First-principles study of the structural and elastic properties of rhenium-based transition-metal alloys

Jong, M. de; Olmsted, David L.; Walle, Axel van de; Asta, Mark

doi:10.1103/physrevb.86.224101

Cited by 27 publications

(13 citation statements)

References 59 publications

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“…In particular, the results suggest strategies for designing alloys that mimic the unique properties of Re by choosing combinations of alloying elements that lead to similar overall band fillings. Our findings thus have implications for ongoing research efforts towards finding effective substitutes to rhenium in high-temperature applications [60].…”

Section: H Y S I C a L R E V I E W L E T T E R S Week Ending 7 Augustmentioning

confidence: 78%

Electronic Origins of Anomalous Twin Boundary Energies in Hexagonal Close Packed Transition Metals

et al. 2015

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Density-functional-theory calculations of twin-boundary energies in hexagonal close packed metals reveal anomalously low values for elemental Tc and Re, which can be lowered further by alloying with solutes that reduce the electron per atom ratio. The anomalous behavior is linked to atomic geometries in the interface similar to those observed in bulk tetrahedrally close packed phases. The results establish a link between twin-boundary energetics and the theory of bulk structural stability in transition metals that may prove useful in controlling mechanical behavior in alloy design. DOI: 10.1103/PhysRevLett.115.065501 PACS numbers: 62.20.-x, 61.72.Mm Twinning is a common deformation mechanism in materials where the number of active dislocation slip systems is limited [1][2][3][4][5]. In such materials, understanding of the mechanisms underlying twin boundary (TB) formation can thus be essential for optimizing mechanical properties [6][7][8][9]. Theories of the crystallography of twinning and its relation to bulk deformation are well developed, and the mechanisms of twin nucleation and growth have been investigated in many technologically important systems [2]. However, the degree to which deformation twinning can be significantly influenced through variations in composition for materials design has been investigated in only a limited number of systems (see, e.g., Refs. [10][11][12][13]).In this Letter we report results of a study of the properties of commonly observed deformation twins in hexagonal close packed (hcp) structured transition metals, a class of materials that finds use in diverse applications including aerospace alloys, cladding for nuclear fuel, and magnetic recording. Through the use of density-functional-theory (DFT) calculations, we demonstrate anomalously low TB energies (γ t ) for the group VII transition metals, Re and Tc. This finding correlates with the unique mechanical properties of hcp structured Re, which displays pronounced deformation twinning [14][15][16][17], and a unique combination of high-temperature strength and low-temperature ductility [18] that have made it of interest for structural applications in extreme environments [18,19]. To investigate the electronic origins of this anomalous twinning behavior, we introduce a new method for computing the composition dependence of γ t in alloys. Results derived with this approach demonstrate that TB energies in Re can be decreased even further through alloying with elements that lower the average number of d electrons per atom relative to pure Re. These predictions are consistent with experimental characterization studies undertaken in this work, demonstrating pronounced differences in deformation microstructures in Re versus Re-10 at. % W alloys. The anomalous TB energetics in the group VII metals are correlated with the presence of structural units near the TB plane that are similar to the Frank-Kasper polyhedra characterizing the tetrahedrally close packed (TCP) transition metal intermetallic compounds that are stable near half d...

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Section: H Y S I C a L R E V I E W L E T T E R S Week Ending 7 Augustmentioning

confidence: 78%

Electronic Origins of Anomalous Twin Boundary Energies in Hexagonal Close Packed Transition Metals

et al. 2015

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“…The piezoelectric tensor reported in this work corresponds to a single crystal. For the elastic constants, polycrystalline isotropic averages of the bulk and shear constants can be derived from the single crystal 4th-order elastic tensor 35 , 70 , 71 . For the 3rd-order piezoelectric tensor, however, an isotropic averaging scheme is not convenient, as it will yield isotropic averages equal to zero 7 .…”

Section: Data Recordsmentioning

confidence: 99%

A database to enable discovery and design of piezoelectric materials

et al. 2015

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Piezoelectric materials are used in numerous applications requiring a coupling between electrical fields and mechanical strain. Despite the technological importance of this class of materials, for only a small fraction of all inorganic compounds which display compatible crystallographic symmetry, has piezoelectricity been characterized experimentally or computationally. In this work we employ first-principles calculations based on density functional perturbation theory to compute the piezoelectric tensors for nearly a thousand compounds, thereby increasing the available data for this property by more than an order of magnitude. The results are compared to select experimental data to establish the accuracy of the calculated properties. The details of the calculations are also presented, along with a description of the format of the database developed to make these computational results publicly available. In addition, the ways in which the database can be accessed and applied in materials development efforts are described.

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“…However, modelling the complex interplay between the host crystal, solutes, microstructure, and other defects requires a multiscale approach with information from smaller length-scale sim- 15 ulations informing mesoscale models. Density functional theory (DFT) calculations provide accurate information on solute effects in metals, and have determined solute-dislocation interactions [19,12], solute size misfits [19], and solute-dependent elastic stiffness coefficients [20,21,22,8]. Changes in lattice parameters and elastic stiffness coefficients can directly estimate solid-solution 20 strengthening parameters [23,24,3,19] and changes in ductility [25].…”

Section: Introductionmentioning

confidence: 99%

Ab initio calculations of the lattice parameter and elastic stiffness coefficients of bcc Fe with solutes

Fellinger

Hector

Trinkle

2017

Computational Materials Science

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We present an efficient methodology for computing solute-induced changes in lattice parameters and elastic stiffness coefficients C ij of single crystals using density functional theory. We introduce a solute strain misfit tensor that quantifies how solutes change lattice parameters due to the stress they induce in the host crystal. Solutes modify the elastic stiffness coefficients through volumetric changes and by altering chemical bonds. We compute each of these contributions to the elastic stiffness coefficients separately, and verify that their sum agrees with changes in the elastic stiffness coefficients computed directly using fully optimized supercells containing solutes. Computing the two elastic stiffness contributions separately is more computationally efficient and provides more information on solute effects than the direct calculations. We compute the solute dependence of polycrystalline averaged shear and Young's moduli from the solute dependence of the single-crystal C ij . We apply this methodology to substitutional Al, B, Cu, Mn, Si solutes and octahedral interstitial C and N solutes in bcc Fe. Comparison with experimental data indicates that our approach accurately predicts solute-induced changes in the lattice parameter and elastic coefficients. The computed data can be used to quantify solute-induced changes in mechanical properties such as strength and ductility, and can be incorporated into mesoscale models to improve their predictive capabilities.

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First-principles study of the structural and elastic properties of rhenium-based transition-metal alloys

Cited by 27 publications

References 59 publications

Electronic Origins of Anomalous Twin Boundary Energies in Hexagonal Close Packed Transition Metals

Electronic Origins of Anomalous Twin Boundary Energies in Hexagonal Close Packed Transition Metals

A database to enable discovery and design of piezoelectric materials

Ab initio calculations of the lattice parameter and elastic stiffness coefficients of bcc Fe with solutes

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