Reinforcing effects of carbon nanotubes in structural aluminum matrix nanocomposites

Abstract

The reinforcing effects of carbon nanotubes (CNTs) are investigated for aluminum matrix composites. The composites present a strong bonding between CNTs and the aluminum matrix using a controlled mechanical milling process, producing a network structure of aluminum atoms around CNTs. At the same time, CNTs that are dispersed during the milling process can be located inside aluminum powders, thereby providing an easy consolidation route via thermomechanical processes. A composite containing 4.5 vol% multiwalled CNTs exhibits a yield strength of 620 MPa and fracture toughness of 61 MPa·mm1/2, the values of which are nearly 15 and seven times higher than those of the corresponding starting aluminum, respectively.

Deformation and strengthening mechanisms of a carbon nanotube reinforced aluminum composite

“…The enhancement of flow curves in the composite compared with the base alloy was also observed at all test temperatures at a fixed strain rate ( Fig.8(b)), indicating the importance of CNT reinforcement in the improvement of the mechanical properties. Similarly, Choi et al [54] also observed the improvement in the flow resistance by the addition of CNTs while studying composites with different volume fractions of MWCNTs (i.e., 1.5, 3, 4.5 and 6 vol.%) at different temperatures. The evaluated CYS and UCS are shown in Fig.10.…”

An approach for homogeneous carbon nanotube dispersion in Al matrix composites

“…Flaky Al particles with greatly improved surface areas have been reported in high-energy ball milling (HEBM) processes by preventing cold-welding of Al powders [10,16]. However, due to the ignorance of the strong attractive force between CNTs HEBM process also confronted the severe CNT damages for dispersing CNTs [17]. Accordingly, homogeneous CNT dispersion with minor or small structure change in composites is difficult to obtain from the conventional methods based on a single-aspect strategy.…”

Synthesis of nanodiamond-reinforced aluminum metal composite powders and coatings using high-energy ball milling and cold spray

“…While few materials in their elemental form can meet these requirements, the development of nanostructure-reinforced metal matrix composites (MMCs) has opened new pathways for the design of new materials that exhibit a unique set of properties, such as high strength and low weight. The performance of MMCs depends primarily on the ability (1) to adequately disperse the reinforcement agents in the metal matrix, (2) to maintain its structural integrity during composite synthesis and processing, and (3) to establish a 0008-6223/$ -see front matter Published by Elsevier Ltd. http://dx.doi.org/10.1016/j.carbon.2013.07.001 suitable matrix-reinforcement agent interface [1][2][3][4][5][6]. The strength of a MMC can be further enhanced by reducing the crystal size of the metal matrix to the lower nanoscale [7].…”