Magnetism and origin of non-monotonous concentration dependence of the bulk modulus in Fe-rich alloys with Si, Ge and Sn: a first-principles study

Khmelevska, T.; Khmelevskyi, Sergii; Ruban, Andrei V.; Mohn, P.

doi:10.1088/0953-8984/18/29/009

Cited by 28 publications

(28 citation statements)

References 30 publications

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“…This was attributed to the increasing number of p-p and p-d bonds with the addition of Ge and Sn in Fe. [100] Taking L1 2 -Ni 3 Sn as a prototypical case, in Section B, we show that the bonding mechanism is dominated by p-d hybridization.…”

Section: A Phase Stability Of Ni-sn Intermetallicsmentioning

confidence: 94%

“…[79] Our observations of an increase in the equilibrium atomic volume and a concomitant decrease in the bulk modulus are consistent with the earlier first-principles results of bcc Fe 1-x Ge x and Fe 1-x Sn x alloys, using coherent potential approximation. [100] Both Ge and Sn increase the atomic volume of the bcc solid solution of Fe; they also decrease the bulk modulus. This was attributed to the increasing number of p-p and p-d bonds with the addition of Ge and Sn in Fe.…”

Section: A Phase Stability Of Ni-sn Intermetallicsmentioning

confidence: 99%

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First-Principles Calculation of Phase Stability and Cohesive Properties of Ni-Sn Intermetallics

Ghosh

2008

Metall Mater Trans A

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The cohesive properties of Ni-Sn intermetallics (stable, metastable, and virtual), hitherto unexplored by density-functional theory (DFT) methods, are reported. Specifically, the total energies and cohesive properties of Ni, Sn, and 27 Ni-Sn intermetallics are calculated from firstprinciples, using ultrasoft pseudopotentials (USPP) and both local-density approximation (LDA) and generalized-gradient approximation (GGA) for the exchange-correlation functional. Among the intermetallics considered, the ground-state structures are consistent with experimental observations; however, not all of them are registered in the equilibrium-phase diagram. An important result of this systematic study, using both USPP-LDA and USPP-GGA, is that oC20-NiSn 4 is predicted to be the ground-state structure. Only recently, this phase has been observed as a product of the interfacial reaction in Ni/Sn diffusion couples. In addition, we find that the thermodynamic stability of a tetragonal phase, tP10-NiSn4, is very similar to that of oC20-NiSn 4 . The elastic stability of both tP10-NiSn 4 and oC20-NiSn 4 is confirmed by calculating their single-crystal elastic constants. The calorimetric data for the enthalpy of formation of stable intermetallics show an agreement that is better for those calculated with USPP-LDA than those calculated with USPP-GGA. In general, the experimental lattice parameters of stable and metastable phases are found to lie between those calculated using USPP-LDA and those calculated using USPP-GGA; however, in several cases, the values calculated using USPP-GGA agree to within 1 pct of the experimental data. The Ni 3 Sn 2 (ht) Ð Ni 3 Sn 2 (lt) transformation is discussed in terms of supergroup-subgroup relations. The bonding between the Ni and the Sn is discussed based on the analyses of the density of states (DOS) and the charge densities.

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Section: A Phase Stability Of Ni-sn Intermetallicsmentioning

confidence: 94%

Section: A Phase Stability Of Ni-sn Intermetallicsmentioning

confidence: 99%

First-Principles Calculation of Phase Stability and Cohesive Properties of Ni-Sn Intermetallics

Ghosh

2008

Metall Mater Trans A

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“…Therefore, based on the data on only the concentration induced expan sion, one cannot obtain information on the local ε loc 1 ( ) deformations. The calculated deviation from Vegard's law can be attributed to the transformation of the elec tronic structure with increasing alloying element con centration, which plays a significant role in the prop erties of these alloys [25].…”

Section: Discussionmentioning

confidence: 93%

Local deformations and chemical bonding in Fe-X (X = Si, Al, Ga, Ge) soft magnetic alloys

Petrik

Gornostyrev

2013

Phys. Metals Metallogr.

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Abstract-Dilute alloys based on ferromagnetic bcc iron modified by 3p (Al, Si) and 4p (Ga, Ge) elements are studied using the methods of the density functional theory. It is shown that the local deformations and solution energies depend on the position of an alloying element in the periodic system. The nature of Fe-X chemical bonding varies from weak metallic in Fe-Ga to strong quasi covalent in Fe-Si, which determines the values of local deformations in these alloys. The formation of pairs of impurity atoms in the position of the next nearest neighbors leads to tetragonal lattice deformations, the value of which is highest for Si and Ge. The role of local deformations in the formation of unusual magnetic properties of Fe-X alloys is dis cussed.

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“…Such a magnetic-moment-induced volume change is known as the magneto-volume effect. 21 Taking B as an example of the seven elastic properties under consideration, we evaluated the change in B induced by magnetic moments using Stoner's model of itinerant magnetism 22 and revealed that this model explains well the Si concentration dependence of B up to 9.4 at.%Si, but it cannot interpret the drastic change in B as the Si concentration increases above 9.4 at.%Si. 1 In the range of higher Si concentrations from 10.9 to 12.5 at.%Si, there should be another reason behind the recovery of the elastic properties as displayed in Fig.…”

Section: Elastic Propertiesmentioning

confidence: 99%

Mechanical properties of Fe-rich Si alloy from Hamiltonian

et al. 2017

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The physical origins of the mechanical properties of Fe-rich Si alloys are investigated by combining electronic structure calculations with statistical mechanics means such as the cluster variation method, molecular dynamics simulation, etc, applied to homogeneous and heterogeneous systems. Firstly, we examined the elastic properties based on electronic structure calculations in a homogeneous system and attributed the physical origin of the loss of ductility with increasing Si content to the combined effects of magneto-volume and D0 3 ordering. As a typical example of a heterogeneity forming a microstructure, we focus on grain boundaries, and segregation behavior of Si atoms is studied through high-precision electronic structure calculations. Two kinds of segregation sites are identified: looser and tighter sites. Depending on the site, different segregation mechanisms are revealed. Finally, the dislocation behavior in the Fe-Si alloy is investigated mainly by molecular dynamics simulations combined with electronic structure calculations. The solid-solution hardening and softening are interpreted in terms of two kinds of energy barriers for kink nucleation and migration on a screw dislocation line. Furthermore, the clue to the peculiar work hardening behavior is discussed based on kinetic Monte Carlo simulations by focusing on the preferential selection of slip planes triggered by kink nucleation.npj Computational Materials (2017) 3:10 ; doi:10.1038/s41524-017-0012-4 INTRODUCTION Mechanical properties of alloys originate from the behavior of electrons and atoms on the microscopic scale; however, the strength of atomic bonding does not directly relate to macroscopic mechanical properties such as the yield strength, fracture toughness, and fatigue resistance. This is because the microstructure on the mesoscale, which is composed of various defects such as impurities, grain boundaries, and dislocations, mediates or enhances the response of alloys against external forces, leading to fairly nonlinear and multiscale phenomena. Facing such a nonlinear nature associated with the strength and plastic deformation of alloys, identifying the controlling factors for the mechanical properties is a significantly difficult task, and clarifying the underlying physics at different length and time scales still remains a major challenge in materials science.The authors of the present article took up the challenge of this complicated problem with their particular theoretical and computational tools unique to each characteristic scale range. These tools are electronic structure calculations, the cluster variation method (CVM) of statistical mechanics, and molecular dynamics (MD) simulations, which may cover the atomic to mesoscopic scale ranges. By virtue of high-performance computers, some of the results obtained by the present calculations achieve a higher precision and reveal a clearer picture than those obtained by ordinary experiments.Among the various mechanical properties, the main focus of the present study is the solid-solut...

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Magnetism and origin of non-monotonous concentration dependence of the bulk modulus in Fe-rich alloys with Si, Ge and Sn: a first-principles study

Cited by 28 publications

References 30 publications

First-Principles Calculation of Phase Stability and Cohesive Properties of Ni-Sn Intermetallics

First-Principles Calculation of Phase Stability and Cohesive Properties of Ni-Sn Intermetallics

Local deformations and chemical bonding in Fe-X (X = Si, Al, Ga, Ge) soft magnetic alloys

Mechanical properties of Fe-rich Si alloy from Hamiltonian

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