Abstract
This paper focuses on reporting results obtained by the spark plasma sintering (SPS) consolidation and characterization of aluminum-based nanocomposites reinforced with concentrations of 0.5 wt%, 1 wt% and 2 wt% of single-walled carbon nanotubes (SWCNTs) and multi-walled carbon nanotubes (MWCNTs). Experimental characterization performed by SEM shows uniform carbon nanotube (CNT) dispersion as well as carbon clusters located in the grain boundary of the Al matrix. The structural analysis and crystallite size calculation were performed by X-ray diffraction tests, detecting the characteristic CNT diffraction peak only for the composites reinforced with MWCNTs. Furthermore, a considerable increment in the crystallite size value for those Al samples reinforced and sintered with 1 wt% of CNTs was observed. Hardness tests show an improvement in the composite surface hardness of about 11% and 18% for those samples reinforced with 2 wt% of SWNCTs and MWCNTs, respectively. Conductivity measurements show that the Al samples reinforced with 2 wt% of MWCNTs and with 0.5 wt% SWCNTs reach the highest IACS values of 50% and 34%, respectively.
Highlights
The secondary electrons (SE)-Scanning Electron Microscopy (SEM) micrographs in Figure 1a–c show the presence of single-walled carbon nanotubes (SWCNTs) entangled together, especially in samples S2 and S3
The results obtained in this article show that Al-based nanocomposites reinforced with unmodified carbon nanotube (CNT) and sintered via spark plasma sintering (SPS) are excellent candidates to manufacture materials with enhanced electrical conductivity and mechanical properties
Despite the high-energy ball-milling process, the SWCNTs were not able to be dispersed satisfactorily due to the strong Van der Waals interaction resulting in the creation of large clusters and, hindering their properties
Summary
The investigation of metal matrix composites (MMCs) in recent decades has been key to improve the mechanical, electrical and thermal performances in developed composites materials with the main objective of being implemented in the industry [1,2]. Aluminum-based (Al-based) nanocomposites materials have been extensively investigated due to their excellent mechanical and physical properties such as good formability, high corrosion resistance, lightweight and low melting temperature which makes them an ideal candidate for application in aerospace and automobile industries [2]. Al-based CNT nanocomposites [3,4,5,6] due to their exceptional electrical, mechanical and thermal properties [7,8,9]. The uniform dispersion and optimal bonding of CNTs in the Al matrix have been identified as being critical to enhance its physical properties since the formation of interfacial phases between both Al and CNTs can influence mechanical, electrical and thermal properties of the Al-based CNT composite [11]
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