Particle reinforced nanocomposites, interfaces, strength and tribological properties depending on the reinforcement type
01 Jan 2020-pp 495-511
TL;DR: In this article, the development of the composites and the evaluation of different Graphene/SWCNT/MWCNT addition on the tribological properties, interfaces between the matrixes, reinforcement and sliding plate, microwear mechanism of developed nanocomposites.
Abstract: In recent days, the scope for particle reinforced metal matrix composites manufactured through powder metallurgy process has been intensified due to its remarkable blend of properties. Specifically, the enhanced tribological properties of metal matrix composites (MMCs) have paved way for using them in various fields including automotive, aerospace and other numerous applications. The processing methods of such MMCs are the becoming more challenging when considering smaller (nano range) particle as a reinforcement which requires advanced processing techniques. Carbon allotropes including graphene and CNT exist in nano-range are the unique material which are used to enhance various properties of nanocomposites. However, development of such materials is in initial stage due to lack of processing technique for specific applications. This needs to be channelized through integration of fabrication method along with the reinforcement selection and adding methods to meet the industrial demands. The processing technique and interfacial bonding of the matrix and reinforcement materials will define the final property of the component. This chapter focuses on the development of the composites and the evaluation of different Graphene/SWCNT/MWCNT addition on the tribological properties, interfaces between the matrixes, reinforcement and sliding plate, microwear mechanism of developed nanocomposites.
TL;DR: In this paper, the nano-sized particles with aluminium's matrix are strengthened with aluminum's matrix to produce Al-2.0%Al2O3 nano-composites and an experimental result shows noticeable improvement in tensile strength, yield strength and hardness.
TL;DR: A review of recent tribological studies based on graphene from the nano-scale to macro-scale, in particular, its use as a self-lubricating solid or as an additive for lubricating oils is provided in this paper.
TL;DR: In this article, three major mechanisms involved in CNT/Al composites are analyzed along with experimental procedure for making CNT and Al composites, along with three major composites strengthening mechanisms.
TL;DR: It is proposed that different degrees of direct mesothelial injury by thin and thick MWCNTs are responsible for the extent of inflammogenicity and carcinogenicity, and suggested that control of the diameter of M WCNTs could reduce the potential hazard to human health.
Abstract: Multiwalled carbon nanotubes (MWCNTs) have the potential for widespread applications in engineering and materials science. However, because of their needle-like shape and high durability, concerns have been raised that MWCNTs may induce asbestos-like pathogenicity. Although recent studies have demonstrated that MWCNTs induce various types of reactivities, the physicochemical features of MWCNTs that determine their cytotoxicity and carcinogenicity in mesothelial cells remain unclear. Here, we showed that the deleterious effects of nonfunctionalized MWCNTs on human mesothelial cells were associated with their diameter-dependent piercing of the cell membrane. Thin MWCNTs (diameter ∼ 50 nm) with high crystallinity showed mesothelial cell membrane piercing and cytotoxicity in vitro and subsequent inflammogenicity and mesotheliomagenicity in vivo. In contrast, thick (diameter ∼ 150 nm) or tangled (diameter ∼ 2-20 nm) MWCNTs were less toxic, inflammogenic, and carcinogenic. Thin and thick MWCNTs similarly affected macrophages. Mesotheliomas induced by MWCNTs shared homozygous deletion of Cdkn2a/2b tumor suppressor genes, similar to mesotheliomas induced by asbestos. Thus, we propose that different degrees of direct mesothelial injury by thin and thick MWCNTs are responsible for the extent of inflammogenicity and carcinogenicity. This work suggests that control of the diameter of MWCNTs could reduce the potential hazard to human health.
TL;DR: In this paper, a 1.0-wt.% graphene reinforced aluminum 6061 (Al6061) composite was synthesized to investigate the effects of graphene dispersion by ball milling technique.
Abstract: A 1.0 wt.% graphene reinforced aluminum 6061 (Al6061) composite was synthesized to investigate the effects of graphene dispersion by ball milling technique. The Al6061 powder and graphene were ball milled at different milling times. The composites were then synthesized by hot compaction in the semi-solid regime of the Al6061. A three point bending test was performed to characterize the mechanical properties of the composite. The ball milled powder and the fracture surfaces of the composites were analyzed using the scanning electron microscopy. A maximum enhancement of 47% in flexural strength was observed when compared with the reference Al6061 processed at the same condition.
TL;DR: In this paper, soundly aligned single-walled carbon nanotube (SWNT) ropes, synthesized by the catalytic decomposition of hydrocarbons, were employed for direct tensile strength measurements.
Abstract: 20 mm long ropes consisting of soundly aligned single-walled carbon nanotube (SWNT) ropes, synthesized by the catalytic decomposition of hydrocarbons, were employed for direct tensile strength measurements. The average tensile strength of SWNT rope composites is as high as 3.6 +/-0.4 GPa, similar to that of carbon fibers. The tensile strength of SWNT bundles was extrapolated from the strength of the composites to be 2.3 +/-0.2 to 14.2 +/-1.4 GPa after simply taking into account the volume fraction of SWNT bundles in the minicomposite, and the tensile strength of single SWNTs was estimated to be as high as 22.2 +/-2.2 GPa. The excellent mechanical properties of SWNTs will make them an ideal reinforcement agent for high performance composite materials. (C) 2000 American Institute of Physics. [S0003- 6951(00)00546-5].
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