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Title: Impact of alloy composition on one-dimensional glide of small dislocation loops in concentrated solid solution alloys

Abstract

One-dimensional glide of loops during ion irradiation at 773 K in a series of Ni-containing concentrated solid solution alloys has been observed directly during experiments conducted inside a transmission electron microscope. It was found that the frequency of the oscillatory motion of the loop, the loop glide velocity as well as the loop jump distance were dependent on the composition of the alloy and the size of the loop. Loop glide was most common for small loops and occurred more frequently in the less complex alloys, being highest in Ni, then NiCo, NiFe and NiCoFeCr. As a result, no measurable loop glide occurred in the NiCoCr, NiCoFeCrMn and NiCoFeCrPd alloys.

Authors:
 [1];  [2];  [1]
  1. Univ. of Wisconsin, Madison, WI (United States)
  2. Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
Publication Date:
Research Org.:
Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
Sponsoring Org.:
USDOE Office of Science (SC)
OSTI Identifier:
1366401
Grant/Contract Number:
AC05-00OR22725
Resource Type:
Journal Article: Accepted Manuscript
Journal Name:
Materials Science and Engineering. A, Structural Materials: Properties, Microstructure and Processing
Additional Journal Information:
Journal Volume: 700; Journal Issue: C; Journal ID: ISSN 0921-5093
Publisher:
Elsevier
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; loop glide; concentrated solid solution alloys; ion irradiation; transmission electron microscopy

Citation Formats

Shi, Shi, Bei, Hongbin, and Robertson, Ian M. Impact of alloy composition on one-dimensional glide of small dislocation loops in concentrated solid solution alloys. United States: N. p., 2017. Web. doi:10.1016/j.msea.2017.05.049.
Shi, Shi, Bei, Hongbin, & Robertson, Ian M. Impact of alloy composition on one-dimensional glide of small dislocation loops in concentrated solid solution alloys. United States. doi:10.1016/j.msea.2017.05.049.
Shi, Shi, Bei, Hongbin, and Robertson, Ian M. 2017. "Impact of alloy composition on one-dimensional glide of small dislocation loops in concentrated solid solution alloys". United States. doi:10.1016/j.msea.2017.05.049.
@article{osti_1366401,
title = {Impact of alloy composition on one-dimensional glide of small dislocation loops in concentrated solid solution alloys},
author = {Shi, Shi and Bei, Hongbin and Robertson, Ian M.},
abstractNote = {One-dimensional glide of loops during ion irradiation at 773 K in a series of Ni-containing concentrated solid solution alloys has been observed directly during experiments conducted inside a transmission electron microscope. It was found that the frequency of the oscillatory motion of the loop, the loop glide velocity as well as the loop jump distance were dependent on the composition of the alloy and the size of the loop. Loop glide was most common for small loops and occurred more frequently in the less complex alloys, being highest in Ni, then NiCo, NiFe and NiCoFeCr. As a result, no measurable loop glide occurred in the NiCoCr, NiCoFeCrMn and NiCoFeCrPd alloys.},
doi = {10.1016/j.msea.2017.05.049},
journal = {Materials Science and Engineering. A, Structural Materials: Properties, Microstructure and Processing},
number = C,
volume = 700,
place = {United States},
year = 2017,
month = 6
}

Journal Article:
Free Publicly Available Full Text
This content will become publicly available on June 8, 2018
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  • We investigate Irradiation-induced damage accumulation in Ni 0.8Fe 0.2 and Ni 0.8Cr 0.2 alloys by using molecular dynamics simulations to assess possible enhanced radiation-resistance in these face-centered cubic (fcc), single-phase, concentrated solid-solution alloys, as compared with pure fcc Ni.
  • A long-standing objective in materials research is to understand how energy is dissipated in both the electronic and atomic subsystems in irradiated materials, and how related non-equilibrium processes may affect defect dynamics and microstructure evolution. Here we show that alloy complexity in concentrated solid solution alloys having both an increasing number of principal elements and altered concentrations of specific elements can lead to substantial reduction in the electron mean free path and thermal conductivity, which has a significant impact on energy dissipation and consequentially on defect evolution during ion irradiation. Enhanced radiation resistance with increasing complexity from pure nickel tomore » binary and to more complex quaternary solid solutions is observed under ion irradiation up to an average damage level of 1 displacement per atom. Understanding how materials properties can be tailored by alloy complexity and their influence on defect dynamics may pave the way for new principles for the design of radiation tolerant structural alloys.« less
  • It has been shown that concentrated solid solution alloys possess unusual electronic, magnetic, transport, mechanical and radiation-resistant properties that are directly related to underlying chemical complexity. Because every atom experiences a different local atomic environment, the formation and migration energies of vacancies and interstitials in these alloys exhibit a distribution, rather than a single value as in a pure metal or dilute alloy. In this study, using ab initio calculations based on density functional theory and special quasirandom structure, we have characterized the distribution of defect formation energy and migration barrier in four Ni-based solid-solution alloys: Ni 0.5Co 0.5, Nimore » 0.5Fe 0.5, Ni 0.8Fe 0.2 and Ni 0.8Cr 0.2. As defect formation energies in finite-size models depend sensitively on the elemental chemical potential, we have developed a computationally efficient method for determining it which takes into account the global composition and the local short-range order. In addition we have compared the results of our ab initio calculations to those obtained from available embedded atom method (EAM) potentials. Our results indicate that the defect formation and migration energies are closely related to the specific atomic size in the structure, which further determines the elemental diffusion properties. In conclusion, different EAM potentials yield different features of defect energetics in concentrated alloys, pointing to the need for additional potential development efforts in order to allow spatial and temporal scale-up of defect and simulations, beyond those accessible to ab initio methods.« less