Aluminum Matrix Nanocomposites Research Articles

Evaluation of mechanical and tribological properties of Aluminium metal matrix composite reinforced with titanium diboride and graphite

The purpose of this research is to assess mechanical and tribological behavior of Aluminum matrix nanocomposites reinforced with varying weight percentage of 0%, 2.5%, 5%, 7.5%, 10% and 12.5% titanium diboride (TiB2) nano particles and 6% graphite (Gr) nanoparticles through electromagnetic stir casting process. Microstructure analysis were examined using Optical microstructure, Scanning Electron Microstructure, Energy Dispersive Spectrum and phases of reinforced particles in the Aluminium alloy were identified using X-ray diffraction. Mechanical and tribological testing were conducted. Regarding mechanical properties such as tensile strength, flexural strength, compression strength, and wear resistance of all reinforced composite specimens presented enhanced properties than the unreinforced matrix. It was found that the enhanced mechanical properties and wear behavior of the tested specimens of aluminium hybrid nanocomposites has been achieved due to presence of strengthening of hard ceramic nanoparticles of TiB2 in the matrix.

Corrosion behavior of Al/TiO2/Y2O3 hybrid nanocomposites manufactured using the vacuum-assisted stir casting route

PurposeThis study aims to examine the corrosion and flexural behaviour of advanced hybrid aluminium matrix nanocomposites (HAMNCs) made with a vacuum-assisted stir die casting (two-layer feeding) and reinforced with titanium oxide (TiO2) and yttrium oxide (Y2O3) nanoparticles. The previous researchers have shown that TiO2 and Y2O3 nanoparticles make aluminium composites much more resistant to corrosion and wear.Design/methodology/approachSalt spray corrosion tests were done on the samples over time as well as the pre-and post-corrosion morphology of the test samples was also investigated. The density, porosity and energy dispersive X-ray of the fabricated samples were observed.FindingsIt was observed that a lower corrosion rate of 0.127 mils/year and 0.573 mils/year was seen in the Al/5 Wt.%TiO2/5 Wt.%Y2O3 (HAMNC1) and Al/7.5 Wt.%TiO2/2.5 Wt.%Y2O3 (HAMNC3), respectively. It was evident from the results that the pores and densities of the samples varied with the filler concentrations and matrix filler wettability. HAMNC1 has the lowest values of density and porosity at 2.568 g/cm3 and 9.91%, respectively. At the same time, a significant improvement in the flexural strength of 72 N/mm2 was also seen in the HAMNC1 configuration.Practical implicationsThe proposed hybrid samples are well suited for aerospace and automobile structural components such as brake drums, discs, engine cylinders and fins.Originality/valueThe mixed influence evaluation of TiO2 and Y2O3 nanoparticles with pure Al on composite samples has not been studied. This research aims to examine the combined influence of nanoparticles on the corrosion aspects of two-step feeding vacuum stir casted products, as well as their morphology.

Enhanced microstructure and mechanical properties of Al6061 alloy via graphene nanoplates reinforcement fabricated by stir casting

In this research, graphene/Al6061 aluminum matrix nanocomposites were fabricated by stir casting, and the influence of graphene nanoplates on microstructure and mechanical properties of the 6061 aluminum alloy were investigated by field emission scanning electron microscopy (FESEM), energy dispersive spectroscopy, tensile and hardness testing analysis methods. The major limitation in the utilization of 6061 aluminum alloy in heavy stress applications such as airplane fuselages, wings, internal panels, and luxury vehicles chassis is low strength and hardness. This deficiency of 6061 aluminum alloy was tackled by successful reinforcement of graphene nanoplates in 2, 4, 6, 8 and 10 wt.%, using the stir casting process. The FESEM micrographs showed that the graphene nanoplates were uniformly distributed in the 6061-aluminum matrix alloy and tensile strength, hardness, and yield strength enhanced remarkably as compared with unreinforced 6061 aluminum alloy. The as-cast tensile strength, hardness, and yield strength of the graphene/Al6061 nanocomposites were improved by 127%, 158%, and 402%, respectively, compared with the unreinforced Al6061 alloy. It is concluded that the nano thickness of graphene, reinforcement quantity, and manufacturing process are the major factors for the enhancement of microstructure and mechanical properties of graphene/Al6061 nanocomposites.

Effect of Al2O3 Nanoparticles as Reinforcement on the Wear Properties of A356/Al2O3 Nanocomposites Produced by Powder Metallurgy

Abstract In this study, microstructure and wear properties of A356 aluminum matrix nanocomposites reinforced with nano-Al2O3 particles were investigated. The powder metallurgy method was used for the production of 1 wt% and 2 wt% nano-Al2O3 particle reinforced nanocomposites. After 1 h of mechanical milling of A356 and nano-Al2O3 powders, green compacts were obtained by cold pressing. Green compacts were sintered at 550 °C in a vacuum environment (10−6 mbar) for 1 h. Samples were characterized by density, hardness measurements, scanning electron microscopy investigations, and wear tests. As the reinforcement ratio increased, there was a decrease in the densities of the nanocomposites, as well as an increase in the porosity. The highest hardness and the lowest weight loss values were obtained in 1 wt% Al2O3 reinforced nanocomposites. A decrease in hardness was measured at 2 wt% Al2O3 reinforced nanocomposites.

Liquid Processing of Bismuth–Silica Nanoparticle/Aluminum Matrix Nanocomposites for Heat Storage Applications

Metal matrix nanocomposites encompassing low-melting point metal nano-inclusions are promising candidates for thermal regulation of devices at high temperature. They are usually processed by solid-state routes that provide access to a limited range of materials and are hardly compatible with complex shaping processes and with large-scale applications. Herein, we develop a liquid-phase processing technique to design aluminum matrix nanocomposites made of phase change nanoparticles, using bismuth nanoparticles as a proof-of-concept. The bismuth nanoparticles derived from colloidal chemistry are first encapsulated in a silica shell and then dispersed by ultrasonication into molten aluminum. Using X-ray diffraction, electron microscopy, and X-ray photoelectron spectroscopy, we probe the evolution of the bismuth particles and of the inorganic shell. We demonstrate that the silica shell acts as a barrier against extensive coalescence of particles during the dispersion process, thus enabling a decrease and a widening of the phase change temperature range.

Ultrasonic effects on gas tungsten arc based wire additive manufacturing of aluminum matrix nanocomposite

This study focused on a newly developed ultrasonically assisted (UA) wire arc additive manufacturing (WAAM) process for metal matrix nanocomposite of AA7075 with TiB2 nanoparticles. The ultrasonic probe was directly dipped into the local molten pool and traveled behind the arc during deposition. Comprehensive experimental studies were performed and the UA-WAAM sample showed superiorities over conventional WAAM ones in multiple perspectives including a lower number of porosities, refined solidification structure, and less agglomerated nanoparticle distribution under the same deposition parameters. These improved microstructure features led to enhanced mechanical properties of the UA-WAAM samples, as reflected in the tensile tests and hardness measurement results. The benefits of nanoparticles in the formation of equiaxed grain structures and strength contribution was further leveraged by UA based on their better dispersion. The ultrasonic effects on WAAM process can be mainly attributed to the two nonlinear physical phenomena: acoustic cavitation and streaming induced by power ultrasound in molten metal.

Mechanical properties of Al6005A-nTiC nano-composite obtained by milling, hot extrusion and FSW

An aluminium matrix nano-composite (AlMNC) was obtained by a powder metallurgy (P/M) process, consisting of an ex situ reinforcement of pre-alloyed AA6005A powders with 3% vol. of TiC nanoparticles (nTiC), high-energy mechanical milling (HEMM) and hot extrusion powder (HEP). AA6005A powder was chosen as matrix because it is a heat-treatable medium strength Al alloy with excellent corrosion resistance, extrusion performance and good weldability; and the nTiC particles due to their low density, good chemical stability and excellent combination of hardness and elastic modulus. HEMM allowed obtaining an ultra-fine grained (UFG) matrix, a uniform dispersion of the nano-reinforcement and its proper incorporation in the ductile matrix. Simultaneously, the repeated plastic deformation of matrix powder led to a high density of crystal defects, and the large number of dislocation barriers produced by nTiC particles are responsible of the obtained nanostructured composites. HEP allowed obtaining high quality extrudates with an a homogeneous distribution of nanoparticles. The hardness of the nanocomposite is almost 43 % higher than that of the unreinforced AA6005A, showing important increases in yield strength and ultimate tensile strength with a 5% elongation. The extruded profiles were Friction Stir Welded (FSW) obtaining sound welds. The grain size refinement on the stir zone (SZ), led to a slight increase in hardness in the welds.

Investigation on wear behavior of aluminium matrix micro and nanocomposites

Aluminum matrix composites (AMCs) have a wide range of applications in aerospace, marine, and automobile because of their improved tribological and mechanical properties. In the present article, Al7075 alloy was used as the matrix material filled with micro (average size 50 μm) and nano (average size 80 nm) particles of Al2O3 (alumina). The same quantity of weight fractions of micro and nano alumina particles were injected into the semi-solid state of Al7075 aluminum alloy by the mechanical stir casting process. The developed composites have been investigated for specific wear rate (SWR) by using Pin on Disc Tribometer. The results of nano and micro composites have been compared at similar combinations of input parameters. The normal load, sliding distance, and sliding velocity were the input parameter for analyzing the SWR. The result shows that SWR increased with an increase in normal load and sliding distance. It has been found from the results that SWR is inversely proportional to sliding velocity. Also, results indicate that SWR of the developed AMCs containing nano alumina was found superior to that of the micro composite and base material.

Strengthening Mechanisms of Aluminum Matrix Nanocomposites Reinforced with CNTs Produced by Powder Metallurgy

The present work aims to investigate the strengthening mechanisms in aluminum matrix nanocomposites reinforced by carbon nanotubes (CNTs). A classical powder metallurgy route produced Al-CNT nanocomposites using ultrasonication and ball milling as dispersion/mixture techniques. The microstructural characterization is crucial for this study to reach the objective, being performed mainly by electron backscattered diffraction (EBSD), transmission electron microscopy (TEM), and high-resolution TEM (HRTEM). Uniform dispersion without damaging the CNTs structure is the key for the nanocomposite by powder metallurgy production process. The reinforcement effect occurs due to several strengthening mechanisms that act simultaneously. For the Al-CNT nanocomposites produced by ultrasonication as a dispersion/mixture technique, the observed improvement in the mechanical properties of nanocomposites can be attributed to the load transfer from the matrix to the CNTs. The strain hardening and the second-phase hardening can also have a small contribution to the strengthening of the nanocomposites.

Machine-learning-assisted microstructure–property linkages of carbon nanotube-reinforced aluminum matrix nanocomposites produced by laser powder bed fusion

Abstract In this study, the cellular microstructural features in a subgrain size of carbon nanotube (CNT)-reinforced aluminum matrix nanocomposites produced by laser powder bed fusion (LPBF) (a size range between 0.5–1 μm) were quantitatively extracted and calculated from scanning electron microscopy images by applying a cell segmentation method and various image analysis techniques. Over 80 geometric features for each cellular cell were extracted and statistically analyzed using machine learning techniques to explore the structure–property linkages of carbon nanotube reinforced AlSi10Mg nanocomposites. Predictive models for hardness and relative mass density were established using these subgrain cellular microstructural features. Data dimension reduction using principal component analysis was conducted to reduce the feature number to 3. The results showed that even AlSi10Mg nanocomposite specimens produced using different laser parameters exhibited similar Al–Si eutectic microstructures, displaying a large difference in their mechanical properties including hardness and relative mass density due to cellular structure variance. For hardness prediction, the Extra Tress regression models showed a relative error of 2.47% for prediction accuracies. For the relative mass density prediction, the Decision Tress regression models showed a relative error of 1.42% for prediction accuracies. The results demonstrate that the developed models deliver satisfactory performance for hardness and relative mass density prediction of AlSi10Mg nanocomposites. The framework established in this study can be applied to the LPBF process optimization and mechanical properties manipulation of AlSi10Mg-based alloys and other additive manufacturing newly designed alloys or composites.

Evolution of Microstructure, Texture and Mechanical Properties for Multilayered Al Matrix Composites by Accumulative Roll Bonding.

Carbon nanotubes (CNTs) reinforced aluminum matrix nanocomposites were fabricated by Accumulative Roll Bonding (ARB). The surface morphologies, mechanical properties, grains texture and orientation of the Al/CNTs nanocomposites were characterized, and the mechanisms and influences of CNTs contents and ARB cycles on the mechanical performance and grain textures of Al/CNTs were investigated and revealed. The strength of the composites rose with increase of the CNTs content, and the ARB cycles showed a 26% improvement when the CNTs content varied from 0 to 1 volume percent (vol.%). The increase in the mass fraction of the carbon nanotubes made the grain distribution in the Al/CNTs nanocomposite samples more diffuse. Besides, the stable texture of the hot rolled crystal grains on the α orientation are constantly turning to {011}< 011> with the mass fraction of the reinforcing phase increased.

In-situ synthesis of aluminum matrix nanocomposites by selective laser melting of carbon nanotubes modified Al-Mg-Sc-Zr alloys

Aluminum matrix nanocomposites were manufactured by selective laser melting (SLM) of 0.5 wt% multi-walled carbon nanotubes (MWCNTs) modified Al-Mg-Sc-Zr alloys. The influence of MWCNT addition on the manufacturing quality, the phase formation and the mechanical properties of the Al-Mg-Sc-Zr alloys was investigated. It is found that primary Al3(Sc,Zr) particles precipitated and were uniformly dispersed in both equiaxed and columnar regions of the SLM-fabricated MWCNTs/Al-Mg-Sc-Zr nanocomposites. New Al4C3 phase was generated either on the open tip or in the defected and amorphous carbon layer of the MWCNTs, covering their overall surface. The unreacted MWCNTs completely transferred to Al4C3 upon heat treatment, forming a stable {003} Al4C3/{200}Al interface. The heat-treated MWCNTs/Al-Mg-Sc-Zr nanocomposites exhibit high microhardness of 169.0 ± 0.7 HV0.2, tensile strength of 544.2 ± 6.8 MPa, yield strength of 505.1 ± 6.3 MPa and elastic modulus of 97.8 ± 0.7 GPa, increasing by 6.3%, 4.5%, 5.0% and 5.6%, respectively, compared with the unmodified Al-Mg-Sc-Zr alloys. The improved performance was ascribed to the collective effects of precipitation strengthening of secondary Al3(Sc,Zr) nanoparticles, in-situ synthesis of Al4C3 as well as favorable interfacial bonding for effective load transfer. This study can provide reference values for laser additive manufacturing of MWCNTs modified other metallic alloys to enhance their comprehensive properties.

In situ synthesized nano-Al4C3 reinforced aluminum matrix composites via friction stir processing

The strength-ductility trade-off problem of carbon nanotube (CNT) reinforced aluminum matrix nanocomposites (AMNCs) restricts its further application. Hence, we report the fabrication of nano-Al 4 C 3 reinforced AMNCs through friction stir processing (FSP) on CNT/Al composites which can simultaneously elevate the ductility of the composite and maintain the original strength. The microstructure evolution and the dispersion of reinforcement are investigated. Tensile tests show that the elongation of the Al 4 C 3 /Al composites fabricated via FSP at a rotation rate of 800 rpm increased by 1.6 times than that of CNT/Al composite and the yield strength retained 95%. The improvement of the mechanical properties is due to the strong Al 4 C 3 –Al interface, homogeneous dispersion, nano size, and dynamic recrystallization during FSP. Grain refinement and Orowan strengthening are the main strengthening mechanisms of Al 4 C 3 /Al composites. This research shares an approach to preparing a nano-Al 4 C 3 reinforced aluminum matrix composite with well strength and outstanding ductility.

Strengthening Mechanisms of 15 vol.% Al2O3 Nanoparticles Reinforced Aluminum Matrix Nanocomposite Fabricated by High Energy Ball Milling and Vacuum Hot Pressing

Strengthening Mechanisms of 15 vol.% Al2O3 Nanoparticles Reinforced Aluminum Matrix Nanocomposite Fabricated by High Energy Ball Milling and Vacuum Hot Pressing

Effect of SiC and MoS2 Co-reinforcement on Enhancing the Tribological and Anti-Corrosive Performance of Aluminum Matrix (Al6063-T6) Nanocomposites

Effect of SiC and MoS2 Co-reinforcement on Enhancing the Tribological and Anti-Corrosive Performance of Aluminum Matrix (Al6063-T6) Nanocomposites

Evaluation the microstructure, physical, magnetic and electrical properties of Al/Fe3O4 + Ni hybrid nanocomposite

This paper aims to study the physical, electrical, magnetic properties and microstructural analysis of aluminum matrix incorporated with different amounts of Fe3O4 at (2,4,6,8 and 10wt.%) with a constant amount of Ni at 2wt.%. Al/Fe3O4 +Ni hybrid nanocomposites specimens were prepared using the powder metallurgy method. Aluminum matrix nanocomposites (AMNCs) are important alloys because of their high strength, wear resistance, and lightweight, which enables them to be used in different thermal environments in a variety of applications including automotive, electronics, and aerospace. Many examinations, including Field Emission Scanning Electron Microscopy (FESEM)) analysis, were performed on the specimens in this study to determine the microstructure and phases of the nanocomposites, and study important properties such as density, porosity, magnetic and electrical properties, to evaluate these properties of the hybrid nanocomposites. FESEM analysis revealed that Fe3O4 and Ni nanoparticles were homogeneously distributed in the Al matrix in this study. The results of these tests showed that increasing the weight percentage of Fe3O4 and constant weight percentage of Ni nanoparticles decreases the porosity and increases the density and increases saturation magnetization (Ms) as well as improved electrical properties.

Reduced graphene oxide as reinforcement in aluminium nanocomposites prepared by powder metallurgy

This study investigated the use of reduced graphene oxide (rGO) obtained by chemical route as a reinforcement phase in aluminium matrix nanocomposites (AMNCs) fabricated by powder metallurgy. Mechanical milling of a mixture of aluminium and rGO powders was able to form homogeneous and highly densified composites, allowing an effective interaction between matrix and reinforcement to establish. The effect of rGO content (ranging for 0.01 to 1.0 wt%) on the mechanical properties of rGO-AMNCs was investigated. Microhardness, elastic modulus and yield strength increase gradually up to 0.5 wt% with respective gains of 308%, 61% and 86%.

Physical, Corrosion and Microstructural Analysis of A356/SiC Nanocomposites Fabricated through Stir Casting Process

Porosity is one of the main difficulty to fabricate the superior quality of aluminium matrix composites (AMCs) because it effects the surface finish of the casting, mechanical properties and corrosion resistance. Therefore, porosity must be minimum as possible so that better casting can be produced with optimal properties of the composites. In this study, aluminium matrix nanocomposites (A356/SiC or AMNCs) were fabricated through two-step stir casting via mechanical alloying using ball mill. The matrix alloy (A356) was reinforced with SiC nanoparticles of 40-55 nm avarage particle size (APS). The corrosion was performed by simple immersion corrosion test method for a predefined environment (3.5% NaCl solution) and for the specified duration. The results showed that density and porosity increase with the addition of reinforcement. The corrosion resistance get reduced with the incorporation of SiC due to the increase in porosity and number of nucleation sites. The substantial correlation between the corrosion rate and the amount of SiC are depicted. Moreover, the corrosion rate decreased with the increase in exposure time which is due to the formation of passive layer. The EDS spectrum shows the presence of different constituents in the composites. The formation of the cracks, oxides, pitting corrosion, and localized corrosion are found by the SEM results. Further, SEM of the corroded surface verifies the presence and good distribution of the SiC nanoparticles in the fabricated nanocomposites.

Study the Effects of Titanium Dioxide nano particles reinforcement on the mechanical properties of Aluminum Alloys composite

Aluminum alloy6061 and 6082 was used as base material to the Aluminum matrix nano composites (AMNC ) and different Titanium Dioxide(TiO2) nano particles reinforcement wt. % of Ti(0.5, 1.0, 1.5and 2.0), the size of Titania reinforced material particles is 10 Nano meter, were been fabricated by using stir casting method. The effects of added nano particles on the mechanical properties of MMNC been studded. It was observed that the nanomaterial reinforcement led to high improvement in ultimate strength (σu), yield stress (σy), hardness (BHN) and ductility. The maximum improvement in ultimate strength, yield stress and BHN hardness was observed at 1.5 wt % TiO2 for Aluminum alloy6061 and 6082 while the maximum value of Elongation % was obtained at 0.5 wt. % TiO2 nano reinforcement for both Aluminum alloy6061 and 6082.

Deformation behavior and strengthening mechanisms in a CNT-reinforced bimodal-grained aluminum matrix nanocomposite

The aim of this study was to identify deformation behavior and strengthening mechanisms of a carbon nanotube (CNT)-reinforced bimodal-grained Al–Cu–Mg nanocomposite and its base alloy fabricated by two-step ball milling, powder metallurgy and extrusion. A superior strength-ductility synergy stemming from the concurrent presence of ultrafine grains (UFGs) and coarse grains (CGs) was achieved. Singly-dispersed CNTs in UFGs and sound CNT/Al interfacial bond contributed to a significant improvement in the strength of the nanocomposite. The predominant strengthening mechanism in the CNT-reinforced nanocomposite was identified to be Orowan looping due to severe shearing of CNTs into nano-sized fragments during ball milling, along with load-transfer and thermal mismatch-induced dislocation strengthening mechanisms. The predicted yield strength of the nanocomposite was in agreement with the experimental value obtained. The findings in this study help pave the way for developing high-performance lightweight materials with a superior strength-ductility synergy via incorporating CNTs with novel bimodal grain structures. • A novel bimodal CNT-reinforced 2009Al nanocomposite is successfully fabricated. • The concurrent presence of UFGs and CGs offers superior strength-ductility harmony. • CNTs are singly dispersed in the UFG regime with sound bond of CNT/Al interface. • 3 vol% CNTs in the nanocomposite lead to a significant strength improvement. • The predominant strengthening mechanism in the nanocomposite is Orowan looping.