Multi-walled carbon nanotubes reinforced Al2O3 nanocomposites: Mechanical properties and interfacial investigations

Ahmad, Iftikhar; Unwin, M. E.; Cao, Huatang; Chen, H.; Zhao, Haitao; Kennedy, Andrew R.; Zhu, Yan

doi:10.1016/j.compscitech.2010.03.007

Cited by 160 publications

(91 citation statements)

References 32 publications

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“…Fractography of the fracture surfaces of the composites revealed carbon based "bridges" between the alumina grains, which probably in the case of Al 2 O 3 -CNT composite are strong enough to increase the resistance against the crack propagation. These results are in good agreement with the results of recent investigations of Ahmad (Ahmad et al, 2010). There, well-dispersed CNT-reinforced Al 2 O 3 nanocomposites were prepared with reasonably high density using hot pressing.…”

Section: Hardness and Fracture Toughnesssupporting

confidence: 82%

Carbon Nanofibers Reinforced Ceramic Matrix Composites

Hvizdoš¹,

Puchý²,

Duszová³

et al. 2011

Nanofibers - Production, Properties and Functional Applications

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Section: Hardness and Fracture Toughnesssupporting

confidence: 82%

Carbon Nanofibers Reinforced Ceramic Matrix Composites

Hvizdoš¹,

Puchý²,

Duszová³

et al. 2011

Nanofibers - Production, Properties and Functional Applications

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“…These authors relate the observation of printed CNTs like stamps on the alumina grains with carbon diffusion into alumina lattice [26]. This idea suggests that the appearance of CNTs like a blanket coating the grains observed in these composites could be indicative of the presence of Al-C-O interphase between CNTs and alumina grains referred by [22,24]. with an elongated aspect of the matrix grains regardless the composition and orientation…”

Section: Microstructural Characterizationmentioning

confidence: 98%

“…In our case, this favorable sinterability suggests the presence of an effective diffusion layer bonding the SWNTs and the alumina grains. According to the sintering temperature used, the formation of an aluminum oxy-carbide phase (Al-O-C interphase among SWNTs and Al 2 O 3 grains) is possible [22,24]. Transgranular fracture zones are appreciated in composite C1, while the other composites mostly exhibit intergranular fracture.…”

mentioning

confidence: 99%

Improvement of Vickers hardness measurement on SWNT/Al2O3 composites consolidated by spark plasma sintering

Morales-Rodrı́guez

Gallardo-López

Fernández-Serrano

et al. 2014

Journal of the European Ceramic Society

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Dense alumina composites with different carbon nanotube content were prepared by colloidal processing and consolidated by Spark Plasma Sintering (SPS). Single-wall carbon nanotubes (SWNTs) were distributed at grain boundaries and also into agglomerates homogeneously dispersed. Carrying out Vickers hardness tests on the cross-section surfaces instead of top (or bottom) surfaces has shown a noticeable increase in the reliability of the hardness measurements. This improvement has been mainly attributed to the different morphology of carbon nanotube agglomerates, which however does not seem to affect the Vickers hardness value. Composites with lower SWNT content maintain the Vickers hardness of monolithic alumina, whereas it significantly decreases for the rest of compositions. The decreasing trend with increasing SWNT content has been explained by the presence of higher SWNT 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 Heterogeneous dispersion and distribution of CNTs in the ceramic matrix, poor chemical compatibility between CNTs and alumina hindering effective transfer load and the large differences in the scales of the matrix microstructure and the carbon nanotubes have been stated as main obstacles to transfer the desirable CNT mechanical properties to the brittle ceramic matrix [5,7,11,14,15]. Adequate dispersion of CNTs is very difficult owing to their tendency to form bundles in order to minimize their surface area.Although aqueous colloidal processing has been assessed as an efficient technique producing adequate dispersion of CNTs throughout ceramic matrix grain boundaries after sintering [18][19][20], the presence of agglomerates seems to be unavoidable.Recently, Poorteman et al [21] fabricated MWNT/alumina composites with low MWNT content (0.6 and 1.4 vol. %) by a colloidal processing route to optimize electrostatic

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“…Since Iijima's discovery in 1991 [6], a number of publications have been devoted to carbon nanotubes' material properties [7][8][9][10][11][12][13], strength (failure toughness) [14][15][16] and further application on composite materials [17][18][19][20][21]. Meanwhile, many researchers also focused on the nanocomposites composed of nanoparticles, e.g., silica (SiO 2 ), alumina (Al 2 O 3 ), titanium dioxide (TiO 2 ), etc., due to the greater reactive surface area per unit volume compared with large particles [22][23][24][25].…”

Section: Introductionmentioning

confidence: 99%

Applicability of Continuum Fracture Mechanics in Atomistic Systems

Cheng

Sun

2011

Volume 8: Mechanics of Solids, Structures and Fluids; Vibration, Acoustics and Wave Propagation

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Stress intensity factor is one of the most significant fracture parameters in linear elastic fracture mechanics (LEFM). Due to its simplicity, many researchers directly employed this concept to explain their results from molecular simulation. However, stress intensity factor defines the amplitude of the singular stress, which is the product of continuum elasticity. Under atomistic systems without the stress singularity, the concept of stress intensity factor must be examined. In addition, the difficulty of studying the stress intensity factor in atomistic systems may be traced back to the ambiguous definition of the local atomistic stress. In this study, the definition of the local virial stress is adopted. Subsequently, through the consideration of K-dominance, the approximated stress intensity factor based on the atomistic stress can be projected within a reasonable region. Moreover, the influence of cutting interatomic bonds to create traction free crack surfaces and the critical stress intensity factor is also discussed.

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Multi-walled carbon nanotubes reinforced Al2O3 nanocomposites: Mechanical properties and interfacial investigations

Cited by 160 publications

References 32 publications

Carbon Nanofibers Reinforced Ceramic Matrix Composites

Carbon Nanofibers Reinforced Ceramic Matrix Composites

Improvement of Vickers hardness measurement on SWNT/Al2O3 composites consolidated by spark plasma sintering

Applicability of Continuum Fracture Mechanics in Atomistic Systems

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