Correlation between hardness and elastic moduli of the ultraincompressible transition metal diborides RuB2, OsB2, and ReB2

Chung, Hsiu‐Ying; Weinberger, Michelle B.; Yang, Jenn‐Ming; Tolbert, Sarah H.; Kaner, Richard B.

doi:10.1063/1.2946665

Cited by 198 publications

(125 citation statements)

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“…3 and 4. This value is higher than those of RuB 2 (366 GPa), OsB 2 (410 GPa) and WB 4 (553 GPa) but lower than the value of 712 GPa reported for ReB 2 (15).…”

Section: Resultsmentioning

confidence: 41%

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Tungsten tetraboride, an inexpensive superhard material

Mohammadi

Lech

Xie

et al. 2011

Proc. Natl. Acad. Sci. U.S.A.

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Tungsten tetraboride (WB 4 ) is an interesting candidate as a less expensive member of the growing group of superhard transition metal borides. WB 4 was successfully synthesized by arc melting from the elements. Characterization using powder X-ray diffraction (XRD) and energy-dispersive X-ray spectroscopy (EDX) indicates that the as-synthesized material is phase pure. The zeropressure bulk modulus, as measured by high-pressure X-ray diffraction for WB 4 , is 339 GPa. Mechanical testing using microindentation gives a Vickers hardness of 43.3 AE 2.9 GPa under an applied load of 0.49 N. Various ratios of rhenium were added to WB 4 in an attempt to increase hardness. With the addition of 1 at.% Re, the Vickers hardness increased to approximately 50 GPa at 0.49 N. Powders of tungsten tetraboride with and without 1 at.% Re addition are thermally stable up to approximately 400°C in air as measured by thermal gravimetric analysis.dispersion hardening | indentation hardness | intrinsic hardness | nano-indentation hardness | solid solutions I n many manufacturing processes, materials must be cut, formed, or drilled, and their surfaces protected with wearresistant coatings. Diamond has traditionally been the material of choice for these shaping operations, due to its superior mechanical properties (e.g., hardness > 70 GPa) (1, 2). However, diamond is rare in nature and difficult to synthesize artificially due to the need for a combination of high temperature and high pressure. Industrial applications of diamond are thus generally limited by cost. Moreover, diamond is not a good option for high-speed cutting of ferrous alloys due to its graphitization on the material's surface and formation of brittle carbides, which leads to poor cutting performance (3). Other hard or superhard (hardness ≥ 40 GPa) substitutes for diamond include compounds of light elements such as cubic boron nitride (4) and BC 2 N (5) or transition metals combined with light elements such as WC (6), HfN (7), and TiN (8). Although the compounds of the first group (B, C, or N) possess high hardness, their synthesis requires high pressure and high temperature and is thus nontrivial (9, 10). On the other hand, most of the compounds of the second group (transition metal-light elements) are not superhard although their synthesis is more straightforward.To overcome the shortcomings of diamond and its substitutes, we have been pursuing the synthesis of dense transition metal borides, which combine high hardness with synthetic conditions that do not require high pressure (11,12). For example, arc melting and metathesis reactions have been used to synthesize the transition metal diborides OsB 2 (13, 14), RuB 2 (15), and ReB 2 (16-20). Among these, rhenium diboride (ReB 2 ) with a hardness of approximately 48 GPa under a load of 0.49 N has proven to be the hardest (16, 21). The boron atoms are needed to build the strong covalent metal-boron and boron-boron bonds that are responsible for the high hardness of these materials (12). Because of this, it is expected th...

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“…3 and 4. This value is higher than those of RuB 2 (366 GPa), OsB 2 (410 GPa) and WB 4 (553 GPa) but lower than the value of 712 GPa reported for ReB 2 (15).…”

Section: Resultsmentioning

confidence: 41%

“…3. The small pop-in events, observed in this figure, may be due to a burst of dislocations, elastic-plastic deformation transitions, or initiation and propagation of subsurface cracks (15). From this test, we estimate an elastic (Young's) modulus of 553 AE 14 GPa for WB 4 .…”

Section: Resultsmentioning

confidence: 85%

Tungsten tetraboride, an inexpensive superhard material

Mohammadi

Lech

Xie

et al. 2011

Proc. Natl. Acad. Sci. U.S.A.

Self Cite

315

281

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“…In sharp contrast to plenty of works on the correlations among the elastic moduli, the compressibility and the hardness in super-hard materials, 2,7,11 the study of Poisson's ratio (PR) and its effect on the hardness are largely neglected. The PR (v i j = − ε j/ε i ) is defined as the negative ratio between the induced transverse strain and the longitudinal strain for materials undergoing a deformation in the longitudinal direction.…”

Section: Introductionmentioning

confidence: 99%

“…The hardness is a complex parameter, which usually relies on elastic and plastic parameters such as the moduli (Young's modulus, bulk modulus and shear modulus), compressibility, ductility and viscosity. 1, [3][4][5][6][7][8][9][10] Usually, materials with a high bulk modulus tend to elastically resist volume compression, while materials possessing a high Young's modulus tend to elastically resist linear compression. Although there may be correlations among these moduli and the hardness for several particular classes of materials, the study of systematic dependence in super-hard materials is still at the primary stage.…”

Section: Introductionmentioning

confidence: 99%

Anisotropic elasticity and abnormal Poisson’s ratios in super-hard materials

Huang

Chen

2014

AIP Advances

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We theoretically investigated the variable mechanical properties such as Young's modulus, Poisson's ratios and compressibility in super-hard materials. Our tensorial analysis reveals that the mechanical properties of super-hard materials are strongly sensitive to the anisotropy index of materials. In sharp contrast to the traditional positive constant as thought before, the Poisson's ratio of super-hard materials could be unexpectedly negative, zero, or even positive with a value much larger than the isotropic upper limit of 0.5 along definite directions. Our results uncover a correlation between compressibility and hardness, which offer insights on the prediction of new super-hard materials. C

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“…On the other hand, d valence electrons are also considered to contribute to the hardness of TM compounds. According to this design criterion, many TM borides have been synthesized, such as ReB2 [5], OsB2 [6], RuB2 [7], YB4 [8], MnB4 [9][10][11], FeB4 [12], CrB4 [13,14] and son on. Also, WB4 with a hexagonal structure (P63/mmc, Z = 4) was synthesized at ambient pressure and was proposed to be a potential superhard material with the claimed hardness of 31.8-46.2 GPa [15].…”

Section: Introductionmentioning

confidence: 99%

Crystal Structure and Physical Properties of HfB4 via First-Principles Calculations

Zhang

Gao

Zhao

et al. 2017

Preprint

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By using the particle swarm optimization algorithm for crystal structure prediction, we reveal a newly orthorhombic Cmcm structure of HfB4, which is more energetically superior to the previously proposed YB4-, ReP4-, FeB4-, CrB4-, and MnB4-type structures in the considered pressure range. The phonon dispersion and elastic constants calculations confirm that the new phase is dynamically and mechanically stable. The calculated large shear modulus (240 GPa) and high hardness (45.7 GPa) imply that the predicted Cmcm-HfB4 is a potential superhard material. Meanwhile, the directional dependences of the Young's modulus, bulk modulus, and shear modulus for HfB4 are systematically investigated. Further analyses of the density of states and electronic localization function indicate that the strong B-B and B-Hf covalent bonds greatly contribute to its high hardness and stability.

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Correlation between hardness and elastic moduli of the ultraincompressible transition metal diborides RuB2, OsB2, and ReB2

Abstract: Mechanical and electronic properties of 5 d transition metal diborides M B 2 ( M = Re , W, Os, Ru) Hardness and elasticity in cubic ruthenium dioxide

Cited by 198 publications

References 22 publications

Tungsten tetraboride, an inexpensive superhard material

Tungsten tetraboride, an inexpensive superhard material

Anisotropic elasticity and abnormal Poisson’s ratios in super-hard materials

Crystal Structure and Physical Properties of HfB4 via First-Principles Calculations

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