Titanium diboride–silicon carbide–boron carbide ceramics with super‐high hardness and strength

Neuman, Eric W.; Brown-Shaklee, Harlan James; Hilmas, Greg

doi:10.1111/jace.15201

Cited by 41 publications

(19 citation statements)

References 22 publications

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“…Diborides (TMB 2 ) and transition metal tetraborides (TMB 4 ) have been widely investigated over the last years . However, the reported Vickers hardness of TMB 2 or TMB 4 is difficult to meet the requirement of superhard material . Naturally, the Vickers hardness of TMBs mainly relies on the shorter and network covalent bonds.…”

Section: Introductionmentioning

confidence: 99%

Influence of alloying elements on the mechanical and thermodynamic properties of ZrB₁₂ceramics from first‐principles calculations

Pan

Lin

2020

Int J of Quantum Chemistry

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Although ZrB 12 is a promising advanced material because of the boron cuboctahedron cages, the hardness of ZrB 12 remains controversy. Here, we apply first-principles calculations to study the influence of transition metals (4d-and 5d-) on the hardness and thermodynamic properties of ZrB 12 . The calculated hardness of ZrB 12 is 32.9 GPa, which is in good agreement with the previous theoretical result. Importantly, the calculated hardness of Re-doped ZrB 12 is up to 40.0 GPa, which is a potential superhard material. The essential reason is that the alloying element of Re enhances the localized hybridization of B B and Zr B atoms, and then forms the strong B B covalent bond and Zr B bond. The result is well demonstrated by the chemical bonding and lattice parameter. Here, our work shows that the alloying elements of Nb, Mo, and Re enhance the thermodynamic properties of ZrB 12 . The Debye temperature of Re-doped ZrB 12 is 1225.2 K, which is larger than that of the parent ZrB 12 (1213.5 K). K E Y W O R D S borides, elastic modulus, first-principles calculations, hardness, thermodynamic properties, ZrB 12 1 | INTRODUCTION Hard and superhard materials (≥40 GPa) are very important industrial materials, which are widely used in various industrial applications because of their high hardness, ultracompressibility, high melting point, and excellent thermal stability etc. [1-10] In comparison to diamond and boron nitride (c-BN), the transition metal borides (TMBs) are attractive potential superhard materials because of the network and shorter covalent bonding such as B B covalent bond and TM B bond. [11][12][13][14][15][16][17][18][19] Diborides (TMB 2 ) and transition metal tetraborides (TMB 4 ) have been widely investigated over the last years. [20][21][22][23][24] However, the reported Vickers hardness of TMB 2 or TMB 4 is difficult to meet the requirement of superhard material. [25][26][27][28][29] Naturally, the Vickers hardness of TMBs mainly relies on the shorter and network covalent bonds. In other words, the high concentration of boron plays a crucial role in Vickers hardness of TMBs. Among these TMBs, it is obvious that the transition metal dodecaborides (TMB 12 ) are potential superhard materials in comparison to TMB 2 and TMB 4 .Recently, ZrB 12 has evoked great interest because of the high concentration of boron and the network B B covalent bonds. [30] This dodecaboride is composed of the boron cuboctahedron cage (24 atoms) and 12-coordinate transition metals at the center of cubic structure. This structural feature is possible to enhance the Vickers hardness of TMBs. However, the Vickers hardness of ZrB 12 remains controversy. Korozlu et al. have found that the calculated Vickers hardness of ZrB 12 is 40.1 GPa, which is believed to a potential superhard material. [31] However, the recent works have shown that the Vickers hardness of ZrB 12 is 35.4 GPa by Chen et al. [32] and 29.3 GPa by Li et al., [33] which are different from Korozlu's result. On the other hand, even if the Vickers hardness of ZrB 12 remains...

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Section: Introductionmentioning

confidence: 99%

Influence of alloying elements on the mechanical and thermodynamic properties of ZrB₁₂ceramics from first‐principles calculations

Pan

Lin

2020

Int J of Quantum Chemistry

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“…7,11 The relative density of B 4 C-TiB 2 showed a decreasing tendency as the content of TiB 2 increased. 5,7,[12][13] As a consequence, the sintering additive was further introduced to improve the densification of B 4 C-TiB 2 system, including metallic addition, [14][15][16] oxides, [17][18] carbides, [19][20][21][22][23] borides, 24 etc. The addition of Mo and other metals, such as Fe, Co, and Ni, is favorable to form the liquid phase during sintering and thus improve the densification and mechanical properties of TiB 2 -based ceramics.…”

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Dense and core‐rim structured B₄C‐TiB₂ ceramics with Mo‐Co‐WC additive

et al. 2021

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B4C‐TiB2 ceramics (TiB2 ranging 5~70 vol%) with Mo‐Co‐WC as the sintering additive were prepared by spark plasma sintering. In comparison with B4C‐TiB2 without additive, the enhanced densification was evident in the sintered specimen with Mo‐Co‐WC additive. Core‐rim structured grain was observed around TiB2 grains. The interface of the rim between TiB2 and B4C phases demonstrated different feature: the inner borderline of the rim exhibited a smooth feature, whereas a sharp curved grain boundary was observed between the rim and the B4C grain. The formation mechanism is discussed: the epitaxial growth of (Ti,Mo,W)B2 rim around the TiB2 core may occur as a result of the solid solution and dissolution‐precipitation between TiB2 phase and the sintering additive. It was revealed that the fracture toughness increased as the content of TiB2 content increased, alongside the decreased hardness. B4C‐30 vol% TiB2 specimen demonstrated the optimal combination of mechanical properties, reaching Vickers hardness of 24.3 GPa and fracture toughness of 3.33 MPa·m1/2.

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“…3,8,9,14 Typically, these materials have been produced by hot pressing or spark plasma sintering of mixtures of a primary TM compound (e.g., ZrB 2 ) with a compound containing a second TM such as Mo, Ta, or W. Most reported diborides with core-shell microstructures also contain a source of silicon, such as SiC or a TM disilicide. 10,[15][16][17] Formation of the core-shell microstructure has been attributed to a transient liquid phase that forms due to the reaction of Si with residual surface oxides. 8,18,19 However, some studies have demonstrated the formation of core-shell materials in systems that do not contain Si, such as TiB 2 -WC and ZrB 2 -W, although core-shell formation was still attributed to liquid phase processes.…”

Section: Introductionmentioning

confidence: 99%

“…In core–shell microstructures, the solid solution shells can contain from 3 to 20 at% or more of the second TM 3,8,9,14 . Typically, these materials have been produced by hot pressing or spark plasma sintering of mixtures of a primary TM compound (e.g., ZrB 2 ) with a compound containing a second TM such as Mo, Ta, or W. Most reported diborides with core–shell microstructures also contain a source of silicon, such as SiC or a TM disilicide 10,15–17 …”

Section: Introductionmentioning

confidence: 99%

Solid‐state formation mechanisms of core–shell microstructures in (Zr,Ta)B₂ ceramics

2022

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Transition metal diborides with core-shell microstructures have demonstrated excellent mechanical properties at elevated temperatures. Previous studies concluded that core-shell microstructures were formed by liquid-assisted mass transport mechanisms, but in this study, we propose a solid-state formation mechanism for core-shell microstructures in (Zr,Ta)B 2 ceramics produced by reaction hot pressing and in ZrB 2 -TaB 2 diffusion couples. Diffusion couple experiments demonstrated that core-shell microstructures developed as a result of Ta diffusion along ZrB 2 grain boundaries, which occurred concurrently with lattice diffusion of Ta into ZrB 2 . These findings suggest that with optimization of batching and processing parameters, core-shell diboride materials may be formed through solid-state processes rather than liquid-assisted processes, which could assist in raising the upper temperature limits of use for these materials.

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Titanium diboride–silicon carbide–boron carbide ceramics with super‐high hardness and strength

Cited by 41 publications

References 22 publications

Influence of alloying elements on the mechanical and thermodynamic properties of ZrB₁₂ceramics from first‐principles calculations

Influence of alloying elements on the mechanical and thermodynamic properties of ZrB₁₂ceramics from first‐principles calculations

Dense and core‐rim structured B₄C‐TiB₂ ceramics with Mo‐Co‐WC additive

Solid‐state formation mechanisms of core–shell microstructures in (Zr,Ta)B₂ ceramics

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Titanium diboride–silicon carbide–boron carbide ceramics with super‐high hardness and strength

Cited by 41 publications

References 22 publications

Influence of alloying elements on the mechanical and thermodynamic properties of ZrB12ceramics from first‐principles calculations

Influence of alloying elements on the mechanical and thermodynamic properties of ZrB12ceramics from first‐principles calculations

Dense and core‐rim structured B4C‐TiB2 ceramics with Mo‐Co‐WC additive

Solid‐state formation mechanisms of core–shell microstructures in (Zr,Ta)B2 ceramics

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Influence of alloying elements on the mechanical and thermodynamic properties of ZrB₁₂ceramics from first‐principles calculations

Influence of alloying elements on the mechanical and thermodynamic properties of ZrB₁₂ceramics from first‐principles calculations

Dense and core‐rim structured B₄C‐TiB₂ ceramics with Mo‐Co‐WC additive

Solid‐state formation mechanisms of core–shell microstructures in (Zr,Ta)B₂ ceramics