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Local segregation versus irradiation effects in high-entropy alloys: Steady-state conditions in a driven system

Koch, Leonie and Granberg, Fredric and Brink, Tobias and Utt, Daniel and Albe, Karsten and Djurabekova, Flyura and Nordlund, Kai (2017):
Local segregation versus irradiation effects in high-entropy alloys: Steady-state conditions in a driven system.
In: Journal of Applied Physics, pp. 105106 (1-10), 122, (10), ISSN 0021-8979,
[Online-Edition: https://doi.org/10.1063/1.4990950],
[Article]

Abstract

We study order transitions and defect formation in a model high-entropy alloy (CuNiCoFe) under ion irradiation by means of molecular dynamics simulations. Using a hybrid Monte-Carlo/molecular dynamics scheme, a model alloy is generated which is thermodynamically stabilized by configurational entropy at elevated temperatures, but partly decomposes at lower temperatures by copper precipitation. Both the high-entropy and the multiphase sample are then subjected to simulated particle irradiation. The damage accumulation is analyzed and compared to an elemental Ni reference system. The results reveal that the high-entropy alloy—independent of the initial configuration—installs a certain fraction of short-range order even under particle irradiation. Moreover, the results provide evidence that defect accumulation is reduced in the high-entropy alloy. This is because the reduced mobility of point defects leads to a steady state of defect creation and annihilation. The lattice defects generated by irradiation are shown to act as sinks for Cu segregation.

Item Type: Article
Erschienen: 2017
Creators: Koch, Leonie and Granberg, Fredric and Brink, Tobias and Utt, Daniel and Albe, Karsten and Djurabekova, Flyura and Nordlund, Kai
Title: Local segregation versus irradiation effects in high-entropy alloys: Steady-state conditions in a driven system
Language: English
Abstract:

We study order transitions and defect formation in a model high-entropy alloy (CuNiCoFe) under ion irradiation by means of molecular dynamics simulations. Using a hybrid Monte-Carlo/molecular dynamics scheme, a model alloy is generated which is thermodynamically stabilized by configurational entropy at elevated temperatures, but partly decomposes at lower temperatures by copper precipitation. Both the high-entropy and the multiphase sample are then subjected to simulated particle irradiation. The damage accumulation is analyzed and compared to an elemental Ni reference system. The results reveal that the high-entropy alloy—independent of the initial configuration—installs a certain fraction of short-range order even under particle irradiation. Moreover, the results provide evidence that defect accumulation is reduced in the high-entropy alloy. This is because the reduced mobility of point defects leads to a steady state of defect creation and annihilation. The lattice defects generated by irradiation are shown to act as sinks for Cu segregation.

Journal or Publication Title: Journal of Applied Physics
Volume: 122
Number: 10
Uncontrolled Keywords: Amorphous metals, Transition, Crystal defects, Molecular dynamics, Entropy
Divisions: 11 Department of Materials and Earth Sciences > Material Science > Materials Modelling
Zentrale Einrichtungen > University IT-Service and Computing Centre (HRZ) > Hochleistungsrechner
11 Department of Materials and Earth Sciences > Material Science
Zentrale Einrichtungen > University IT-Service and Computing Centre (HRZ)
11 Department of Materials and Earth Sciences
Zentrale Einrichtungen
Date Deposited: 19 Sep 2017 11:39
Official URL: https://doi.org/10.1063/1.4990950
Identification Number: doi:10.1063/1.4990950
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