Metal Matrix Composites

A special issue of Metals (ISSN 2075-4701).

Deadline for manuscript submissions: closed (31 December 2017) | Viewed by 114872

Special Issue Editor

Materials Group, Department of Mechanical Engineering, National University of Singapore, 9 Engineering Drive 1, Singapore 117576, Singapore
Interests: metal additive manufacturing; processing; characterization; lightweight materials; nanocomposites
Special Issues, Collections and Topics in MDPI journals

Special Issue Information

Dear Colleagues,

Metal matrix composites are emerging as critical materials in engineering and biomedical applications due to their capability to be tailored in terms of engineering properties. With a history of about four decades, researchers have been able to establish synthesis methods for metal-based composites containing reinforcements in the range from micron-length scale to nano-length scale. Current research in the area of nanocomposites, for example, is perhaps the most intriguing. Similarly, the emergence of magnesium and new alloys have opened new challenges for researchers to advance in the area of metal-based composites. Accordingly, the main aim of this Special Issue is to provide a platform for researchers worldwide to showcase their work in the domains of synthesis, characterization, modelling and applications of metal-based composites.

Professor Manoj Gupta
Guest Editor

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Keywords

  • Metals
  • reinforcement
  • processing
  • microstructure
  • mechanical properties
  • corrosion
  • nanocomposites
  • modelling

Published Papers (21 papers)

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Editorial

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2 pages, 132 KiB  
Editorial
Metal Matrix Composites
by Manoj Gupta
Metals 2018, 8(6), 379; https://0-doi-org.brum.beds.ac.uk/10.3390/met8060379 - 24 May 2018
Cited by 2 | Viewed by 2277
(This article belongs to the Special Issue Metal Matrix Composites)

Research

Jump to: Editorial, Review

17 pages, 3427 KiB  
Article
Magnesium-β-Tricalcium Phosphate Composites as a Potential Orthopedic Implant: A Mechanical/Damping/Immersion Perspective
by Gururaj Parande, Vyasaraj Manakari, Harshit Gupta and Manoj Gupta
Metals 2018, 8(5), 343; https://0-doi-org.brum.beds.ac.uk/10.3390/met8050343 - 11 May 2018
Cited by 33 | Viewed by 4767
Abstract
The design and development of novel magnesium-based materials with suitable alloying elements and bio-ceramic reinforcements can act as a possible solution to the ever-increasing demand of high performance bioresorbable orthopedic implant. In the current study, Mg-β-tricalcium phosphate composites are synthesized using the hybrid [...] Read more.
The design and development of novel magnesium-based materials with suitable alloying elements and bio-ceramic reinforcements can act as a possible solution to the ever-increasing demand of high performance bioresorbable orthopedic implant. In the current study, Mg-β-tricalcium phosphate composites are synthesized using the hybrid powder metallurgy technique, followed by hot extrusion. The influence of addition of (0.5, 1, and 1.5) vol % β-tricalcium phosphate on the mechanical, damping, and immersion characteristics of pure magnesium are studied. The addition of β-tricalcium phosphate enhanced the yield strength, ultimate compressive strength, and compressive fracture strain of pure magnesium by about ~34%, ~53%, and ~22%, respectively. Also, Mg 1.5 vol % β-tricalcium phosphate composite exhibited a ~113% enhancement in the damping characteristics when compared to pure magnesium. A superior ~70% reduction in the grain size was observed by the addition of 1.5 vol % β-tricalcium phosphate particles to pure Mg. The response of Mg-β-tricalcium phosphate composites is studied under the influence of chloride environment using Hanks’ balanced salt solution. The dynamic passivation was realized faster for the composite samples as compared to pure Mg, which resulted in decreased corrosion rates with the addition of β-tricalcium phosphate particles to pure Mg. Full article
(This article belongs to the Special Issue Metal Matrix Composites)
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10 pages, 5773 KiB  
Article
Enhancing the Hardness and Compressive Response of Magnesium Using Complex Composition Alloy Reinforcement
by Khin Sandar Tun, Yuming Zhang, Gururaj Parande, Vyasaraj Manakari and Manoj Gupta
Metals 2018, 8(4), 276; https://0-doi-org.brum.beds.ac.uk/10.3390/met8040276 - 17 Apr 2018
Cited by 18 | Viewed by 3910
Abstract
The present study reports the development of new magnesium composites containing complex composition alloy (CCA) particles. Materials were synthesized using a powder metallurgy route incorporating hybrid microwave sintering and hot extrusion. The presence and variation in the amount of ball-milled CCA particles (2.5 [...] Read more.
The present study reports the development of new magnesium composites containing complex composition alloy (CCA) particles. Materials were synthesized using a powder metallurgy route incorporating hybrid microwave sintering and hot extrusion. The presence and variation in the amount of ball-milled CCA particles (2.5 wt %, 5 wt %, and 7.5 wt %) in a magnesium matrix and their effect on the microstructure and mechanical properties of Mg-CCA composites were investigated. The use of CCA particle reinforcement effectively led to a significant matrix grain refinement. Uniformly distributed CCA particles were observed in the microstructure of the composites. The refined microstructure coupled with the intrinsically high hardness of CCA particles (406 HV) contributed to the superior mechanical properties of the Mg-CCA composites. A microhardness of 80 HV was achieved in a Mg-7.5HEA (high entropy alloy) composite, which is 1.7 times higher than that of pure Mg. A significant improvement in compressive yield strength (63%) and ultimate compressive strength (79%) in the Mg-7.5CCA composite was achieved when compared to that of pure Mg while maintaining the same ductility level. When compared to ball-milled amorphous particle-reinforced and ceramic-particle-reinforced Mg composites, higher yield and compressive strengths in Mg-CCA composites were achieved at a similar ductility level. Full article
(This article belongs to the Special Issue Metal Matrix Composites)
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13 pages, 9264 KiB  
Article
Elastic and Plastic Behavior of the QE22 Magnesium Alloy Reinforced with Short Saffil Fibers and SiC Particles
by Josef Zapletal, Zuzanka Trojanová, Pavel Doležal, Stanislava Fintová and Michal Knapek
Metals 2018, 8(2), 133; https://0-doi-org.brum.beds.ac.uk/10.3390/met8020133 - 15 Feb 2018
Cited by 4 | Viewed by 4103
Abstract
Magnesium alloy QE22 (nominal composition 2 wt % Ag, 2 wt % mixture of rare earth elements, balance Mg) was reinforced with 5 vol % Saffil fibers and 15 vol % SiC particles. The hybrid composite was prepared via the squeeze cast technique. [...] Read more.
Magnesium alloy QE22 (nominal composition 2 wt % Ag, 2 wt % mixture of rare earth elements, balance Mg) was reinforced with 5 vol % Saffil fibers and 15 vol % SiC particles. The hybrid composite was prepared via the squeeze cast technique. The microstructure of the monolithic alloy and composite was analyzed using scanning electron microscopy. Elastic modulus was measured at room temperature and modeled by the Halpin–Tsai–Kardos mathematical model. The strengthening effect of fibers and particles was calculated and compared with the experimentally obtained values. The main strengthening terms were determined. Fracture surfaces were studied via scanning electron microscope. While the fracture of the matrix alloy had a mainly intercrystalline character, the failure of the hybrid composite was transcrystalline. Full article
(This article belongs to the Special Issue Metal Matrix Composites)
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13 pages, 17505 KiB  
Article
Mechanical Properties of Thixoforged In Situ Mg2Sip/AM60B Composite at Elevated Temperatures
by Suqing Zhang, Tijun Chen, Jixue Zhou, Dapeng Xiu, Tao Li and Kaiming Cheng
Metals 2018, 8(2), 106; https://0-doi-org.brum.beds.ac.uk/10.3390/met8020106 - 02 Feb 2018
Cited by 3 | Viewed by 3242
Abstract
The mechanical behaviors of the thixoforged in situ Mg2Sip/AM60B composite at elevated temperatures were evaluated. The results indicated that the thixoforged composite exhibits higher UTS (ultimate tensile strength) than that of the thixoforged AM60B at the cost of elongation. [...] Read more.
The mechanical behaviors of the thixoforged in situ Mg2Sip/AM60B composite at elevated temperatures were evaluated. The results indicated that the thixoforged composite exhibits higher UTS (ultimate tensile strength) than that of the thixoforged AM60B at the cost of elongation. As the testing temperature rises from 25 to 300 °C, the UTS of both these two materials decreases while their elongations increases. The enhanced dislocation motion ability, the softened eutectic β phase at 120 °C, the activated non-basal slipping and the dynamic recovery and recrystallization mechanisms at 150 °C are responsible for the change in tensile properties with testing temperatures. The fracture mode transforms from the ductile into the brittle as the initial strain rate increases from 0.01 to 0.2 s−1 at 200 °C. Full article
(This article belongs to the Special Issue Metal Matrix Composites)
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4881 KiB  
Article
New Nanocomposite Materials with Improved Mechanical Strength and Tailored Coefficient of Thermal Expansion for Electro-Packaging Applications
by Abdollah Saboori, Seyed Kiomars Moheimani, Matteo Pavese, Claudio Badini and Paolo Fino
Metals 2017, 7(12), 536; https://0-doi-org.brum.beds.ac.uk/10.3390/met7120536 - 01 Dec 2017
Cited by 28 | Viewed by 5657
Abstract
In this research, copper nanocomposites reinforced by graphene nanoplatelets (GNPs) were fabricated using a wet mixing method followed by a classical powder metallurgy route. In order to find the best dispersion technique, ball milling and wet mixing were chosen. Qualitative evaluation of the [...] Read more.
In this research, copper nanocomposites reinforced by graphene nanoplatelets (GNPs) were fabricated using a wet mixing method followed by a classical powder metallurgy route. In order to find the best dispersion technique, ball milling and wet mixing were chosen. Qualitative evaluation of the structure of the graphene after mixing indicated that the wet mixing is an appropriate technique to disperse the GNPs. Thereafter, the influence of graphene content on microstructure, density, hardness, elastic modulus, and thermal expansion coefficient of composites was investigated. It was shown that by increasing the graphene content the aggregation of graphene is more obvious and, thus, these agglomerates affect the final properties adversely. In comparison with the unreinforced Cu, Cu–GNP composites were lighter, and their hardness and Young’s modulus were higher as a consequence of graphene addition. According to the microstructural observation of pure copper and its composites after sintering, it was concluded that grain refinement is the main mechanism of strengthening in this research. Apart from the mechanical characteristics, the coefficient of thermal expansion of composites decreased remarkably and the combination of this feature with appropriate mechanical properties can make them a promising candidate for use in electronic packaging applications. Full article
(This article belongs to the Special Issue Metal Matrix Composites)
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15211 KiB  
Article
Reduced Graphene Oxide Reinforced 7075 Al Matrix Composites: Powder Synthesis and Mechanical Properties
by Youhong Sun, Chi Zhang, Baochang Liu, Qingnan Meng, Shaoming Ma and Wenhao Dai
Metals 2017, 7(11), 499; https://0-doi-org.brum.beds.ac.uk/10.3390/met7110499 - 13 Nov 2017
Cited by 20 | Viewed by 6648
Abstract
Reduced graphene oxide (rGO) reinforced 7075 Al matrix composites were fabricated by electrostatic self-assembly and powder metallurgy. 7075 Al powders were surface modified by introducing a cetyl trimethyl ammonium bromide (CTAB) membrane on the surface, which was able to form a strong bonding [...] Read more.
Reduced graphene oxide (rGO) reinforced 7075 Al matrix composites were fabricated by electrostatic self-assembly and powder metallurgy. 7075 Al powders were surface modified by introducing a cetyl trimethyl ammonium bromide (CTAB) membrane on the surface, which was able to form a strong bonding with graphene oxide (GO) through electrostatic interaction. During the vacuum sintering process, CTAB was effectively removed and GO was thermally reduced into rGO. Morphologies of GO nanosheets, GO/7075 Al powders, microstructures, and tensile fractographs of the composites were observed. The effect of rGO content on mechanical properties of rGO/7075 Al composites was investigated. The results show that a good bonding between rGO and matrix is achieved. With the rGO content increasing, the hardness increases gradually, while the ultimate tensile strength and yield strength initially increase and later decrease. The improvement in strength of rGO/7075 Al composites was attributed to stress transfer and dislocation strengthening. With rGO content reaching 0.50 wt %, the excessive addition of rGO gave rise to a weakening in the enhancement of the tensile properties due to the increasing amounts of brittle Al4C3 and cracks. Full article
(This article belongs to the Special Issue Metal Matrix Composites)
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14913 KiB  
Article
Study of the Influence of TiB Content and Temperature in the Properties of In Situ Titanium Matrix Composites
by Cristina Arévalo, Isabel Montealegre-Melendez, Eva M. Pérez-Soriano, Enrique Ariza, Michael Kitzmantel and Erich Neubauer
Metals 2017, 7(11), 457; https://0-doi-org.brum.beds.ac.uk/10.3390/met7110457 - 27 Oct 2017
Cited by 4 | Viewed by 3795
Abstract
This work focuses on the study of the microstructure, hardening, and stiffening effect caused by the secondary phases formed in titanium matrices. These secondary phases originated from reactions between the matrix and boron particles added in the starting mixtures of the composites. Not [...] Read more.
This work focuses on the study of the microstructure, hardening, and stiffening effect caused by the secondary phases formed in titanium matrices. These secondary phases originated from reactions between the matrix and boron particles added in the starting mixtures of the composites. Not only was the composite composition studied as an influencing factor in the behaviour of the composites, but also different operational temperatures. Three volume percentages of boron content were tested (0.9 vol %, 2.5 vol %, and 5 vol % of amorphous boron). The manufacturing process used to produce the composites was inductive hot pressing, which operational temperatures were between 1000 and 1300 °C. Specimens showed optimal densification. Moreover, microstructural studies revealed the formation of TiB in various shapes and proportions. Mechanical testing confirmed that the secondary phases had a positive influence on properties of the composites. In general, adding boron particles increased the hardness and stiffness of the composites; however rising temperatures resulted in greater increases in stiffness than in hardness. Full article
(This article belongs to the Special Issue Metal Matrix Composites)
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2496 KiB  
Article
Ultrasound Assisted Casting of an AM60 Based Metal Matrix Nanocomposite, Its Properties, and Recyclability
by Hajo Dieringa, Lydia Katsarou, Ricardo Buzolin, Gábor Szakács, Manfred Horstmann, Martin Wolff, Chamini Mendis, Sergey Vorozhtsov and David StJohn
Metals 2017, 7(10), 388; https://0-doi-org.brum.beds.ac.uk/10.3390/met7100388 - 22 Sep 2017
Cited by 44 | Viewed by 5628
Abstract
An AM60 magnesium alloy nanocomposite reinforced with 1 wt % of AlN nanoparticles was prepared using an ultrasound (US) assisted permanent-mould indirect-chill casting process. Ultrasonically generated cavitation and acoustic streaming promoted de-agglomeration of particle clusters and distributed the particles throughout the melt. Significant [...] Read more.
An AM60 magnesium alloy nanocomposite reinforced with 1 wt % of AlN nanoparticles was prepared using an ultrasound (US) assisted permanent-mould indirect-chill casting process. Ultrasonically generated cavitation and acoustic streaming promoted de-agglomeration of particle clusters and distributed the particles throughout the melt. Significant grain refinement due to nucleation on the AlN nanoparticles was accompanied by an exceptional improvement in properties: yield strength increased by 103%, ultimate tensile strength by 115%, and ductility by 140%. Although good grain refinement was observed, the large nucleation undercooling of 14 K limits further refinement because nucleation is prevented by the formation of a nucleation-free zone around each grain. To assess the industrial applicability and recyclability of the nanocomposite material in various casting processes, tests were performed to determine the effect of remelting on the microstructure. With each remelting, a small percentage of effective AlN nanoparticles was lost, and some grain growth was observed. However, even after the third remelting, excellent strength and ductility was retained. According to strengthening models, enhanced yield strength is mainly attributed to Hall-Petch strengthening caused by the refined grain size. A small additional contribution to strengthening is attributed to Orowan strengthening. Full article
(This article belongs to the Special Issue Metal Matrix Composites)
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2523 KiB  
Article
Significantly Enhancing the Ignition/Compression/Damping Response of Monolithic Magnesium by Addition of Sm2O3 Nanoparticles
by Milli Suchita Kujur, Ashis Mallick, Vyasaraj Manakari, Gururaj Parande, Khin Sandar Tun and Manoj Gupta
Metals 2017, 7(9), 357; https://0-doi-org.brum.beds.ac.uk/10.3390/met7090357 - 09 Sep 2017
Cited by 54 | Viewed by 6109
Abstract
The present study reports the development of Mg–Sm2O3 nanocomposites as light-weight materials for weight critical applications targeted to reduce CO2 emissions, particularly in the transportation sector. Mg-0.5, 1.0, and 1.5 vol % Sm2O3 nanocomposites are synthesized [...] Read more.
The present study reports the development of Mg–Sm2O3 nanocomposites as light-weight materials for weight critical applications targeted to reduce CO2 emissions, particularly in the transportation sector. Mg-0.5, 1.0, and 1.5 vol % Sm2O3 nanocomposites are synthesized using a powder metallurgy method incorporating hybrid microwave sintering and hot extrusion. The microstructural studies showed dispersed Sm2O3 nanoparticles (NPs), refinement of grain size due to the presence of Sm2O3 NPs, and presence of limited porosity. Microhardness and dimensional stability of pure Mg increased with the progressive addition of Sm2O3 NPs. The addition of 1.5 vol % of Sm2O3 NPs to the Mg matrix enhanced the ignition temperature by ~69 °C. The ability of pure Mg to absorb vibration also progressively enhanced with the addition of Sm2O3 NPs. The room temperature compressive strengths (CYS and UCS) of Mg–Sm2O3 nanocomposites were found to be higher without having any adverse effect on ductility, leading to a significant increase in energy absorbed prior to compressive failure. Further, microstructural characteristics are correlated with the enhancement of various properties exhibited by nanocomposites. Full article
(This article belongs to the Special Issue Metal Matrix Composites)
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4505 KiB  
Article
Aluminum and Nickel Matrix Composites Reinforced by CNTs: Dispersion/Mixture by Ultrasonication
by Sónia Simões, Filomena Viana, Marcos A. L. Reis and Manuel F. Vieira
Metals 2017, 7(7), 279; https://0-doi-org.brum.beds.ac.uk/10.3390/met7070279 - 22 Jul 2017
Cited by 49 | Viewed by 7343
Abstract
The main challenge in the production of metal matrix composites reinforced by carbon nanotubes (CNTs) is the development of a manufacturing process ensuring the dispersion of nanoparticles without damaging them, and the formation of a strong bond with the metallic matrix to achieve [...] Read more.
The main challenge in the production of metal matrix composites reinforced by carbon nanotubes (CNTs) is the development of a manufacturing process ensuring the dispersion of nanoparticles without damaging them, and the formation of a strong bond with the metallic matrix to achieve an effective load transfer, so that the maximum reinforcement effect of CNTs will be accomplished. This research focuses on the production by powder metallurgy of aluminum and nickel matrix composites reinforced by CNTs, using ultrasonication as the dispersion and mixture process. Microstructural characterization of nanocomposites was performed by optical microscopy (OM), scanning and transmission electron microscopy (SEM and TEM), electron backscattered diffraction (EBSD) and high-resolution transmission electron microscopy (HRTEM). Microstructural characterization revealed that the use of ultrasonication as the dispersion and mixture process in the production of Al/CNT and Ni/CNT nanocomposites promoted the dispersion and embedding of individual CNT in the metallic matrices. CNT clusters at grain boundary junctions were also observed. The strengthening effect of the CNTs is shown by the increase in hardness for all nanocomposites. The highest hardness values were observed for Al/CNT and Ni/CNT nanocomposites, with a 1.00 vol % CNTs. Full article
(This article belongs to the Special Issue Metal Matrix Composites)
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8636 KiB  
Article
Comparative Investigation of Tungsten Fibre Nets Reinforced Tungsten Composite Fabricated by Three Different Methods
by Linhui Zhang, Yan Jiang, Qianfeng Fang, Rui Liu, Zhuoming Xie, Tao Zhang, Xianping Wang and Changsong Liu
Metals 2017, 7(7), 249; https://0-doi-org.brum.beds.ac.uk/10.3390/met7070249 - 04 Jul 2017
Cited by 7 | Viewed by 4337
Abstract
Tungsten fibre nets reinforced tungsten composites (Wf/W) containing four net layers were fabricated by spark plasma sintering (SPS), hot pressing (HP) and cold rolling after HP (HPCR), with the weight fraction of fibres being 17.4%, 10.5% and 10.5%, respectively. The relative [...] Read more.
Tungsten fibre nets reinforced tungsten composites (Wf/W) containing four net layers were fabricated by spark plasma sintering (SPS), hot pressing (HP) and cold rolling after HP (HPCR), with the weight fraction of fibres being 17.4%, 10.5% and 10.5%, respectively. The relative density of the HPCRed samples is the highest (99.8%) while that of the HPed composites is the lowest (95.1%). Optical and scanning electron microscopy and electron back scattering diffraction were exploited to characterize the microstructure, while tensile and hardness tests were used to evaluate the mechanical properties of the samples. It was found that partial recrystallization of fibres occurred after the sintering at 1800 °C. The SPSed and HPed Wf/W composites begin to exhibit plastic deformation at 600 °C with tensile strength (TS) of 536 and 425 MPa and total elongation at break (TE) of 11.6% and 23.0%, respectively, while the HPCRed Wf/W composites exhibit plastic deformation at around 400 °C. The TS and TE of the HPCRed Wf/W composites at 400 °C are 784 MPa and 8.4%, respectively. The enhanced mechanical performance of the Wf/W composites over the pure tungsten can be attributed to the necking, cracking, and debonding of the tungsten fibres. Full article
(This article belongs to the Special Issue Metal Matrix Composites)
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2906 KiB  
Article
Transparent Conducting Film Fabricated by Metal Mesh Method with Ag and Cu@Ag Mixture Nanoparticle Pastes
by Hyun Min Nam, Duck Min Seo, Hyung Duk Yun, Gurunathan Thangavel, Lee Soon Park and Su Yong Nam
Metals 2017, 7(5), 176; https://0-doi-org.brum.beds.ac.uk/10.3390/met7050176 - 16 May 2017
Cited by 10 | Viewed by 6479
Abstract
Transparent conducting electrode film is highly desirable for application in touch screen panels (TSPs), flexible and wearable displays, sensors, and actuators. A sputtered film of indium tin oxide (ITO) shows high transmittance (90%) at low sheet resistance (50 Ω/cm2). However, ITO [...] Read more.
Transparent conducting electrode film is highly desirable for application in touch screen panels (TSPs), flexible and wearable displays, sensors, and actuators. A sputtered film of indium tin oxide (ITO) shows high transmittance (90%) at low sheet resistance (50 Ω/cm2). However, ITO films lack mechanical flexibility, especially under bending stress, and have limitation in application to large-area TSPs (over 15 inches) due to the trade-off in high transmittance and low sheet resistance properties. One promising solution is to use metal mesh-type transparent conducting film, especially for touch panel application. In this work, we investigated such inter-related issues as UV imprinting process to make a trench layer pattern, the synthesis of core-shell-type Ag and Cu@Ag composite nanoparticles and their paste formulation, the filling of Ag and Cu@Ag mixture nanoparticle paste to the trench layer, and touch panel fabrication processes. Full article
(This article belongs to the Special Issue Metal Matrix Composites)
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4200 KiB  
Article
Mechanical and Corrosion Behavior of Al-Zn-Cr Family Alloys
by Ahmed Nassef, Waleed H. El-Garaihy and Medhat El-Hadek
Metals 2017, 7(5), 171; https://0-doi-org.brum.beds.ac.uk/10.3390/met7050171 - 12 May 2017
Cited by 6 | Viewed by 4766
Abstract
Aluminum base alloys containing chromium (Cr) and zinc (Zn) were produced using extrusion and powder metallurgy techniques. Cr additions ranged between 5 to 10 wt. %, while Zn was added in an amount between 0 and 20 wt. %. Heat treatment processes were [...] Read more.
Aluminum base alloys containing chromium (Cr) and zinc (Zn) were produced using extrusion and powder metallurgy techniques. Cr additions ranged between 5 to 10 wt. %, while Zn was added in an amount between 0 and 20 wt. %. Heat treatment processes were performed during powder metallurgy process, at different temperatures, followed by water quenching. Similar alloys were extruded with an extrusion ratio of 4.6 to get proper densification. Optical microscopy was used for microstructure investigations of the alloys investigated. The element distribution microstructure study was carried out using the Energy Dispersive X-ray analysis method. Hardness and tensile properties of the investigated alloys have been examined. Wear resistance tests were carried out and the results were compared with these of the Al-based bulk alloys. Results showed that the aluminum base alloys, containing 10 wt. % Cr and heat treated at 500 °C for one hour followed by water quenching, exhibited the highest wear resistance and better mechanical properties. Full article
(This article belongs to the Special Issue Metal Matrix Composites)
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5100 KiB  
Article
Characteristics of Cold and Hot Pressed Iron Aluminum Powder Metallurgical Alloys
by Ahmed Nassef, Waleed H. El-Garaihy and Medhat El-Hadek
Metals 2017, 7(5), 170; https://0-doi-org.brum.beds.ac.uk/10.3390/met7050170 - 12 May 2017
Cited by 2 | Viewed by 5364
Abstract
Iron powders having average particle sizes of ~40 µm are mechanically mixed thoroughly with aluminum powders ranging from 1 to 10 in wt. %, with an average particle size of ~10 µm. Two different powder metallurgy (PM) techniques, cold and hot pressing, are [...] Read more.
Iron powders having average particle sizes of ~40 µm are mechanically mixed thoroughly with aluminum powders ranging from 1 to 10 in wt. %, with an average particle size of ~10 µm. Two different powder metallurgy (PM) techniques, cold and hot pressing, are used to study the effect of the additive element powder on the mechanical properties, wear properties, and the microstructure of the iron based alloys. The hot pressing technique was performed at a temperature reaching up to 500 °C at 445.6 MPa. The cold pressing technique was performed at 909 MPa at room temperature. By increasing the Al content to 10 wt. % in the base Fe-based matrix, the Brinell hardness number was decreased from 780 to 690 and the radial strength from 380 to 228 MPa with reductions of 11.5% and 40%, respectively. Improvement of the wear resistance with the increase addition of the Al powder to the Fe matrix up to five times was achieved, compared to the alloy without Al addition for different wear parameters: wear time and sliding speed. Full article
(This article belongs to the Special Issue Metal Matrix Composites)
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12838 KiB  
Article
Characterization of In-Situ Cu–TiH2–C and Cu–Ti–C Nanocomposites Produced by Mechanical Milling and Spark Plasma Sintering
by Nguyen Thi Hoang Oanh, Nguyen Hoang Viet, Ji-Soon Kim and Alberto Moreira Jorge Junior
Metals 2017, 7(4), 117; https://0-doi-org.brum.beds.ac.uk/10.3390/met7040117 - 29 Mar 2017
Cited by 21 | Viewed by 6245
Abstract
This study focuses on the fabrication and microstructural investigation of Cu–TiH2–C and Cu–Ti–C nanocomposites with different volume fractions (10% and 20%) of TiC. Two mixtures of powders were ball milled for 10 h, consequently consolidated by spark plasma sintering (SPS) at 900 and [...] Read more.
This study focuses on the fabrication and microstructural investigation of Cu–TiH2–C and Cu–Ti–C nanocomposites with different volume fractions (10% and 20%) of TiC. Two mixtures of powders were ball milled for 10 h, consequently consolidated by spark plasma sintering (SPS) at 900 and 1000 °C producing bulk materials with relative densities of 95–97%. The evolution process of TiC formation during sintering process was studied by using X-ray diffraction (XRD), scanning electron microscopy (SEM), and high resolution transmission electron microscopy (HRTEM). XRD patterns of composites present only Cu and TiC phases, no residual Ti phase can be detected. TEM images of composites with (10 vol % TiC) sintered at 900 °C show TiC nanoparticles about 10–30 nm precipitated in copper matrix, most of Ti and C dissolved in the composite matrix. At the higher sintering temperature of 1000 °C, more TiC precipitates from Cu–TiH2–C than those of Cu–Ti–C composite, particle size ranges from 10 to 20 nm. The hardness of both nanocomposites also increased with increasing sintering temperature. The highest hardness values of Cu–TiH2–C and Cu–Ti–C nanocomposites sintered at 1000 °C are 314 and 306 HV, respectively. Full article
(This article belongs to the Special Issue Metal Matrix Composites)
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2796 KiB  
Article
Improved Compressive, Damping and Coefficient of Thermal Expansion Response of Mg–3Al–2.5La Alloy Using Y2O3 Nano Reinforcement
by Amit Kumar, Khin Sandar Tun, Amit Devendra Kohadkar and Manoj Gupta
Metals 2017, 7(3), 104; https://0-doi-org.brum.beds.ac.uk/10.3390/met7030104 - 21 Mar 2017
Cited by 9 | Viewed by 4711
Abstract
In the present study, the effects of the addition of Y2O3 nanoparticles on Mg–3Al–2.5La alloy were investigated. Materials were synthesized using a disintegrated melt deposition technique followed by hot extrusion. The samples were then characterized for microstructure, compression properties, damping [...] Read more.
In the present study, the effects of the addition of Y2O3 nanoparticles on Mg–3Al–2.5La alloy were investigated. Materials were synthesized using a disintegrated melt deposition technique followed by hot extrusion. The samples were then characterized for microstructure, compression properties, damping properties, CTE (coefficient of thermal expansion) and fracture morphology. The grain size of Mg–3Al–2.5La was significantly reduced by the addition of the Y2O3 nano-sized reinforcement (~3.6 μm, 43% of Mg–3Al–2.5La grain size). SEM and X-ray studies revealed that the size of uniformly distributed intermetallic phases, Al 11 La 3 , Al 2 La , and Al 2.12 La 0.88 reduced by the addition of Y2O3 to Mg–3Al–2.5La alloy. The coefficient of thermal expansion (CTE) was slightly improved by the addition of nanoparticles. The results of the damping measurement revealed that the damping capacity of the Mg–3Al–2.5La alloy increased due to the presence of Y2O3. The compression results showed that the addition of Y2O3 to Mg–3Al–2.5La improved the compressive yield strength (from ~141 MPa to ~156 MPa) and the ultimate compressive strength (from ~456 MPa to ~520 MPa), which are superior than those of the Mg–3Al alloy (Compressive Yield Strength, CYS ~154 MPa and Ultimate Compressive Strength, UCS ~481 MPa). The results further revealed that there is no significant effect on the fracture strain value of Mg–3Al–2.5La due to the addition of Y2O3. Full article
(This article belongs to the Special Issue Metal Matrix Composites)
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2488 KiB  
Article
Microstructures and Tensile Properties of Al–Cu Matrix Composites Reinforced with Nano-Sized SiCp Fabricated by Semisolid Stirring Process
by Feng Qiu, Xiang Gao, Jian Tang, Yu-Yang Gao, Shi-Li Shu, Xue Han, Qiang Li and Qi-Chuan Jiang
Metals 2017, 7(2), 49; https://0-doi-org.brum.beds.ac.uk/10.3390/met7020049 - 08 Feb 2017
Cited by 27 | Viewed by 6363
Abstract
The nano-sized SiCp/Al–Cu composites were successfully fabricated by combining semisolid stirring with ball milling technology. Microstructures were examined by an olympus optical microscope (OM), field emission scanning electron microscope (FESEM) and transmission electron microscope (TEM). Tensile properties were studied at room temperature. The [...] Read more.
The nano-sized SiCp/Al–Cu composites were successfully fabricated by combining semisolid stirring with ball milling technology. Microstructures were examined by an olympus optical microscope (OM), field emission scanning electron microscope (FESEM) and transmission electron microscope (TEM). Tensile properties were studied at room temperature. The results show that the α-Al dendrites of the composites were strongly refined, especially in the composite with 3 wt. % nano-sized SiCp, of which the morphology of the α-Al changes from 200 μm dendritic crystal to 90 μm much finer equiaxial grain. The strength and ductility of the composites are improved synchronously with the addition of nano-sized SiCp particles. The as-cast 3 wt. % nano-sized SiCp/Al–Cu composite displays the best tensile properties, i.e., the yield strength, ultimate tensile strength (UTS) and fracture strain increase from 175 MPa, 310 MPa and 4.1% of the as-cast Al–Cu alloy to 220 MPa, 410 MPa and 6.3%, respectively. The significant improvement in the tensile properties of the composites is mainly due to the refinement of the α-Al dendrites, nano-sized SiCp strengthening, and good interface combination between the SiCp and Al–Cu alloys. Full article
(This article belongs to the Special Issue Metal Matrix Composites)
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2113 KiB  
Article
A Meso-Mechanical Constitutive Model of Particle-Reinforced Titanium Matrix Composites at High Temperatures
by Weidong Song, Liansong Dai, Lijun Xiao, Cheng Wang, Xiaonan Mao and Huiping Tang
Metals 2017, 7(1), 15; https://0-doi-org.brum.beds.ac.uk/10.3390/met7010015 - 07 Jan 2017
Cited by 4 | Viewed by 3991
Abstract
The elastoplastic properties of TiC particle-reinforced titanium matrix composites (TiC/TMCs) at high temperatures were examined by quasi-static tensile experiments. The specimens were stretched at 300 °C, 560 °C, and 650 °C, respectively at a strain rate of 0.001/s. scanning electron microscope (SEM) observation [...] Read more.
The elastoplastic properties of TiC particle-reinforced titanium matrix composites (TiC/TMCs) at high temperatures were examined by quasi-static tensile experiments. The specimens were stretched at 300 °C, 560 °C, and 650 °C, respectively at a strain rate of 0.001/s. scanning electron microscope (SEM) observation was carried out to reveal the microstructure of each specimen tested at different temperatures. The mechanical behavior of TiC/TMCs was analyzed by considering interfacial debonding afterwards. Based on Eshelby’s equivalent inclusion theory and Mori-Tanaka’s concept of average stress in the matrix, the stress or strain of the matrix, the particles, and the effective stiffness tensor of the composite were derived under prescribed traction boundary conditions at high temperatures. The plastic strains due to the thermal mismatch between the matrix and the reinforced particles were considered as eigenstrains. The interfacial debonding was calculated by the tensile strength of the particles and debonding probability was described by Weibull distribution. Finally, a meso-mechanical constitutive model was presented to explore the high-temperature elastoplastic properties of the spherical particle-reinforced titanium matrix composites by using a secant modulus method for the interfacial debonding. Full article
(This article belongs to the Special Issue Metal Matrix Composites)
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3421 KiB  
Article
Nano-ZnO Particles’ Effect in Improving the Mechanical Response of Mg-3Al-0.4Ce Alloy
by Sravya Tekumalla, Najib Farhan, Tirumalai S. Srivatsan and Manoj Gupta
Metals 2016, 6(11), 276; https://0-doi-org.brum.beds.ac.uk/10.3390/met6110276 - 11 Nov 2016
Cited by 18 | Viewed by 4489
Abstract
Magnesium based nanocomposites, due to their excellent dimensional stability and mechanical integrity, have a lot of potential to replace the existing commercial Al alloys and steels used in aerospace and automotive applications. Mg-Al alloys are commercially used in the form of AZ (magnesium-aluminum-zinc) [...] Read more.
Magnesium based nanocomposites, due to their excellent dimensional stability and mechanical integrity, have a lot of potential to replace the existing commercial Al alloys and steels used in aerospace and automotive applications. Mg-Al alloys are commercially used in the form of AZ (magnesium-aluminum-zinc) and AM (magnesium-aluminum-manganese) series in automobile components. However, the Mg17Al12 phase in Mg-Al alloys is a low melting phase which results in a poor creep and high temperature performance of the alloys. Rare earth additions modify the phase and hence improve the properties of the materials. In this paper, Ce and nano ZnO particles were added to Mg-Al alloys to attain a favorable effect on their properties. The developed materials exhibited promising properties in terms of thermal expansion coefficient (CTE), hardness, and tensile strength. Further, the ZnO addition refined the microstructure and helped in obtaining a uniform distribution, however without grain size refinement. The increased addition of ZnO and the improvement in the distribution led to an enhancement in the properties, rendering the materials suitable for a wide spectrum of engineering applications. Full article
(This article belongs to the Special Issue Metal Matrix Composites)
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38366 KiB  
Review
Metallurgical Challenges in Carbon Nanotube-Reinforced Metal Matrix Nanocomposites
by Abolfazl Azarniya, Mir Saman Safavi, Saeed Sovizi, Amir Azarniya, Biao Chen, Hamid Reza Madaah Hosseini and Seeram Ramakrishna
Metals 2017, 7(10), 384; https://0-doi-org.brum.beds.ac.uk/10.3390/met7100384 - 22 Sep 2017
Cited by 59 | Viewed by 12378
Abstract
The inclusion of carbon nanotubes (CNTs) into metallic systems has been the main focus of recent literature. The aim behind this approach has been the development of a new property or improvement of an inferior one in CNT-dispersed metal matrix nanocomposites. Although it [...] Read more.
The inclusion of carbon nanotubes (CNTs) into metallic systems has been the main focus of recent literature. The aim behind this approach has been the development of a new property or improvement of an inferior one in CNT-dispersed metal matrix nanocomposites. Although it has opened up new possibilities for promising engineering applications, some practical challenges have restricted the full exploitation of CNTs’ unique characteristics. Non-uniform dispersion of CNTs in the metallic matrix, poor interfacial adhesion at the CNT/metal interface, the unfavorable chemical reaction of CNTs with the matrix, and low compactability are the most significant challenges, requiring more examination. The present paper provides a broad overview of the mentioned challenges, the way they occur, and their adverse influences on the physicomechanical properties of CNT-reinforced metal matrix nanocomposites. The suggested solutions to these issues are fully addressed. Full article
(This article belongs to the Special Issue Metal Matrix Composites)
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