First-principles study of the elastic properties of and alloys

Tu, Yufei; Wang, Yuanxu

doi:10.1016/j.ssc.2010.11.023

Cited by 25 publications

(13 citation statements)

References 14 publications

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“…However, very few studies have been conducted on the mechanical properties of these materials. In recent years, the hardness values of hexagonal of ternary borides Os 1‐x Re x B 2 , Os 1‐x W x B 2 and Re 1‐x W x B 2 , etc., were estimated by first‐principle calculations, which suggested that the hardness of these materials can be higher than 40 GPa . Experimental studies by Gu et al showed that Os 0.5 W 0.5 B 2 could have a thermally stable ReB 2 ‐type hexagonal structure with a hardness of 40.4 GPa under the applied load of 0.49N, which was in excellent agreement with the calculated value of 40.1 GPa .…”

Section: Introductionsupporting

confidence: 69%

Effects of Re addition on phase stability and mechanical properties of hexagonal OsB₂

et al. 2017

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ReB 2 -type hexagonal Osmium diboride (OsB 2 ) has been predicted to exhibit higher hardness than its orthorhombic phase, but hexagonal-orthorhombic phase transformation occurs at temperature higher than 600°C, resulting in the decrease in its hardness. Therefore, ReB 2 -type hexagonal OsB 2 samples with Re addition were produced by a combination of mechanochemical method and pressureless sintering technique, and the effects of Rhenium (Re) addition on phase composition, thermal stability and mechanical properties of OsB 2 were investigated in this study. X-ray diffraction (XRD) analysis of the as-synthesized powders by high-energy ball milling indicates the formation of hexagonal Os 1-x Re x B 2 solid solution with Re concentration of 5 and 10 at.% without forming a second phase. After being sintered at 1700°C, part of the hexagonal phase in OsB 2 transformed to orthorhombic structure, while Os 0.95 Re 0.05 B 2 and Os 0.9 Re 0.1 B 2 maintained their hexagonal structure. This suggests that the thermal stability of the hexagonal OsB 2 was significantly improved with the addition of Re. Scanning electron microscopy (SEM) photographs show that all of the as-sintered samples exhibit a homogeneous microstructure with some pores and cracks formed throughout the samples with the relative density >90%. The measurements of micro-hardness, nano-hardness, and Young's modulus of the OsB 2 increased with Re addition, and these properties of the sample with 5 at.% addition of Re is higher than that with 10 at.% Re. K E Y W O R D Shardness, Os 1-x Re x B 2 , phase composition, thermal stability | INTRODUCTIONSuper-hard materials, due to their high hardness, high bulk modulus and high wear resistance, are widely used in machining, construction, aerospace, processing of new materials, automobile, and other fields.1 Conventional super-hard materials, e.g., diamond and c-BN, have been considered as the best option for fulfilling industrial machining requirements. 2-4 However, diamond cannot effectively machine steel or other ferrous metals due to the tendency to form iron carbide at elevated temperatures. c-BN would cut these ferrous materials, but it must be synthesized under high-pressure and high-temperature conditions, which makes it very expensive. To overcoming these shortcomings, it is highly desirable to develop new class of super-hard materials. 5During the past decade, efforts have been devoted to design and synthesis new super-hard materials for both scientific and practical application purposes. Recent searches on new super-hard materials mainly focus on two classes

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Section: Introductionsupporting

confidence: 69%

Effects of Re addition on phase stability and mechanical properties of hexagonal OsB₂

et al. 2017

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“…Additionally, since our original identification of superhardness in ReB 2 , an increasingly large number of theoretical works have appeared in the literature with calculations of hardness using first-principles methods for metal borides of this type. − Several of these works have made claims to predict the already measured and reported properties of previously synthesized materials, but there are few examples of true predictions followed by experimental validation. Therefore, it is as yet unclear to what extent the experimentalist might find these sorts of calculations to be a useful guidance for the creation of new compounds with reliably predetermined properties and to what extent these works represent post hoc rationalization of properties that have already been determined.…”

Section: Introductionmentioning

confidence: 99%

Superhard Rhenium/Tungsten Diboride Solid Solutions

Lech¹,

Turner²,

Lei³

et al. 2016

J. Am. Chem. Soc.

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Rhenium diboride (ReB), containing corrugated layers of covalently bonded boron, is a superhard metallic compound with a microhardness reaching as high as 40.5 GPa (under an applied load of 0.49 N). Tungsten diboride (WB), which takes a structural hybrid between that of ReB and AlB, where half of the boron layers are planar (as in AlB) and half are corrugated (as in ReB), has been shown not to be superhard. Here, we demonstrate that the ReB-type structure can be maintained for solid solutions of tungsten in ReB with tungsten content up to a surprisingly large limit of nearly 50 atom %. The lattice parameters for the solid solutions linearly increase along both the a- and c-axes with increasing tungsten content, as evaluated by powder X-ray and neutron diffraction. From micro- and nanoindentation hardness testing, all of the compositions within the range of 0-48 atom % W are superhard, and the bulk modulus of the 48 atom % solid solution is nearly identical to that of pure ReB. These results further indicate that ReB-structured compounds are superhard, as has been predicted from first-principles calculations, and may warrant further studies into additional solid solutions or ternary compounds taking this structure type.

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“…In the total DOS of Ti 5 X 3 (X¼Si, Ge, Sn, Pb), the most important feature is the presence of a valley near the Fermi level, and this valley is referred to as a pseudogap. The pseudogap may indicate the presence of covalent bonding in Ti 5 X 3 (X¼Si, Ge, Sn, Pb) [46]. Furthermore, with increase of the atomic number of the group-IVA element X, d and p states of X element contribute more to the DOS near the Fermi level, and the pseudogap is narrower and shallower, the Fermi level is deviated from the bottom of the pseudogap.…”

Section: Electronic Structurementioning

confidence: 99%

Elastic and electronic properties of the Ti5X3 (X=Si, Ge, Sn, Pb) compounds from first-principles calculations

Chen¹,

Mo²,

Wang³

et al. 2012

Journal of Solid State Chemistry

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First-principles study of the elastic properties of and alloys

Cited by 25 publications

References 14 publications

Effects of Re addition on phase stability and mechanical properties of hexagonal OsB₂

Effects of Re addition on phase stability and mechanical properties of hexagonal OsB₂

Superhard Rhenium/Tungsten Diboride Solid Solutions

Elastic and electronic properties of the Ti5X3 (X=Si, Ge, Sn, Pb) compounds from first-principles calculations

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First-principles study of the elastic properties of and alloys

Cited by 25 publications

References 14 publications

Effects of Re addition on phase stability and mechanical properties of hexagonal OsB2

Effects of Re addition on phase stability and mechanical properties of hexagonal OsB2

Superhard Rhenium/Tungsten Diboride Solid Solutions

Elastic and electronic properties of the Ti5X3 (X=Si, Ge, Sn, Pb) compounds from first-principles calculations

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Effects of Re addition on phase stability and mechanical properties of hexagonal OsB₂

Effects of Re addition on phase stability and mechanical properties of hexagonal OsB₂