The correlation between the electronic structure and elastic properties of nanolaminates

Mušić, Denis; Schneider, Jochen M.

doi:10.1007/s11837-007-0091-7

Cited by 75 publications

(54 citation statements)

References 79 publications

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“…We note that analogous arrangements of electrons, in layered structures, have been used to explain the high bulk moduli and low C 44 constants reported for a number of MAX phases and nanolaminates 40 and connected to the malleability of these materials. The difference is that the electronic layered structure reported herein is induced by the deformation, compared to the de facto, existing layering of electrons in MAX phases.…”

Section: Resultsmentioning

confidence: 84%

Electronic mechanism for toughness enhancement inTixM1−xN(M=M

2010

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Toughness, besides hardness, is one of the most important properties of wear-resistant coatings. We use ab initio density-functional theory calculations to investigate the mechanical properties of ternary metal nitrides Ti x M 1−x N, with M = Mo and W, for x = 0.5. Results show that Mo and W alloying significantly enhances the toughness of TiN. The electronic mechanism responsible for this improvement, as revealed by electronic structure calculations, stems from the changes in charge density induced by the additional transition-metal atom. This leads to the formation of a layered electronic arrangement, characterized by strong, respectively, weak, directional bonding, which enables a selective response to strain, respectively, shear, deformations of the structures and yields up to 60% decrease in C 44 values.

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Section: Resultsmentioning

confidence: 84%

Electronic mechanism for toughness enhancement inTixM1−xN(M=M

2010

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“…Music and Schneider [96] proposed that nanolaminates can be generally described as interleaved layers of high and low electron density, within a single unit cell. This description applies to the MAX phases, but also to many other phases with an inherently nanolaminated structure (cf.…”

Section: Related Inherently Nanolaminated Phasesmentioning

confidence: 99%

“…section 2.1.3.1), such as Al 3 BC 3 , Zr 2 Al 3 C 5 , W 2 B 5 -based phases, cubic perovskite borides, and Y n+1 Co 3n+5 B 2n (n=1, 2, 3,…), as reviewed in Ref. 96. Recent progress in research on inherently nanolaminated ternary carbides in the Zr-Al-C and Hf-Al-C systems, including their relation to the MAX phases, were recently reviewed by Wang and Zhou [97].…”

Section: Related Inherently Nanolaminated Phasesmentioning

confidence: 99%

The M+1AX phases: Materials science and thin-film processing

et al. 2010

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This article is a critical review of the M n+1 AX n phases ("MAX phases", where n =1, 2, or 3) from a materials science perspective. MAX phases are a class of hexagonal-structure ternary carbides and nitrides ("X") of a transition metal ("M") and an A-group element. The most well known are Ti 2 AlC, Ti 3 SiC 2 , and Ti 4 AlN 3 . There are ~60 MAX phases with at least 9 discovered in the last five years alone. What makes the MAX phases fascinating and potentially useful is their remarkable combination of chemical, physical, electrical, and mechanical properties, which in many ways combine the characteristics of metals and ceramics. For example, MAX phases are typically resistant to oxidation and corrosion, elastically stiff, but at the same time they exhibit high thermal and electrical conductivities and are machinable. These properties stem from an inherently nanolaminated crystal structure, with M n+1 X n slabs intercalated with pure A-element layers. The research on MAX phases has been accelerated by the introduction of thin-film processing methods.Magnetron sputtering and arc deposition have been employed to synthesize single-crystal material by epitaxial growth, which enables studies of fundamental materials properties. However, the surface-initiated decomposition of M n+1 AX n thin films into MX compounds at temperatures of 1000-1100 °C is much lower than the decomposition temperatures typically reported for the corresponding bulk material. We also review the prospects for low-temperature synthesis, which is essential for deposition of MAX phases onto technologically important substrates. While deposition of MAX phases from the archetypical Ti-Si-C and Ti-Al-N systems typically require synthesis temperatures of ~800 °C, recent results have demonstrated that V 2 GeC and Cr 2 AlC can be deposited at ~450 °C. Also, thermal spray of Ti 2 AlC powder has been used to produce thick coatings. We further treat progress in the use of first-principles calculations for predicting hypothetical MAX phases and their properties. Together with advances in processing and materials 3 analysis, this progress has led to recent discoveries of numerous new MAX phases such as Ti 4 SiC 3 , Ta 4 AlC 3 , and Ti 3 SnC 2 . Finally, important future research directions are discussed. These include charting the unknown regions in phase diagrams to discover new equilibrium and metastable phases, as well as research challenges in understanding their physical properties, such as the effects of anisotropy, impurities, and vacancies on the electrical properties, and unexplored properties such as superconductivity, magnetism, and optics. 4

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“…The input lattice parameters of the M 2 SbP studied are taken from Reference [17] and those of MP in the Hexagonal structure as well as TiSb alloy, which are used for the comparison purposes, can be found in References [34,35]. …”

Section: Methodology and Computational Detailsmentioning

confidence: 99%

“…Experimentally, H. Boller [15], synthesized this compound by power sintering at 800˚C. Theoretically, D. Music and co-workers [16] investigated the chemical bonding and elastic properties of this compound and the correlation between the electronic structure and elastic properties of nanolaminates ternary phosphides [17] using ab initio calculation.…”

Section: Introductionmentioning

confidence: 99%