Strengthening and toughening of carbon nanotube reinforced alumina nanocomposite fabricated by molecular level mixing process

Seung, I.; Kim, Kyung Taec; Lee, Kyong H.; Mo, Chan Bin; Hong, Soon Hyung

doi:10.1016/j.scriptamat.2005.06.011

Cited by 225 publications

(117 citation statements)

References 14 publications

Supporting

Mentioning

103

Contrasting

Unclassified

Order By: Relevance

“…It should be noted that, in our composites, peak K IC values were obtained at 0.25-0.5 vol% of graphene, which is contrast to the previous works on carbon nanotube (CNT)/alumina composites [3][4][5][6][7][8] or whisker-reinforced alumina [16][17][18] . The CNT/alumina composite usually showed the greatest improvement in fracuture toughness at 1 , 10 vol% CNT concentration and whisker-reinforced alumina at .10 vol% 35 .…”

Section: Discussioncontrasting

confidence: 98%

“…single-layer graphene ,2630 m 2 / g), surprisingly small amounts of graphene would be enough to satisfy complete coverage of precursor nanoparticles (less than 1.0 vol%). In the case of carbon nanotube (CNT), it has been reported that higher reinforcement concentration (1 , 10 vol%) was generally required for the toughening and strengthening of CNT/ceramic composites [2][3][4][5][6][7][8] . Moreover, graphene is a good candidate for solid lubrication that reduces the friction force between contact surfaces at micro-and nano-scale while protecting the coated surface [9][10] .…”

mentioning

confidence: 99%

“…Wear-resistant (contact-mechanical) applications, which are successfully commercialized to a greater extent than structural ceramics, still have a problem due to their brittleness when wear conditions are severe. In order to overcome those problems, a variety of ceramic composites that are reinforced with fibres 15 , carbon nanotubes (CNTs) [2][3][4][5][6][7][8] , or whiskers [16][17][18] , have been considered to date. Still, a large amount of reinforcement material (e.g., for SiC , 20 vol%) and high-pressure-sintering have been required to obtain sufficient density to achieve a 'high' fracture toughness (.5.5 MPa?m 1/2 ) in such CMCs (e.g.…”

mentioning

confidence: 99%

See 2 more Smart Citations

Percolative Electrical Conductivity of Platy Alumina/Few-layer Graphene Multilayered Composites

Choi¹,

Kim²,

Lee³

et al. 2017

J. Korean Ceram. Soc

View full text Add to dashboard Cite

It is of critical importance to improve toughness, strength, and wear-resistance together for the development of advanced structural materials. Herein, we report on the synthesis of unoxidized graphene/alumina composite materials having enhanced toughness, strength, and wear-resistance by a low-cost and environmentally benign pressure-less-sintering process. The wear resistance of the composites was increased by one order of magnitude even under high normal load condition (25 N) as a result of a tribological effect of graphene along with enhanced fracture toughness (K IC ) and flexural strength (s f ) of the composites by ,75% (5.60 MPa?m 1/2 ) and ,25% (430 MPa), respectively, compared with those of pure Al 2 O 3 . Furthermore, we found that only a small fraction of ultra-thin graphene (0.25-0.5 vol%, platelet thickness of 2-5 nm) was enough to reinforce the composite. In contrast to unoxidized graphene, graphene oxide (G-O) and reduced graphene oxide (rG-O) showed little or less enhancement of fracture toughness due to the degraded mechanical strength of rG-O and the structural defects of the G-O composites.A tomically thin graphene is one of the strongest materials; therefore, it is promising as a toughening/ strengthening agent in ceramic-based structural materials 1 . Smaller nano-scale graphene, compared to conventional whisker/fiber reinforcement, would induce smaller flaws, potentially resulting in higher strength/toughness 2 . Considering the enormous surface area of graphene (e.g. single-layer graphene ,2630 m 2 / g), surprisingly small amounts of graphene would be enough to satisfy complete coverage of precursor nanoparticles (less than 1.0 vol%). In the case of carbon nanotube (CNT), it has been reported that higher reinforcement concentration (1 , 10 vol%) was generally required for the toughening and strengthening of CNT/ceramic composites [2][3][4][5][6][7][8] . Moreover, graphene is a good candidate for solid lubrication that reduces the friction force between contact surfaces at micro-and nano-scale while protecting the coated surface [9][10] . A nanometer-thick surface layer of hard, strong, and lubricating graphene on ceramic grains can lead to a significant improvement in contact-damage resistance, such as wear resistance due to a tribological effect of 2-dimensional (2D) graphene. However, previous studies on graphene tribology have focused on nano-scale friction and wear behavior (normal load ,250 mN) [9][10][11] . On the other hand, micro-/macro-scale tribological studies of graphene have remained relatively unexplored, but there is an increasing need to utilize graphene's full potential for diverse tribological applications. There has been no report on the friction and wear behavior of ceramic-based graphene composites in micro-and macro-scale under high normal load (.20 N), which is important for contact-mechanical applications (e.g. bearing, valves, nozzles, armour, prostheses) and protective coating applications.Structural materials for extreme environments (e.g. high temperature/press...

show abstract

Section: Discussioncontrasting

confidence: 98%

mentioning

confidence: 99%

mentioning

confidence: 99%

See 1 more Smart Citation

Percolative Electrical Conductivity of Platy Alumina/Few-layer Graphene Multilayered Composites

Choi¹,

Kim²,

Lee³

et al. 2017

J. Korean Ceram. Soc

View full text Add to dashboard Cite

show abstract

“…This nullifies the effect of fine alumina grains produced by the presence of CNTs at the grain boundaries of the composite. Some papers have reported no effect [28] or improved hardness [5,[29][30][31] by the incorporation of CNTs. However, the improvements were marginal and no comments were presented on the interfacial interactions between hard ceramic particles and the lubricating CNTs.…”

Section: Introductionmentioning

confidence: 99%

The production of advanced fine-grained alumina by carbon nanotube addition

Inam

Peijs

Reece

2011

Journal of the European Ceramic Society

View full text Add to dashboard Cite

Alumina and alumina+1vol.% carbon nanotube (CNT) composites were fully densified by spark plasma sintering. Post-sintering heat treatments (1300-1500 •C) were performed to completely oxidize CNTs and then densify the remaining 1 vol.% to produce fine-grained ceramics. The grain size and Vickers hardness of the heat-treated composites were compared with the monolithic alumina sintered without CNT addition. Compared to the initial powder particle size of alumina (D50: 356±74 nm), minimal grain growth (∼450 nm) was observed for the fully dense heat-treated composites. A 25% improvement in Vickers hardness and >10 times finer average grain size were observed for alumina produced by the heat treatment (1300 •C) of alumina+1vol.% CNT composite, compared to alumina sintered without CNTs. Alumina and alumina + 1 vol.% carbon nanotube (CNT) composites were fully densified by spark plasma sintering. Post-sintering heat treatments (1300 -1500 o C) were performed to completely oxidize CNTs and then densify the remaining 1 vol.% to produce fine-grained ceramics. The grain size and Vickers hardness of the heat-treated composites were compared with the monolithic alumina sintered without CNT addition. Compared to the initial powder particle size of alumina (D 50 : 356 nm ± 74 nm), minimal grain growth (~450 nm) was observed for the fully dense heat-treated composites. A 25% improvement in Vickers hardness and >10 times finer average grain size were observed for alumina produced by the heat treatment (1300 o C) of alumina + 1 vol.% CNT composite, compared to alumina sintered without CNTs. Introduction

show abstract

“…Most of the current Al-CNT composites were fabricated by P/M and significant enhancement in stiffness and strength have been obtained [4][5][6]. A novel method to fabricate CNT-Al composites, which consists of a molecular level mixing process was proposed Cha et al [7]. The CNT-Al metal matrix composites fabricated by this process improved the hardness due to a load transfer mechanism of the CNTs.…”

Section: Introductionmentioning

confidence: 99%

Bending Analysis of CNT Reinforced Metal Matrix Composite Rectangular Plates Using Higher Order Shear Deformation Theory

Patel¹

2017

IJRASET

View full text Add to dashboard Cite

I. INTRODUCTIONThe immense need to develop lightweight and high-strength materials for improving energy-efficiency through the weight reduction of transportation carriers. Metal matrix composites (MMCs) generally consist of lightweight metal alloys of aluminum magnesium, or titanium, reinforced with ceramic particulate, whiskers, or fibres. The reinforcement is very important because it determines the mechanical properties, cost, and performance of a given composite. Composites reinforced with particulate (discontinuous types of reinforcement) can have costs to unreinforced metals, with significantly better hardness, and somewhat better stiffness and strength. Continuous reinforcement (long fibre) can result in dramatic improvements in mechanical properties of MMC, but costs remain high. The application of continuously and discontinuously reinforced MMCs varies based on the design requirements. MMCs can be tailored to fulfil requirements that no other materials, including other advanced materials, can achieve. There are a number of niche applications in aerospace structures and electronics that capitalize on this advantage. Aluminium and its alloys have attracted many researchers to choose it as a base metal in metal matrix composites [1]. Aluminium MMCs are widely used in aircraft, aerospace, automobiles and various other fields [2].Al matrix is widely used for CNT reinforced MMCs. Since the work by Zhong et al. [3]. The reinforcements should be stable in the given working temperature and non-reactive too. There are many manufacturing methods to obtain the CNT reinforced Al matrix composites (Al-CNT), amongst which, the powder metallurgy (P/M) technique could be considered as the most effective and economic one. Most of the current Al-CNT composites were fabricated by P/M and significant enhancement in stiffness and strength have been obtained [4][5][6]. A novel method to fabricate CNT-Al composites, which consists of a molecular level mixing process was proposed Cha et al. [7]. The CNT-Al metal matrix composites fabricated by this process improved the hardness due to a load transfer mechanism of the CNTs. The strength of CNT-Al metal matrix composites and investigated the relevant strengthening mechanisms involved in CNT-Al composites in order to produce optimized composites was studied George et al. [8]. The need for high performance and lightweight materials for some demanding applications has led to extensive efforts in the development of aluminium matrix composites and cost-effective fabrication technologies [9][10][11][12]. They are proved to have good mechanical properties through an incorporation of structural filler (e.g., aluminium oxide, ceramic whiskers such as silicon carbide whisker and others, graphite, carbon fibers and CNTs) With this context, the dimensionally Nano-sized, mechanically strong CNTs [13][14][15][16] are considered as the ideal reinforcing filler in various composite systems [17][18][19][20], have been incorporated into aluminium

show abstract

Strengthening and toughening of carbon nanotube reinforced alumina nanocomposite fabricated by molecular level mixing process

Cited by 225 publications

References 14 publications

Percolative Electrical Conductivity of Platy Alumina/Few-layer Graphene Multilayered Composites

Percolative Electrical Conductivity of Platy Alumina/Few-layer Graphene Multilayered Composites

The production of advanced fine-grained alumina by carbon nanotube addition

Bending Analysis of CNT Reinforced Metal Matrix Composite Rectangular Plates Using Higher Order Shear Deformation Theory

Contact Info

Product

Resources

About