Title: Point defect evolution in Ni, NiFe and NiCr alloys from atomistic simulations and irradiation experiments

Abstract

Using molecular dynamics simulations, we elucidate irradiation-induced point defect evolution in fcc pure Ni, Ni_0.5Fe_0.5, and Ni_0.8Cr_0.2 solid solution alloys. We find that irradiation-induced interstitials form dislocation loops that are of 1/3 <111>{111}-type, consistent with our experimental results. While the loops are formed in all the three materials, the kinetics of formation is considerably slower in NiFe and NiCr than in pure Ni, indicating that defect migration barriers and extended defect formation energies could be higher in the alloys than pure Ni. As a result, while larger size clusters are formed in pure Ni, smaller and more clusters are observed in the alloys. The vacancy diffusion occurs at relatively higher temperatures than interstitials, and their clustering leads to formation of stacking fault tetrahedra, also consistent with our experiments. The results also show that the surviving Frenkel pairs are composition-dependent and are largely Ni dominated.

Authors:

Aidhy, Dilpuneet S. ^[1]; Lu, Chenyang ^[2]; Jin, Ke ^[1]; Bei, Hongbin ^[1]; Zhang, Yanwen ^[1]; Wang, Lumin ^[2]; Weber, William J. ^[3]

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+ Show Author Affiliations

1. Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Materials and Technology Div.
2. Univ. of Michigan, Ann Arbor, MI (United States). Dept. of Nuclear Engineering and Radiological Sciences
3. Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Materials and Technology Div.; Univ. of Tennessee, Knoxville, TN (United States). Materials Science and Engineering

Publication Date:

Sat Aug 08 00:00:00 EDT 2015

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:

1209216

Alternate Identifier(s):

OSTI ID: 1251431

Grant/Contract Number:  

AC05-00OR22725; AC02-05CH11231

Resource Type:

Accepted Manuscript

Journal Name:

Acta Materialia

Additional Journal Information:

Journal Volume: 99; 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 1359-6454

Publisher:

Elsevier

Country of Publication:

United States

Language:

English

Subject:

36 MATERIALS SCIENCE