The structural evolution and stability of Fe100-xNix（x= 10, 20, 35, 50） alloys prepared by mechanical alloying were investigated through X-ray diffraction analysis and transmission electron microscopy. The intrinsic...The structural evolution and stability of Fe100-xNix（x= 10, 20, 35, 50） alloys prepared by mechanical alloying were investigated through X-ray diffraction analysis and transmission electron microscopy. The intrinsic conditions of preparation determining phase stability in nanocrystalline were clarified. After being milled for 120 h, the powders of Fego Ni10 and Fe80 Ni20 consist of a single α（bcc） phase, Fe30 Ni30 powders are a single γ（fcc）, and for Fe65 Ni35 powders there is co-existence of α and γ phases. The as-milled Fe80 Ni20 powders annealed at 680℃ exhibits the stability of high-temperature γ phase at room temperature, which is consistent with the theoretical prediction.展开更多
Despite great efforts to study magnetic properties of 3d-transition metals from both fundamental and applied interest,there exists no modelling approach that would be able to describe magnetic and structural phase sta...Despite great efforts to study magnetic properties of 3d-transition metals from both fundamental and applied interest,there exists no modelling approach that would be able to describe magnetic and structural phase stability of all these elements on a unified formalism.In this work,we propose a qualitative improvement of the Generalisation of the Universal Equation of States(GUES)that we presented recently in a previous work developed and tested for cubic structures in Fe.The GUES is now extended to other 3d-transition magnetic elements and crystal lattices,where now magnetic Co,Cr,Mn,and Ni are considered,including both cubic and hexagonal structures,and also covering ferromagnetic(FM)and antiferromagnetic(AFM)configurations.An extensive database has been developed and used to fit all parameters and functions for all considered elements.The current GUES unifies the two previous separate approaches for FM and AFM configurations,allowing for noncollinear calculations,which are tested for Co,Cr,Fe,Mn and Ni.The approach is consistent with the Stoner model of band magnetism and the Ginzburg-Landau approximation used in the magnetic cluster expansion method,as well as with non-collinear magnetism described in the Heisenberg-Landau Hamiltonians.Importantly,it also includes magneto-volume effects,which are important for understanding defect properties in magnetic materials.This work permits considering the development of a new class of magnetic interatomic potentials for non-collinear simulations based on the approach proposed by the GUES.(The figures shown in this article can be seen in colour only in the electronic version).展开更多
文摘The structural evolution and stability of Fe100-xNix（x= 10, 20, 35, 50） alloys prepared by mechanical alloying were investigated through X-ray diffraction analysis and transmission electron microscopy. The intrinsic conditions of preparation determining phase stability in nanocrystalline were clarified. After being milled for 120 h, the powders of Fego Ni10 and Fe80 Ni20 consist of a single α（bcc） phase, Fe30 Ni30 powders are a single γ（fcc）, and for Fe65 Ni35 powders there is co-existence of α and γ phases. The as-milled Fe80 Ni20 powders annealed at 680℃ exhibits the stability of high-temperature γ phase at room temperature, which is consistent with the theoretical prediction.
基金support of the project INNUMAT(Ref:101061241),from the Euratom Program HORIZON-EURATOM-2021-NRT-01The simulations were carried out with the support of the Interdisciplinary Centre for Mathematical and Computational Modeling(ICM),University of Warsaw,under grant No.GB79-6+2 种基金ITC would like to thank to the DIGImeTAL project(Ref:TED2021-132214B-I00),from the Proyectos Estratégicos Orientados a la Transición Ecológica y a la Transición Digital 2021,funded by the Plan de Recuperación,Transformación y Resiliencia,Spanish Ministerio de Ciencia,Innovación y UniversidadesThis work has also been carried out within the framework of the EUROfusion Consortium,from which JSW and DNM have received funding from the Euratom research and training program 2014-2018 and 2019-2020 under grant agreement No 633053The views and opinions expressed herein do not necessarily reflect those of the European Commission.DNM’s work is supported by the UK-EPSRC Energy Program[grant number EP/W006839/1].Finally,JSW and DNM acknowledge the support from high-performing computing facility MARCONI(Bologna,Italy)provided by EUROfusion.The authors are also grateful to the Digital Laboratory of Metallurgy from CENIM-CSIC and the access to the high-performing server facilities.
文摘Despite great efforts to study magnetic properties of 3d-transition metals from both fundamental and applied interest,there exists no modelling approach that would be able to describe magnetic and structural phase stability of all these elements on a unified formalism.In this work,we propose a qualitative improvement of the Generalisation of the Universal Equation of States(GUES)that we presented recently in a previous work developed and tested for cubic structures in Fe.The GUES is now extended to other 3d-transition magnetic elements and crystal lattices,where now magnetic Co,Cr,Mn,and Ni are considered,including both cubic and hexagonal structures,and also covering ferromagnetic(FM)and antiferromagnetic(AFM)configurations.An extensive database has been developed and used to fit all parameters and functions for all considered elements.The current GUES unifies the two previous separate approaches for FM and AFM configurations,allowing for noncollinear calculations,which are tested for Co,Cr,Fe,Mn and Ni.The approach is consistent with the Stoner model of band magnetism and the Ginzburg-Landau approximation used in the magnetic cluster expansion method,as well as with non-collinear magnetism described in the Heisenberg-Landau Hamiltonians.Importantly,it also includes magneto-volume effects,which are important for understanding defect properties in magnetic materials.This work permits considering the development of a new class of magnetic interatomic potentials for non-collinear simulations based on the approach proposed by the GUES.(The figures shown in this article can be seen in colour only in the electronic version).
