

Béland, Laurent Karim  ^[1];

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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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+ Show Author Affiliations

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)

Publication Date:

Thu Feb 25 00:00:00 EST 2016

Research Org.:

Oak Ridge National Laboratory (ORNL), Oak Ridge, TN (United States); Energy Frontier Research Centers (EFRC) (United States). Energy Dissipation to Defect Evolution (EDDE)

Sponsoring Org.:

USDOE Office of Science (SC), Basic Energy Sciences (BES)

OSTI Identifier:

1239766

Alternate Identifier(s):

OSTI ID: 1421163

Grant/Contract Number:  

AC05-00OR22725; EDDE EFRC

Resource Type:

Accepted Manuscript

Journal Name:

Journal of Applied Physics

Additional Journal Information:

Journal Volume: 119; Journal Issue: 8; Related Information: EDDE partners with Oak Ridge National Laboratory (lead); Lawrence Livermore National Laboratory; University of Michigan; University of Tennessee; University of Wisconsin; University of Wyoming; Virginia Tech; Journal ID: ISSN 0021-8979

Publisher:

American Institute of Physics (AIP)

Country of Publication:

United States

Language:

English

Subject:

74 ATOMIC AND MOLECULAR PHYSICS