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18 pages, 63874 KiB

Open AccessArticle

Microstructure and Mechanical Properties of Cu-CoatedCarbon-Nanotubes-Reinforced Aluminum Matrix Composites Fabricated by Ultrasonic-Assisted Casting

by Xiaojian Dong, Min Zeng and Hong Yan

Metals 2024, 14(3), 265; https://doi.org/10.3390/met14030265 - 22 Feb 2024

Cited by 1 | Viewed by 1111

Abstract

Carbon nanotubes (CNTs) are considered ideal nanoscale reinforcement for the development of high-performance metal matrix composites due to their unique structure and excellent mechanical properties. However, CNTs are easy to agglomerate and have poor wettability with the aluminum matrix, resulting in unsatisfactory effects [...] Read more.

Carbon nanotubes (CNTs) are considered ideal nanoscale reinforcement for the development of high-performance metal matrix composites due to their unique structure and excellent mechanical properties. However, CNTs are easy to agglomerate and have poor wettability with the aluminum matrix, resulting in unsatisfactory effects when added to the aluminum melt. In this study, Cu-coated carbon nanotubes (Cu@CNTs)-reinforced aluminum matrix composites were fabricated by high-energy ultrasonic-assisted casting. Moreover, the effects of different Cu@CNTs content on the microstructure and mechanical properties of aluminum matrix composites were explored. Meanwhile, Fluent 19.0 software was used to further explore the function of ultrasonic vibration in the melt. The results demonstrated that the mechanical properties of composite with 1.2 wt% Cu@CNTs are optimal. Compared with the matrix, the composite with 1.2 wt% Cu@CNTs displayed a 39.3% increase in yield strength, 53.5% increase in ultimate tensile strength, and 5.7% increase in elongation. The simulation results showed that the uniform dispersion of Cu@CNTs and grain refinement can be attributed to the acoustic streaming effect and cavitation effect of high-energy ultrasound. The improvement of the properties of the composites can be attributed to the grain refinement and the load-bearing effect of CNTs. Full article

(This article belongs to the Special Issue Advances in Lightweight Metal Matrix Composites)

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16 pages, 8611 KiB

Open AccessArticle

Effects of Graphite Particle Content and Holding Time on the Microstructure and Mechanical Properties of the Graphite/AZ91D Composite

by Xin Gao, Kejian Geng, Cuicui Sun, Suqing Zhang, Jixue Zhou, Jianhua Wu, Xinfang Zhang and Xitao Wang

Metals 2023, 13(1), 57; https://doi.org/10.3390/met13010057 - 25 Dec 2022

Cited by 5 | Viewed by 1373

Abstract

The effects of Grp (graphite particles) addition and holding time on the microstructure and mechanical properties of the Grp/AZ91D composite were investigated in this work. The results indicated that the distribution of Grp in the matrix was determined by the self-stabilizing mechanism and [...] Read more.

The effects of Grp (graphite particles) addition and holding time on the microstructure and mechanical properties of the Grp/AZ91D composite were investigated in this work. The results indicated that the distribution of Grp in the matrix was determined by the self-stabilizing mechanism and relationships between the solidifying interface and the particles. Due to the self-stabilizing mechanism, a small amount of Grp would uniformly distribute in the melt alloy, and as the amount of Grp increased, agglomeration would occur. Accordingly, the former would be engulfed by the solidifying interface and the latter would be pushed. With an increased holding time, Grp tended to agglomerate, due to the interfacial reaction that occurred, and as a result, the solidifying interface will push it. The Grp/AZ91D composite with the addition of 1.5 wt.% Grp and a holding time of 15 min obtained grains 30.2 μm in size with a hardness of 89.07 HV, which was a decrease of 83.04% and increase of 35.06% compared to AZ91D, respectively. Full article

(This article belongs to the Special Issue Advances in Lightweight Metal Matrix Composites)

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24 pages, 13783 KiB

Open AccessArticle

Effect of Carbon Nanotube Content and Mechanical Milling Conditions on the Manufacture of AA7075/MWCNT Composites

by Iria Feijoo, Gloria Pena, María Julia Cristóbal, Marta Cabeza and Pilar Rey

Metals 2022, 12(6), 1020; https://doi.org/10.3390/met12061020 - 16 Jun 2022

Cited by 2 | Viewed by 1946

Abstract

Aluminium matrix composites (AlMCs) of AA7075 aluminium alloy reinforced with 0.5 and 1 wt.% multiwall carbon nanotubes (MWCNTs) were fabricated with powder metallurgy techniques using three different mechanical milling strategies, varying the milling energy and the stage in which the reinforcements were added [...] Read more.

Aluminium matrix composites (AlMCs) of AA7075 aluminium alloy reinforced with 0.5 and 1 wt.% multiwall carbon nanotubes (MWCNTs) were fabricated with powder metallurgy techniques using three different mechanical milling strategies, varying the milling energy and the stage in which the reinforcements were added to the pre-alloyed matrix powders. In this paper, we focus on the influence of these parameters on the dispersion of MWCNTs. Characterization of the obtained composite powders by X-ray diffraction and scanning electron microscopy showed that the evolution of the particle size and morphology of the composite powders is influenced by milling conditions and MWCNT content; however, under the conditions tested in this study, there were no significant differences in crystallite size and lattice strain. The best distribution of the reinforcements was obtained after milling 7075 powders and MWCNTs in a high-energy cycle (HEBM), varying the rotation speed between 1200 and 1300 rpm. Raman spectroscopy was used to assess the damage induced by the milling process in the nanotubes, and no reaction products were detected under any of the tested conditions. Nanoindentation tests were performed to measure the elastic modulus and hardness of the composite powders, revealing that the best mechanical behaviour was achieved by the 7075-0.5 wt.% MWCNT composites obtained by the HEBM route. Full article

(This article belongs to the Special Issue Advances in Lightweight Metal Matrix Composites)

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13 pages, 5373 KiB

Open AccessArticle

Influence of Different Addition Ratios of Fly Ash on Mechanical Properties of ADC10 Aluminum Matrix Composites

by Shueiwan Henry Juang and Ching-Feng Li

Metals 2022, 12(4), 653; https://doi.org/10.3390/met12040653 - 11 Apr 2022

Cited by 4 | Viewed by 2012

Abstract

Aluminum-fly ash composites are formed by the chemical reaction between fly ash and the high-temperature aluminum-based alloy, which melts to form aluminum oxide as a reinforcing phase, which belongs to a composite of in situ synthetic reinforcing phases. Compared to aluminum-based alloys, composites [...] Read more.

Aluminum-fly ash composites are formed by the chemical reaction between fly ash and the high-temperature aluminum-based alloy, which melts to form aluminum oxide as a reinforcing phase, which belongs to a composite of in situ synthetic reinforcing phases. Compared to aluminum-based alloys, composites have superior strength, rigidity, damping capacity, and wear resistance, but lower ductility and toughness. In this study, different fly ash addition ratios (0, 3, 6, 9, 12, and 15 wt%) were added to the ADC10-2Mg alloy melt via stir casting to form the aluminum-fly ash composite under the chemical reaction at 800 °C for 30 h. Subsequently, microstructure observation, density and porosity measurements, and hardness and tensile tests were conducted to analyze the influence of different fly ash weight percentages on the mechanical properties of aluminum-fly ash composites. According to the results, an aluminum-fly ash composite with good dispersibility of fly ash debris can be prepared by stir casting, and the fly ash particles gradually decomposed small debris as they reacted with the aluminum-based alloy at high temperatures during a long-term reaction process. The density of the aluminum–fly ash composite was reduced by adding fly ash, and its hardness and tensile strength were improved as well. However, the porosity increased with the amount of fly ash and the ductility was diminished. For the aluminum-fly ash composite with 6 wt% of fly ash, its density decreased by approximately 2%, the hardness and tensile strength increased by 7% and 49%, respectively, and the ductility decreased by 35%, as compared to those of the ADC10 alloy. Full article

(This article belongs to the Special Issue Advances in Lightweight Metal Matrix Composites)

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12 pages, 2271 KiB

Open AccessFeature PaperArticle

An Experimental Investigation on the Material Removal Rate and Surface Roughness of a Hybrid Aluminum Metal Matrix Composite (Al6061/SiC/Gr)

by Mandeep Singh, Harish Kumar Garg, Sthitapragyan Maharana, Anchal Yadav, Rasmeet Singh, Pragyansu Maharana, Tien V. T. Nguyen, Sudesh Yadav and M. K. Loganathan

Metals 2021, 11(9), 1449; https://doi.org/10.3390/met11091449 - 13 Sep 2021

Cited by 33 | Viewed by 4942 | Correction

Abstract

The objective of this paper was to determine the optimum process parameters of an electric discharge machine while machining a new hybrid aluminum metal matrix composite. In this study, a new hybrid aluminum metal matrix composite was prepared, with silicon carbide and graphite [...] Read more.

The objective of this paper was to determine the optimum process parameters of an electric discharge machine while machining a new hybrid aluminum metal matrix composite. In this study, a new hybrid aluminum metal matrix composite was prepared, with silicon carbide and graphite particles used as reinforcements, with the help of the stir casting method. The selected electric discharge machining parameters in this study were peak current (I), voltage (V), pulse-on time (T_on), and tool material, while the response parameters were material removal rate and surface roughness. To machine the fabricated samples, two different types of tool materials (copper and brass) were used as electric discharge machine electrodes, and each had a diameter (Ø) of 12.0 mm. The optimal settings of the electric discharge machining parameters were determined through experiments planned, conducted, and analyzed using the Taguchi (L₁₈) technique. An analysis of variance and confirmatory tests were used to check the contribution of each machining parameter. It was found that the material removal rate increased with the increase in pulse-on time and pulse current, whereas the material removal rate decreased with the increase in voltage. On the other hand, reduced surface roughness could only be achieved when current, voltage, and pulse duration were low. It was also found that the selected electric discharge machining electrodes had a significant effect on both the material removal rate and the surface roughness. Full article

(This article belongs to the Special Issue Advances in Lightweight Metal Matrix Composites)

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11 pages, 4270 KiB

Open AccessArticle

On the Strength of the CF/Al-Wire Depending on the Fabrication Process Parameters: Melt Temperature, Time, Ultrasonic Power, and Thickness of Carbon Fiber Coating

by Sergei Galyshev

Metals 2021, 11(7), 1006; https://doi.org/10.3390/met11071006 - 24 Jun 2021

Cited by 9 | Viewed by 1716

Abstract

The process of the production of a CF/Al-wire by pulling carbon fibers through an aluminum melt has at least 15 parameters. The main parameters include the power of ultrasonic treatment, the time of contact of the fiber with the matrix melt, and the [...] Read more.

The process of the production of a CF/Al-wire by pulling carbon fibers through an aluminum melt has at least 15 parameters. The main parameters include the power of ultrasonic treatment, the time of contact of the fiber with the matrix melt, and the melt temperature. In addition, the presence of a barrier coating on the fiber surface and its thickness significantly affects the properties of the resulting material. The importance of these parameters is due to their direct effect on the chemical interaction between the aluminum matrix and the carbon fiber. This interaction leads to the formation of aluminum carbide, a hygroscopic, brittle phase that ultimately significantly reduces the strength of such composites. In this regard, limiting a chemical reaction at the matrix/fiber interface in the production of CF/Al composites is one of the main technological problems. The main goal of this work is to pragmatically elucidate the effect of the above parameters on the strength of CF/Al composites. It is shown that the strength of a CF/Al-wire can reach 2000 MPa. Full article

(This article belongs to the Special Issue Advances in Lightweight Metal Matrix Composites)

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11 pages, 5429 KiB

Open AccessArticle

Laser Beam Welding of a Ti-15Mo/TiB Metal–Matrix Composite

by Maxim Ozerov, Elizaveta Povolyaeva, Nikita Stepanov, Volker Ventzke, René Dinse, Nikolai Kashaev and Sergey Zherebtsov

Metals 2021, 11(3), 506; https://doi.org/10.3390/met11030506 - 18 Mar 2021

Cited by 16 | Viewed by 2521

Abstract

A Ti-15Mo/TiB metal–matrix composite was produced by spark plasma sintering at 1400 °C. The fractions of the elements in the initial powder mixture were 80.75 wt.% Ti, 14.25 wt.% Mo, and 5 wt.% TiB₂. The initial structure of the synthesized composite [...] Read more.

A Ti-15Mo/TiB metal–matrix composite was produced by spark plasma sintering at 1400 °C. The fractions of the elements in the initial powder mixture were 80.75 wt.% Ti, 14.25 wt.% Mo, and 5 wt.% TiB₂. The initial structure of the synthesized composite was composed of bcc β titanium matrix and needle-like TiB reinforcements with an average thickness of 500 ± 300 nm. Microstructure and mechanical properties of the composite were studied after laser beam welding (LBW) was carried out at room temperature or various pre-heating temperatures: 200, 400, or 600 °C. The quality of laser beam welded joints was not found to be dependent noticeably on the pre-heating temperature; all welds consisted of pores the size of which reached 200–300 µm. In contrast to acicular individual particles in the base material, TiB whiskers in the weld zone were found to have a form of bunches. The maximum microhardness in the weld zone (~700 HV) was obtained after welding at room temperature or at 200 °C; this value was ~200 HV higher than that in the base material. Full article

(This article belongs to the Special Issue Advances in Lightweight Metal Matrix Composites)

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1 pages, 152 KiB

Open AccessCorrection

Correction: Singh et al. An Experimental Investigation on the Material Removal Rate and Surface Roughness of a Hybrid Aluminum Metal Matrix Composite (Al6061/SiC/Gr). Metals 2021, 11, 1449

by Mandeep Singh, Harish Kumar Garg, Sthitapragyan Maharana, Anchal Yadav, Rasmeet Singh, Pragyansu Maharana, Tien V. T. Nguyen, Sudesh Yadav and M. K. Loganathan

Metals 2022, 12(4), 550; https://doi.org/10.3390/met12040550 - 24 Mar 2022

Cited by 3 | Viewed by 1320

Abstract

Harish Kumar Garg was not included as an author in the published article [...] Full article

(This article belongs to the Special Issue Advances in Lightweight Metal Matrix Composites)

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