Fabrication and mechanical properties of CNT/Al composites via shift-speed ball milling and hot-rolling
14 Aug 2019-Journal of Materials Research (Springer International Publishing)-Vol. 34, Iss: 15, pp 2609-2619
TL;DR: In this paper, carbon nanotubes (CNTs) reinforced Al matrix composites were fabricated using flake powder metallurgy via shift-speed ball milling and hot-rolling.
Abstract: Flat products of carbon nanotubes (CNTs) reinforced Al matrix composites were fabricated using flake powder metallurgy via shift-speed ball milling and hot-rolling. The evolution of CNTs during preparation and the final distribution in the Al matrix were investigated, and the effect of CNT content on mechanical properties were discussed. Due to the combined effect of uniform dispersion of CNTs, structural integrity, interfacial bonding and directional alignment, the balance between high strength and ductility was successfully achieved in the annealed rolled composites with 1.5 wt% CNT addition, with the value of 382.6 MPa in tensile strength and 9.8% in fracture ductility. The load transfer strengthening was the main mechanism of the strength enhancement with CNTs addition. In addition, a strong rotated cube {001}〈110〉 texture was found in the final flat product of rolled composites. This study provides an effective route to produce and improve the mechanical properties of CNT/Al flat products.
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TL;DR: A review of the tensile properties of carbon nanotube reinforced aluminium matrix (Al-CNT) composites can be found in this article, where various processing routes for fabrication of AlCNT composites have been compared in terms of the resulting microstructure, degree of CNT dispersion, extent of interfacial reaction and its effect on the tensil properties.
118 citations
TL;DR: In this paper, an easy strategy was proposed to avoid and eliminate the negative effect of native oxide (Al2O3) layer by Mg addition, and significant improvement of ductility was achieved in the CNT/Al-Cu composite.
Abstract: The inevitable native oxide layer is a critical issue to achieve high mechanical performance of CNT/Al-alloy composites, especially prepared by powder metallurgy. Here, an easy strategy was proposed to avoid and eliminate the negative effect of native oxide (Al2O3) layer by Mg addition, and significant improvement of ductility was achieved in the CNT/Al-Cu composite. Native Al2O3 remained as continuous layers around CNTs or clusters of fragments in the CNT/Al-Cu without Mg addition. Mg addition transformed the native Al2O3 layer into spinel MgAl2O4 nano-phases dispersed both inside grains and on the interfaces. It is supposed that this transformation of oxide layer could improve the interfacial bonding due to Al-Al and Al-CNT direct interfacial contact. As a result, compared with CNT/Al-Cu composites, the tensile strength only changed a little, however, almost two times of fracture ductility was achieved by Mg addition in the final composites.
17 citations
TL;DR: In this paper, the effect of aging treatment on mechanical properties of CNT/Al-Cu-Mg composites was investigated, and the aging effect was observed in the composites compared with matrix alloy.
Abstract: Influence of aging treatment on mechanical properties was investigated in the CNT/Al–Cu–Mg rolled composites. The tensile strength of composites was strongly dependent on the aging annealing treatment, and stronger aging effect was observed in the composites compared with matrix alloy. The ultimate tensile strength was highest in the CNT/Al–Cu–Mg composites with peak-aging treatment, however, it sharply decreased when samples were over-aged. In addition to the load transfer and grain refinement, CNTs addition introduced strong back stress, and the aging nanoprecipitation strengthening promoted the strain hardening capability, which both significantly improved the ultimate tensile strength of composites.
7 citations
08 Jun 2021
TL;DR: A review of the main results of research on FPM can be found in this paper, which indicates the potential for future studies devoted to the optimization of this processing route and indicates that future studies are devoted to FPM optimization.
Abstract: This paper reviewed several recent progresses of the new powder metallurgy technology known as flake powder metallurgy (FPM) including different processing routes, conventional FPM (C-FPM), slurry blending (SB), shift-speed ball milling (SSBM), and high-shear pre-dispersion and SSBM (HSPD/SSBM). The name of FPM was derived from the use of flake metal powders obtained by low-speed ball milling (LSBM) from spherical powder. In this case, the uniformity of reinforcement distribution leads to increased strength and ductility. Powder is the basic unit in PM, especially advanced PM, and its control is key to various new PM technologies. The FPM is a typical method for finely controlling the powder shape through low-energy ball milling (LEBM) to realize the preparation of advanced material structures. The present paper represents a review of the main results of research on FPM and indicates the potential for future studies devoted to the optimization of this processing route.
7 citations
TL;DR: In this article , the mechanical properties of Al are enhanced by reinforcing with bimodal micron-sized Niobium carbide (NbC) and nano-sized Boron Carbide (B4C) ceramic particles.
Abstract: Aluminum (Al) is an earth-abundant metal recognized with superior properties for vital applications in the aerospace and transportation industries. Structural components of Al exhibit poor performance due to its inherent low mechanical strength. In this work, the mechanical properties of Al are enhanced by reinforcing with bimodal micron-sized Niobium Carbide (NbC) and nano-sized Boron Carbide (B4C) ceramic particles. Al-NbC-B4C hybrid composites have been synthesized via ball milling followed by cold compaction and microwave sintering. NbC micro-reinforcement composition has been kept fixed (5 wt%), while B4C nano-reinforcement composition varied from 0.5 wt%, 1.0 wt%, 1.5 wt%, and 2.0 wt%. XRD patterns revealed the high crystallinity with no detected new phases formed in the sintered composites. TEM micrographs presented the microstructure evolutions with uniform distribution of (micron + nano) hybrid bimodal-sized ceramic reinforcements in the Al matrix. FE-SEM micrographs and corresponding elemental mapping demonstrated the homogeneity in the elemental distribution of synthesized Al-NbC-B4C composites through the ball milling and microwave sintering processes. Roughness values and AFM images showed the formation of insoluble secondary phases dispersed in the Al matrix enhancing its surface resistance towards localized plastic deformations. Al-5 wt%NbC-2.0 wt%B4C composite has exhibited an ultrahigh improvement in the mechanical properties compared to pure Al. It showed enhancements in microhardness (46%), nanohardness (54%), and Young’s modulus (31%). It also showed high ultimate compression strength of 328 MPa and a low engineering failure strain of 0.64. FE-SEM compressive fractography confirmed the strengthened dispersion hardening effect from bimodal-sized ceramic particles obstacle multi-length cracks and resisting fracture failure.
4 citations
References
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TL;DR: In this article, the authors focus on the recent development in the synthesis, property characterization and application of aluminum, magnesium, and transition metal-based composites reinforced with carbon nanotubes and graphene nanosheets.
Abstract: One-dimensional carbon nanotubes and two-dimensional graphene nanosheets with unique electrical, mechanical and thermal properties are attractive reinforcements for fabricating light weight, high strength and high performance metal-matrix composites. Rapid advances of nanotechnology in recent years enable the development of advanced metal matrix nanocomposites for structural engineering and functional device applications. This review focuses on the recent development in the synthesis, property characterization and application of aluminum, magnesium, and transition metal-based composites reinforced with carbon nanotubes and graphene nanosheets. These include processing strategies of carbonaceous nanomaterials and their composites, mechanical and tribological responses, corrosion, electrical and thermal properties as well as hydrogen storage and electrocatalytic behaviors. The effects of nanomaterial dispersion in the metal matrix and the formation of interfacial precipitates on these properties are also addressed. Particular attention is paid to the fundamentals and the structure–property relationships of such novel nanocomposites.
877 citations
TL;DR: In this paper, an aluminum and carbon nanotube (CNT) composites with nanoscale dispersion and regular orientation of the CNTs were fabricated by a combination of some advanced powder processes.
552 citations
TL;DR: In this article, the effect of milling time (up to 48 hours) on the morphological development of the powders and dispersion of CNTs was investigated, and the results show that the technique is effective in dispersing the nanotubes within the soft Al matrix.
Abstract: In the present work, we use mechanical alloying (MA) for the first time to generate a homogenous distribution of 2 wt% CNT within Al powders. The effect of milling time (up to 48 h) on the morphological development of the powders and dispersion of CNTs was investigated. The results show that the technique is effective in dispersing the nanotubes within the soft Al matrix which simultaneously protects the nanotubes from damage under the impact of the milling balls. The results can have important implications for the processing of CNT-reinforced metal-matrix composites in general.
400 citations