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UKAEA-CCFE-PR(20)792020
Point defects in body-centred cubic Fe, Cr and concentrated random magnetic Fe-Cr are investigated using density functional theory and theory of elasticity. The volume of a substitutional Cr atom in ferromagnetic bcc Fe is approximately 18% larger than the volume of a host Fe atom, whereas the volume of a substitutional Fe atom in antiferromagnetic…
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UKAEA-CCFE-PR(20)782020
During an accident with loss-of-coolant and air ingress in DEMO, the temperature of tungsten first wall cladding may exceed 1000oC and remain for months leading to tungsten oxidation. The radioactive tungsten oxide can be mobilized to the environment at rates of 10 – 150 kg per hour. Smart tungsten-based alloys are under develop…
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UKAEA-CCFE-PR(19)382019
Multi-component alloy Fe-Cr-Mn-Ni is a promising new candidate system not only because of its potential application as structural materials beyond conventional austenitic steels but also for fundamental physics role played by Mn element in Fe-Cr-Ni based alloys. In this work, the phase stability of magnetic face-centered cubic (fcc) Fe-Cr-Mn-Ni sys…
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UKAEA-CCFE-PR(18)842018
Configuration entropy is believed to stabilize disordered solid solution phases in multicomponent systems at elevated temperatures over intermetallic compounds by lowering the Gibbs free energy. Traditionally the …
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UKAEA-CCFE-PR(18)772018
A novel W-based refractory high entropy alloy with outstanding radiation resistance has been developed. The alloy was grown as thin films showing a bimodal grain size distribution in the nanocrystalline and ultrafine regimes and a unique 4 nm lamella-like structure revealed by atom probe tomography (APT). Transmission electron microscopy (TEM) and …
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2017
The structural and magnetic properties of CoCrFeyNi and CoCrFeNi-Pdx alloys earlier investigated experimentally by x-ray and neutron diffraction techniques and magnetometry have been theoretically reproduced using two complementary approaches for electronic structure calculations, i.e. the Korringa–Kohn–Rostoker method with the coherent potenti…
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CCFE-PR(17)552017
High Entropy Alloys (HEAs) is a fascinating field of research, with an increasing number of new alloys discovered. This would hardly be conceivable without the aid of materials modeling and the computational alloy design to investigate the immense compositional space. The simplicity of the microstructure achieved contrasts with the enormous complex…
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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. …
Showing 21 - 30 of 37 UKAEA Paper Results