Influence of sintering methods on the mechanical properties of aluminium nanocomposites reinforced with carbonaceous compounds: A review (original) (raw)
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Journal of Advances in Physics, 2018
The present work is concerned with studying the synthesis and characterization of hybrid aluminum bronze matrix strengthened with nano-aluminum oxide particles (n-Al2O3), and carbon nano tubes (CNTs). The selected matrix composite was successfully incorporated with different weighted percentages of CNTs (i.e. 1.0 and 2.0 wt.%) and/or n-Al2O3 (i.e. 1.0 and 2.0 wt.%) by sintering process. From the microstructure analysis, n- Al2O3 particles was dispersed uniformly and holding over the surface of aluminum bronze. Furthermore, some agglomeration was found due to reinforced CNTs into aluminum bronze matrix. From hardness tests, it was found that incorporated n- Al2O3 and CNTs into matrix increased the hardness of composites to be equal 230 HV, which is around 2.3 times higher than that of an aluminum bronze matrix. Moreover, the wear loss of CNTs - Al2O3/aluminum bronze composites diminished because of the impact of homogeneous circulation of CNTs in aluminum bronze and low corrosion coe...
Acta Physica Polonica A, 2017
In this study, the effects of sintering time on hardness and wear behaviour were investigated of carbon nanotubes reinforced aluminium matrix composites. 1% multi wall carbon nanotubes (90% purity with 9.5 nm in diameter, 1.5 µm in length) and gas atomized 7075 Al alloy powders were mechanical milled for 120 min in a planetary ball mill. Mechanical milled aluminium composite powders were cold pressed under 520 MPa. Pre-shaped samples were sintered in atmosphere controlled furnace at 580 • C for three different sintering times (1, 2, and 3 h). As a result of study, it was observed that the hardness values of composites were decreased with increasing sintering time and the weight loss was decreased. It was determined from worn surface SEM images that adhesive wear mechanisms were dominant.
Article, 2023
In this research, the effects of heat treatment and hybrid reinforcement ratio on the microstructural and mechanical properties of Al-4Cu nanocomposites containing MWCNT and nano Al 2 O 3p were investigated. First of all, the hybrid reinforced Al-4Cu nanocomposites were manufactured with the aid of mechanical alloying and microwave sintering. And then, they were subjected to various heat treatments; annealing and artificial aging at 170, 180 and 200 °C individually. After that, the microstructural observations were made using X-ray diffraction, optical microscope and scanning electron microscopes (SEMs). The secondary electrons (SE), back scattered electrons (BSE), energy dispersive X-ray (EDX) and elemental mapping analyses of the specimens were carried out with the aid of SEMs. In addition, the nanoindentation tests were done to get the nanohardness and elastic modulus of composites. Finally, the composites were subjected to the compression test to clarify their compressive properties. The Al 2 Cu and Al 4 C 3 precipitates were detected in the composite samples either annealed or peak-aged at 200 °C, while the intermetallic compound, Al 7 Cu 2 Fe, precipitated only in the aged samples. A significant increment in the nanohardness of composites was obtained with increasing reinforcement content. Moreover, the elastic modulus of annealed and peak-aged composites, reinforced with 15% hybrid reinforcement in volume, increased by 59% and 57%, respectively compared to the unreinforced alloy. Furthermore, the use of hybrid reinforcement in the alloy matrix allowed an improvement of compressive yield strength at the expense of compressive strain.
Materials Research, 2016
The present work deals with the study of some aluminum (Al) composites reinforced with metallized-graphite (MG) particles prepared by mechanical milling and powder metallurgy routes. Density, morphology evolution and mechanical performance of composites were investigated as a function of MG concentration and milling time. The as-milled powders were characterized by X-ray diffraction and optical/electron microscopy; meanwhile, the mechanical testing was carried out on cylindrical specimens prepared from powders by powder metallurgy. Evidence reveals that high-energy ball milling induce a homogeneous dispersion of graphite nanoparticles in the Al matrix; this is related to an enhancement of hardness and strength response of studied composites. The composite sample with 0.5% MG addition (in weight) reached an increase of 40% on hardness and 50% on strength (compared with pure Al sample); nevertheless an adverse effect was observed with longer milling and/or higher MG concentration.
Carbon nanotubes-reinforced aluminium with improved yield strength and toughness
Among carbon nanotubes (CNTs) based composites, aluminium/CNTs ones are rather promising for weight sensitive applications, such as in aerospace field, thanks to the combination of the low weight and high stiffness and strength of the reinforcement. In this work, a self-assembled apparatus, named Pressure Assisted Fast Electric Sintering (PAFES), has been employed for the sintering of commercial micrometre size aluminium powders with multi-wall carbon nanotubes (MWCNTs). To do this effectively, much effort was devoted to the fundamental step of the CNTs dispersion and mixing in the Al powders by high energy milling.
Journal of Solid Mechanics and Materials Engineering, 2010
Carbon nanotube is nature's smallest fiber and predicted to have a range of unusual mechanical and electrical properties. One possible route to harnessing these properties for applications would be to incorporate nanotubes in a composite material. Here, we report the mechanical properties of multi-walled carbon nanotube (MWCNT) reinforced alumina composites made with a pristine MWCNT and an acid-treated version that have nanoscale defects on their surfaces from an acid treatment. It was demonstrated that surface modification of the MWCNT is effective in improvement of bending strength and fracture toughness of the MWCNT-reinforced alumina composites. On the basis of the results, we also prepared three sets of the acid-treated MWCNT-reinforced alumina composites having different sintering additives, in order to investigate the effects of sintering additives on their microstructures and mechanical properties. Mechanical properties of the composites were dependent mostly on the type of sintering additives and amount of MWCNT. The 0.9 vol.% acid-treated MWCNT-reinforced alumina composites with MgO sintering additive gave the highest bending strength (689.6 ± 29.1 MPa) and fracture toughness (5.90 ± 0.27 MPa•m 1/2), respectively.
Journal of materials science and engineering, 2015
The nanocomposite based on carbon nanotubes/aluminum (CNT/Al) was one-step prepared by the DC arc discharge method under an argon/acetone mixed atmosphere. Synthesis was performed by arc plasma on a pure graphite rod, filled by aluminum powder as an anode and aluminum plate as a cathode. Discharge conditions of 85 A and 20 V were used at a pressure range of 375 to 750 Torr. The CNT/Al was characterized by Scanning Electron Microscopy with Energy Dispersive Spectroscopy; Transmission Electron Microscopy; Laser Diffraction Particle Size Analysis; X-Ray Diffraction; Raman Spectroscopy; Thermogravimetric Analysis; and, its reinforcement effect of the CNTs on the aluminum matrix was measured by Vickers microhardness test. This nanocomposite shows agglomerates of multiwalled carbon nanotubes filled with Al 4 C 3 and blended with aluminum particles; moreover, in the nanocomposites was found a hardness increase of 40% for nanocomposites with 1.0 wt.% of CNT/Al.
AN OVERVIEW ON THE MICROSTRUCTURE AND MECHANICAL PROPERTIES OF SINTERED ALUMINUM-BASED COMPOSITES
Sintered composites have revolutionized as a thermal treatment to consolidate a wide range of engineering materials where the transition of powders takes place thermally in a thermodynamical equilibrium state with a decrease in free surface energy in materials owing to their specific capability. Sintering aids in providing effective bonding between the reinforced powder particles. However, the inadequate understanding of the sintering mechanism may limit the practical application of a few materials such as aluminum metal matrix composites. In addition to the rapid growth of various sintering related technologies, researchers need attention to highlight the structural barriers and forecast the emerging demands while dealing with such composites. A review report is made in this paper regarding the sintering mechanisms and sintering techniques. Common sintering techniques such as traditional, microwave assisted, hot pressing, hot isostatic sintering, and spark plasma sintering are identified and discussed here. As a result, the key challenges in sintering aluminium metal matrix composites that can affect sintering parameters are investigated. From the review, spark plasma is identified to attain densified and pore-free green composites and, microwave sintering is the best technique for achieving uniform microstructure in powder metallurgy samples.
Aluminum alloys and aluminium based composites are used presently in engineering applications. Aluminium matrix composites are imparting such superior properties which are very difficult to achieve by any existing monolithic material. These composites (MMCs) pursued over other conventional materials in the field of aerospace, automotive and marine applications due to their outstanding improved properties. These materials are of much interest to the researchers from few decades. These composites primarily replaced ferrous based such as cast iron and alloyed high temperature nonferrous based materials such as brass or bronze alloys but because of their poor wear and seizure resistance, they were subjected to many experiments and the wear behavior of these composites were explored to a maximum extent and were reported by number of research scholars for the past couple of years. Properties of aluminum matrix composites are highly influenced by the type and geometry of reinforcement such as particle size, continues or discontinues fiber form. It also depends on the processing techniques adopted for the fabrication of aluminum matrix composites which also depends on many factors including type of matrix and reinforcement the extent of microstructural integrity desired and their structural, mechanical and thermal properties. Present paper reports an overview on synthesis routes or processing methods as solid or liquid state techniques used to produce specimens with different reinforcements including carbon nanotubes. Mechanical and tribological behavior and its challenges of aluminum matrix composites are discussed. © 2020, IRJET | Impact Factor value: 7.529 | ISO 9001:2008 Certified Journal | Page 430