Optimization of thermal stability and mechanical properties of Mo2C carbides via multi-element doping: experimental and theoretical calculations

Sun, Chichi; Zheng, Yong; Fang, Feng; Tu, Yiyou; Jiang, Jianqing; Zhou, Xuefeng

doi:10.1007/s10853-022-07693-9

Cited by 3 publications

(1 citation statement)

References 46 publications

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“…Close values were measured for nanocomposite thin films deposited at a higher power of the carbon target in this study. Furthermore, it should be noted that theoretical calculations demonstrated that doping molybdenum carbide with W resulted in enhanced mechanical modulus and elastic anisotropy; however, the effect on the hardness was negligible [ 61 , 62 ]. Hence, the enhancement of hardness was likely to be attributed to the nanocomposite nature of the deposited Mo-W-C films, i.e., a combination of hard carbide nanocrystallites with different strictures embedded into an amorphous carbon matrix [ 63 ].…”

Section: Resultsmentioning

confidence: 99%

Microstructural, Electrical, and Tribomechanical Properties of Mo-W-C Nanocomposite Films

Smyrnova,

Ivashchenko,

Sahul

et al. 2024

Nanomaterials

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This study investigates the phase composition, microstructure, and their influence on the properties of Mo-W-C nanocomposite films deposited by dual-source magnetron sputtering. The synthesised films consist of metal carbide nanograins embedded in an amorphous carbon matrix. It has been found that nanograins are composed of the hexagonal β-(Mo2 + W2)C phase at a low carbon source power. An increase in the power results in the change in the structure of the carbide nanoparticles from a single-phase to a mixture of the β-(Mo2 + W2)C and NaCl-type α-(Mo + W)C(0.65≤k≤1) solid-solution phases. The analysis of electrical properties demonstrates that the nanograin structure of the films favours the occurrence of hopping conductivity. The double-phase structure leads to a twofold increase in the relaxation time compared to the single-phase one. Films with both types of nanograin structures exhibit tunnelling conductance without the need for thermal activation. The average distance between the potential wells produced by the carbide nanograins in nanocomposite films is approximately 3.4 ± 0.2 nm. A study of tribomechanical properties showed that Mo-W-C films composed of a mixture of the β-(Mo2 + W2)C and α-(Mo + W)C(0.65≤k≤1) phases have the highest hardness (19–22 GPa) and the lowest friction coefficient (0.15–0.24) and wear volume (0.00302–0.00381 mm2). Such a combination of electrical and tribomechanical properties demonstrates the suitability of Mo-W-C nanocomposite films for various micromechanical devices and power electronics.

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Section: Resultsmentioning

confidence: 99%

Microstructural, Electrical, and Tribomechanical Properties of Mo-W-C Nanocomposite Films

Smyrnova,

Ivashchenko,

Sahul

et al. 2024

Nanomaterials

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Study on Evolution Behavior of Carbides in Industrial‐Grade American Iron and Steel Institute M35 High‐Speed Steel Produced by Electroslag Remelting

Liang,

Li,

et al. 2024

steel research int.

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In order to optimize the heating schedule before forging and improve the breaking and deformation effects of carbides in high‐speed steel, it is of great significance to study the transformation of M2C carbides at high temperatures. The evolution of carbides in the industrial‐grade American Iron and Steel Institute M35 steel produced by electroslag remelting (ESR) is analyzed and observed using thermodynamic calculations and experimental methods. The results indicate that the carbides in the ESR ingot are mainly MC and M2C, and the microstructures of M2C carbides with the highest volume fraction are lamellar and brain like. As the heating temperature increases and holding time prolongs, the lamellar M2C carbides gradually transform into MC and M6C carbides, accompanied by protrusion, dissolution, separation, and spheroidization of the microstructure, until significant coarsening occurs at 1180 °C for 90 min. The newly transformed carbides are embedded and stacked with each other, occupying the original position of M2C carbides. Based on the theories of Gibbs free energy and atomic diffusion, the evolution mechanism of M2C carbides is discussed. Ultimately, the appropriate heating schedule is proposed, and it is validated by combining the characteristics of carbides after forging.

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First-Principles Calculation and Analysis of the Magnetic and Mechanical Properties of Mo2C with Vacancy Defects and Substitutional Doping

Qing,

Guo,

Liu

et al. 2024

Crystals

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In this study, the first-principles method is adapted to establish key data for β-Mo2C with various point defects. A particular focus is comparatively studying the effects of point vacancies and different substitutional doping elements on the structures and electronic, magnetic and mechanical properties of β-Mo2C. The calculation results show that vacancy defects and substitutional doping have different impacts on the magnetism and bulk modulus of Mo2C. Data for the effect of different substitutional doping elements (V, Cr, Co, Fe, Ni and W) on the physical and mechanical properties/behaviours are established and analysed. The changes in key magnetic properties (local and total magnetic moments) associated with different point substitutional doping elements are comparatively analysed with reference to the data of Mulliken atomic charge, bond population, density of states (DOS) and band structures. The correlation between doping elements and changes in magnetic moment and bulk modulus is discussed. The influence of doping elements on the magnetic moment of 3D Mo2C is also compared to their effects on a two-dimensional Mo2C monolayer. The potential applications of DFT modeling and data for future research and development related to materials and processing are discussed.

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Optimization of thermal stability and mechanical properties of Mo2C carbides via multi-element doping: experimental and theoretical calculations

Cited by 3 publications

References 46 publications

Microstructural, Electrical, and Tribomechanical Properties of Mo-W-C Nanocomposite Films

Microstructural, Electrical, and Tribomechanical Properties of Mo-W-C Nanocomposite Films

Study on Evolution Behavior of Carbides in Industrial‐Grade American Iron and Steel Institute M35 High‐Speed Steel Produced by Electroslag Remelting

First-Principles Calculation and Analysis of the Magnetic and Mechanical Properties of Mo2C with Vacancy Defects and Substitutional Doping

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