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CCFE-PR(17)142017
In high-entropy alloys (HEAs), the local chemical fluctuations from disordered solute solution state into segregation, precipitation and ordering configurations are complex due to the large number of elements. In this work, the cluster expansion (CE) Hamiltonian for multi-component alloy systems is developed in order to investigate the dependence o…
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CCFE-PR(16)522016
Helium is produced in the structural materials of nuclear power plants by the nuclear transmutation following neutron irradiation. Since the solubility of helium in all the metals is extremely low, helium tends to be trapped at defects such as vacancies, dislocations and grain boundaries, which cause materials embrittlement. Density functional the…
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CCFE-PR(16)512016
The properties of point defects in Fe-Cr-Ni alloys are investigated, using density functional theory (DFT), for two alloy compositions, Fe50Cr25Ni25 and Fe55Cr15Ni30, assuming various degrees of short-range order. DFT-based Monte Carlo simulations are applied to explore short-range order parameters and generate representative structures of alloys. …
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CCFE-PR(16)492016
Multicomponent systems, termed High Entropy Alloys (HEAs), with predominantly single solid solution phases are a current area of focus in alloy development. Although different empirical rules have been introduced to understand phase formation and determine what the dominant phases may be in these systems, experimental investigation has revealed tha…
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CCFE-PR(15)612015
A methodology to compute the distribution of interatomic distances in highly concentrated multicomponent alloys is proposed. By using the unit cell parameter and bulk modulus of the elements involved, the method accurately describes the distortion in the lattice produced by the interaction of the different atomic species. To prove this, density fun…
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CCFE-PR(15)932015
The occurrence of segregation in highly dilute alloys under irradiation is an unusual phenomenon that has so far eluded theoretical explanation. The fact that solute atoms segregate in alloys that, according to thermodynamics, exhibit full solubility, has significant practical implications, as the formation of precipitates strongly affects physical…
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CCFE-PR(15)1202015
Low-energy magnetic states and finite-temperature properties of Cr nanoclusters in bulk bcc Fe and Fe nanoclusters in bulk Cr are investigated using density functional theory (DFT) and the Heisenberg-Landau Hamiltonian based magnetic cluster expansion (MCE). We show, by means of noncollinear magnetic DFT calculations, that magnetic frustration caus…
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CCFE-PR(15)1072015
The phase stability of fcc and bcc magnetic binary Fe-Cr, Fe-Ni, and Cr-Ni alloys, and ternary Fe-Cr-Ni alloys is investigated using a combination of density functional theory (DFT), cluster expansion (CE), and magnetic cluster expansion (MCE) approaches. Energies, magnetic moments, and volumes of more than 500 alloy structures have been evaluated …
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CCFE-PR(15)632015
A Magnetic Cluster Expansion model for ternary face-centered cubic Fe-Ni-Cr alloys has been developed, using DFT data spanning binary and ternary alloy configurations. Using this Magnetic Cluster Expansion model Hamiltonian, we perform Monte Carlo simulations and explore magnetic structures of alloys over the entire range of compositions, consideri…
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2014
A model lattice ab initio parameterized Heisenberg–Landau magnetic cluster expansion Hamiltonian spanning a broad range of alloy compositions and a large variety of chemical and magnetic configurations has been developed for face-centered cubic Fe–Ni alloys. The thermodynamic and magnetic properties of the alloys are explored using configuratio…
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