Superhard Nanocrystalline Composites with Hardness of Diamond

Nesládek, Pavel; Vepřek, S.

doi:10.1002/(sici)1521-396x(200001)177:1<53::aid-pssa53>3.3.co;2-8

Cited by 13 publications

(15 citation statements)

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“…Such grains do not deform plastically; rather, they slide against each other to accommodate macroscopic strain imposed during mechanical deformation. From these results, it seems clear that the nature of the tissue phase and the crystallite/tissue-phase interface is fundamental to defining the macroscopic properties of nanocomposites such as TiN/Si 3 N 4 for which extraordinary mechanical properties including high hardness and fracture resistance have been reported [13,14].…”

Section: Introductionmentioning

confidence: 99%

Electronic structure of the SiNx/TiN interface: A model system for superhard nanocomposites

et al. 2011

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Section: Introductionmentioning

confidence: 99%

Electronic structure of the SiNx/TiN interface: A model system for superhard nanocomposites

et al. 2011

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“…Veprek et al 15 refer to such a microstructural contribution to hardness as extrinsic hardness. In this work, a superhardness of 45 GPa and 51 GPa was achieved for the room-temperature and 573 K-deposited AlMgB 14 films; however, it should be noted that such a high hardness was essentially obtained in an entirely amorphous structure, in which randomly distributed B 12 icosahedra dominate according to the FTIR results.…”

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confidence: 99%

Superhard self-lubricating AlMgB14 films for microelectromechanical devices

Tian

Bastawros

et al. 2003

Applied Physics Letters

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Performance and reliability of microelectromechanical system (MEMS) components can be enhanced dramatically through the incorporation of protective thin-film coatings. Current-generation MEMS devices prepared by the lithographie-galvanoformung-abformung (LIGA) technique employ transition metals such as Ni, Cu, Fe, or alloys thereof, and hence lack stability in oxidizing, corrosive, and/or high-temperature environments. Fabrication of a superhard self-lubricating coating based on a ternary boride compound AlMgB14 described in this letter has great potential in protective coating technology for LIGA microdevices. Nanoindentation tests show that the hardness of AlMgB14 films prepared by pulsed laser deposition ranges from 45 GPa to 51 GPa, when deposited at room temperature and 573 K, respectively. Extremely low friction coefficients of 0.04–0.05, which are thought to result from a self-lubricating effect, have also been confirmed by nanoscratch tests on the AlMgB14 films. Transmission electron microscopy studies show that the as-deposited films are amorphous, regardless of substrate temperature; however, analysis of Fourier transform infrared spectra suggests that the higher substrate temperature facilitates the formation of the B12 icosahedral framework, therefore leading to the higher hardness.

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“…In conventional metals, there is plenty of space for dislocations line defects the motion of which results in permanent material deformation to multiply so that the metal strengths are controlled by dislocation interactions with grain boundaries and other obstacles [7][8][9]. The unusual mechanical behaviour of nanocrystalline materials [10,11], showing either greatly enhanced ductility [12][13][14] or dramatically increased strength, hardness and ductility at room temperature [15][16][17][18], is thought to arise from the intricate interplay between dislocation, grain-boundary processes and sub-nanometre structures. It is well known that heavy deformations, e.g.…”

Section: Introductionmentioning

confidence: 99%

The effect of nanostructural hierarchy on the mechanical properties of aluminium alloys during deformation processes

Zhao

2012

J Mater Sci

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New generation of lightweight structures and technologies enables the development of materials to exhibit superior property combinations. In the present work, cellular automata is used to address the problem of dislocation behaviour and 4 factors: (i) a high density of dislocations, (ii) sub-nanometre intragranular solute clusters, (iii) 2 geometries of nanometre-scale intergranular solute structures and (iv) grain sizes tens of nanometres in diameter featuring in aluminium alloys containing a nanostructural hierarchy and exhibiting record strength with good ductility-an aerospace grade 7075 alloy exhibits a yield strength of 1 GPa and total elongation to failure of 9 %. We show that the clusters and geometries of nanometre-scale intergranular solute structures govern the strength of such material, resulting in their increasing elongation. Our results demonstrate that this simulation explains the phenomena of the super-strong materials of new generation with entirely new regimes of propertyperformance space.

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Superhard Nanocrystalline Composites with Hardness of Diamond

Cited by 13 publications

References 0 publications

Electronic structure of the SiNx/TiN interface: A model system for superhard nanocomposites

Electronic structure of the SiNx/TiN interface: A model system for superhard nanocomposites

Superhard self-lubricating AlMgB14 films for microelectromechanical devices

The effect of nanostructural hierarchy on the mechanical properties of aluminium alloys during deformation processes

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