Metal Matrix Nanocomposites Research Articles

In vitro degradation and dry sliding wear behaviour of AZ31-Sn/Al2O3 nano metal matrix composites in simulated body fluid for biomedical application

In this research, tin was added to the AZ31/2Al2O3 magnesium metal matrix composite to investigate its influence on degradation rate in the presence of simulated body fluid (SBF) and wear behaviour in dry conditions. The AZ31- xSn/2Al2O3 ( x = 0, 2, 4, 6, 8, and 10 wt%) composites were manufactured using the bottom pouring stir casting route. The microstructure of the manufactured AZ31/2Al2O3 and AZ31- xSn/2Al2O3 composites revealed that they were composed of the α-Mg solid solution and the intermetallic compound □-Mg17Al12, which was situated near the grain boundaries. When tin was added, the Sn-rich intermetallic compound Mg2Sn was formed, increasing the volume fraction of the Mg2Sn phase. Compared to AZ31/2Al2O3 composite, the wear test revealed that AZ31/2Al2O3 composites containing Sn particles exhibited a higher ability to generate more stable tribo-layers at higher applied loads, which protected the worn surface and reduced the wear rate. The wear resistance of composites was improved primarily by the behaviour of the tribo-layer in the wear process. The degradation rates (mm/year) of the AZ31 composites were carried out for 72 h in SBF. The degradation rate was reduced when the Sn content in the AZ31/2Al2O3 composite was increased to 6 wt% and then increased with further Sn addition. It was observed that when the amount of Sn particles increases up to 6 wt%, the severity of the degradation decreases.

Designing effective plating baths for use in the pulse-reverse plating of copper nanocomposite coatings

ABSTRACT The development of the process to produce Metal Matrix Nanocomposite (MMNC) coatings can provide opportunity for the enhancement of mechanical and electrical properties. This research uses speciation-simulating software to screen formulations for producing nanocomposites by pulse-reverse plating (PRP). PRP is used as a controlled delivery mechanism to attract a high concentration of nanoparticles to the coating during the anodic pulse which are subsequently captured in the cathodic pulse. A disadvantage is that the anodic pulse generates passivating hydroxide layers leading to poor adhesion. Speciation plots assess the stabilising effect of chosen complexants (gluconate and glycine) within electrolytes with the aim of diminishing hydroxide formation. To confirm bath formulation effectiveness before nanoparticle incorporation, UV-Vis spectroscopy and electrodeposition were used. Gluconate and glycine both theoretically produce highly stable complexes and also produce uniform copper deposits supporting the stabilisation effect observed in theoretical studies. This work therefore supports the use of these complexants for future stages of this research.

The effects of different types and ratios of reinforcement, and machining processes on the machinability of Al2024 alloy nanocomposites

In the presented study, aluminum metal matrix nanocomposites reinforced with SiC and B4C, with different reinforcement ratios (0–4 wt%), have been prepared using the powder metallurgy method. The main objective of this study is to investigate the effect of different reinforcements and reinforcement amounts on the machinability of metal matrix nanocomposites using different machining processes (WEDM and CNC milling). The surface morphologies of the samples were investigated before and after machining using scanning electron microscopy and chemical analysis of the samples was obtained using EDX and X-ray diffraction. The surface hardness, roughness, and metal removal rate (MRR) before and after machining were examined to investigate the effect of the machining process on the surfaces of the samples. According to the results of the study, the hardness value of the nanocomposite containing 4% B4C by weight (195.6 HB) increased by approximately 90% compared to the hardness value of the pure Al2024 alloy (101.6 HB). After both machining processes, the hardness values of all nanocomposites decreased. In addition, the tensile strength values of the nanocomposites containing 2% B4C and SiC by weight are 392.8 MPa and 377.7 MPa, respectively, while the tensile strength value of the pure Al2024 alloy is 201.7 MPa. After both machining processes, the hardness values of all nanocomposite samples decreased. While the MRR values decreased with the increase in the reinforcement amount of the nanocomposites after machining, the SR values decreased.

Metal Matrix Alloy AA 6061 Produced by Stir Casting Method

Abstract. In compared to base alloy, aluminum composites made from the AA6061 alloy perform better and have better material properties. The current work provides a thorough analysis of the AA 6061 metal matrix composite (MMC) produced using a traditional stir casting technique. Process parameters and characterization techniques have both been discussed. Upon review, it was found that the most often employed reinforcements for the production of AA 6061 metal matrix nano composite (MMNC) were Al2O3, B4C, SiC, and TiC. Other acceptable reinforcements, such as hybrid, inorganic, nanomaterial, and organic reinforcements, are being considered in the current trend. The AA 6061 hybrid composites have comparable superior qualities to single component composites because they contain two or more reinforcements. There is a tonne of room for AA study. Research on the AA 6061 nanocomposite, which has significantly higher strength and wear resistance and is suitable for aerospace and defence applications, has a lot of potential.

An Investigation on the Enhanced Wear Behavior of Ultrasonically Stirred Cast A356/SiO2np Nano-composites

Metal matrix nanocomposites (MMNCs) are becoming the materials of choice in a variety of engineering and medical applications owing to their exhibiting a superior combination of targeted properties. Amongst different MMNCs, aluminum-based composites are of special importance. In many applications, a relatively inferior wear property limits the use of this valued metal in practice. However, reinforcing aluminum and its alloys by ceramics, carbon allotropes, etc., may circumvent these limitations to a great extent. In the present study, aluminum alloy A356/SiO2 nanocomposite is fabricated by a vibration-assisted casting process, wherein varied amount of nanosilica, namely, 0.125, 0.25, and 0.375 wt.%, have been added to the melt. The use of power ultrasonic treatment had a great influence on the microstructure, hardness, and wear properties. Microstructural and XRD analyses were performed on the fabricated monolithic and composite samples. To evaluate wear behavior, a hardness test and pin-on-disk experiment were conducted on the samples under 60, 80, and 100 N forces at a constant speed of 1 m/s and the sliding distance was varied from 1000 to 2000 m. The abraded surfaces, wear debris, and EDS analysis were used to identify wear mechanisms. The samples having 0.125 wt.% exhibited the highest increase in hardness and the highest reduction in both friction coefficient and wear rate by 52%, 50%, and 68%, respectively. The main governing wear mechanism was abrasion, with limited evidence of delamination.

Additive manufacturing of metal matrix nanocomposites: Novel approach for nanoparticles dispersion by electromagnetic three-dimensional vibration

A novel electromagnetic three-dimensional vibration approach was employed for powder feedstock preparation oriented to additive manufacturing of metal matrix nano-composites (MMNCs). The efficiency of this promising mixing technique was validated by laser powder bed fusion (LPBF) of AlSi10Mg reinforced with 3 wt% of B4C nanopowder. Scanning electron microscopy (SEM) analysis revealed that a uniform dispersion of B4C was achieved on the AlSi10Mg powder surface, while retaining its original spherical morphology. The modified powder recycling had no influence on the adherence of nanoparticles to the powder surface. The LPBF-processed samples exhibited good homogeneity in the nano B4C distribution, resulting in an increase in hardness compared to unmodified AlSi10Mg. This high-productivity and cost-efficient approach provides a remedy for the process chain bottleneck in the additive manufacturing of MMNC.

Microstructural Characterization of Al/CNTs Nanocomposites after Cold Rolling.

The deformation behaviour of aluminium reinforced by carbon nanotubes (Al/CNTs) nanocomposites during cold rolling was investigated in this work. Deformation processes after production by conventional powder metallurgy routes may be an efficient approach to improve the microstructure and mechanical properties by decreasing the porosity. Metal matrix nanocomposites have enormous potential to produce advanced components, mainly in the mobility industry, with powder metallurgy being one of the most reported production processes. For this reason, it is increasingly important to study the deformation behaviour of nanocomposites. In this context, nanocomposites were produced via powder metallurgy. Advanced characterization techniques carried out the microstructural characterization of the as-received powders and produced nanocomposites. The microstructural characterization of the as-received powders and produced nanocomposites was carried out through optical microscopy (OM), and scanning and transmission electron microscopy (SEM and TEM), complemented by electron backscattered diffraction (EBSD). The powder metallurgy route followed by cold rolling is reliable for Al/CNTs nanocomposites. The microstructural characterization shows that the nanocomposites exhibit a different crystallographic orientation than the Al matrix. CNTs in the matrix influence grain rotation during sintering and deformation. Mechanical characterization revealed that during deformation, there is an initial decrease in the hardness and tensile strength for the Al/CNTs and Al matrix. The initial decrease was attributed to the Bauschinger effect being more significant for the nanocomposites. The difference in the mechanical properties of the nanocomposites and Al matrix was attributed to distinct texture evolution during cold rolling.

Gaussian filtering method of evaluating the elastic/elasto-plastic properties of sintered nanocomposites with quasi-continuous volume distribution

In this work, combing the Gaussian filtering algorithm and the cutting quantile functions, a new technique is developed to efficiently generate the RVE of randomly distributed metal matrix nanocomposites (MMNCs) with quasi-continuous volume distribution. The procedures of filtering the random point matrix, generating the random field, separating the spatial points into constituents, and imposing the periodic boundary conditions are numerically implemented in detail. By contrasting the elastic/elasto-plastic properties of the sintered AgNPs composites with those determined by experimental measurements and analytical models, the proposed numerical homogenization model is verified. The results show that the proposed algorithm can control the distributions of the reinforcement size and the matrix volume fractions by tailoring the Gaussian widths and cutting levels. Meanwhile, the ratio of the Gaussian widths to the RVE length σ/L make influences on the resulting elastic/elasto-plastic properties of the MMNCs, and for the sintered AgNPs composites, σ/L = 2.5 is the critical value of its convergence. Additionally, the proposed method can be also extended to predict the other physical properties of MMNCs including conduction and diffusion.

Analysis of mechanical properties enhancement on composites of AA7175 by multi walled carbon nano tube (MWCNT)

Developed to meet the demands of appealing contemporary materials, nanocomposites are polyphase materials that include a matrix and nano-reinforcement. The major types of nanocomposites are as follows. They are categorized as fiber-reinforced nanocomposites, laminar nanocomposites, and particulate nanocomposites based on the reinforcing component, whereas they are classed as metal matrix, ceramic matrix, and polymer matrix nanocomposites based on the matrix ingredient. Due to its advantages over polymer and ceramic matrix, metal matrix nanocomposites (MMNCs) are the most common type of nanocomposites employed in industrial applications. To improve the physical, mechanical, thermal, and electrical properties of conventional materials, nanocomposites are often formed by reinforcing nanoscale tubes, fibres, particles, or sheets. To keep up with technological advancements, drive market changes, and bridge technological gaps by revolutionizing the product, innovative nanocomposites must be used in advanced engineering applications. The high-strength, light-weight aluminium alloy matrix nanocomposites (AMNCs) are able to replace traditional materials to a greater extent in cutting-edge applications including the automotive, aircraft, marine, defense, leisure, and electronic industries. In this study deals with the property enhancement analysis by means of the assistance of Multi Walled Carbon nano tube (MWCNT) nano particles encouragement in AA7175 aluminium alloy. The main focus of this investigation on the tensile related mechanical properties such as tensile strength, percentage of elongation and yield strength. The composites were created with the mass fractions of 5.0 wt%, 4.0 wt%, 3.0 wt%, 2.0 wt% and 1.0 wt% of MWCNT with 95.0 wt%, 96.0 wt%, 97.0 wt%, 98.0 wt% and 99.0 wt% of AA7175 aluminium alloy. These composite mechanical properties were compared with the pure AA7175 aluminium alloy. Among the comparison of these composites values 3.0 wt% of MWCNT produce the greater results on the considered composites. The composite sample recorded high Ultimate Tensile Strength of 431.12 MPa, low Percentage of elongation of 9.58% and high Yield strength of 396.63 MPa.

Metal Matrix Nanocomposites: A Brief Overview

Abstract: The need for lightweight materials is increasing at a faster rate in the engineering field. It demands materials with high strength, low weight, and properties like ductility and formability which are required for easier processing of the material. When conventional pure metals and alloys failed to meet this demand, many researchers turned their attention toward developing composites. Composites can be fabricated from metal, polymer, and ceramic as base materials which are known as metal matrix composites (MMC), polymer matrix composites (PMC), and ceramic matrix composites (CMC), MMC are of special importance due to properties like strength, stiffness, and formability which are difficult to obtain from PMC and CMC. Even though conventional composites with micron-size reinforcement have enhanced certain properties like strength, hardness, and wear resistance, it deteriorated other desirable properties like ductility. To overcome these limitations of micro-composites, a new category of materials known as nanocomposite has been developed. Nano composites are materials that contain nano-scale reinforcement in different forms. This review article summarizes the recent progress in the field of metal matrix Nano composite (MMNC). Methods of fabrication which are applicable for metal alloys and micro- composites are mostly not suitable for nanocomposite fabrication, the recently developed fabrication process which are applicable for MMNC’s are discussed in this article. The effects of added nano reinforcement on the microstructure are also discussed with suitable examples. Enhancements in mechanical, tribological, and physical properties are explained in depth with the help of recently published data. Strengthening mechanisms are described with the help of empirical relations. Although industrial applications of metal matrix nano composites are limited due to the ongoing developments in this field, a few important potential application areas are also discussed at the end of this article.

Fabrication and investigation on mechanical properties of heat treated Al6061 nano metal matrix composites reinforced with ZrB2

A progress has been put to evaluate the various composite combinations and how they impact the characteristics of the various aluminum alloys. In order to conduct an overall investigation of the composites, a full understanding of the characteristics is offered, and the best findings may be used for the continued development of the Aluminum reinforced composition. The mechanical characteristics and microstructure of an Al6061 alloy reinforced by nanoscale zirconium diboride (ZrB2) particles were evaluated in the presentwork. The development of Al6061 metal matrix nanocomposites (AMMNCs) via the stir casting technique is employed by altering the amount of ZrB2 nanoparticles from 0 to 2 wt%, X-ray Diffraction (XRD) was employed. Analysis using a scanning electron microscope (SEM) exhibit that ZrB2 nanoparticles are uniformly distributed throughout AMMNCs. The inclusion of ZrB2 nano particles improved the AMMNCs' functionality. ultimate yield strength, hardness, and tensile strength respectively. The results suggest that increasing the weight percentage of reinforcement in the produced nanocomposite improves mechanical characteristics.

Production of Al2024/h-BN nanocomposites with improved corrosion, wear and mechanical properties

In this study, hexagonal boron nitride (h-BN) reinforced Al-based metal matrix nanocomposites were successfully prepared using a powder metallurgy-assisted high-energy ball milling and vacuum-hot pressing process. Al2024 alloy and h-BN nano-powders (at 0, 2, 3, 4, and 5wt%) were milled for 8 h to produce Al2024/h-BN nanocomposites. The effect of h-BN nanoparticle content on the microstructure, density, hardness, tensile strength, wear, and corrosion behavior of Al2024/h-BN nanocomposites was investigated. It was observed that the h-BN powders in the Al2024/h-BN nanocomposites were homogeneously distributed up to a content of 4 wt%, beyond which the h-BN aggregated at the grain boundaries due to excessive reinforcement. The uniform distribution of h-BN nanoparticles in the Al2024 matrix had a positive effect on the mechanical properties and wear and corrosion behavior of the Al2024/h-BN nanocomposites. The results showed that the highest values of hardness and tensile strength were 126 HB and 299.72 MPa, respectively, in the 4 wt% h-BN reinforced sample. The wear volume loss decreased significantly as the h-BN reinforcement content increased up to 4 wt %. The corrosion experiment results showed that the corrosion resistance of the 4 wt % h-BN reinforced nanocomposite, which had the lowest polarization resistance of 15.22 Ω cm2, was almost 5 times higher than that of the unreinforced Al2024 alloy.

Strengthening behaviour of forged in-situ developed magnesium composites

ABSTRACT Mg alloys/composites can fulfil evolving needs of the automotive industry. Mg-based in-situ developed metal matrix nano-composites (MMnCs) are not researched well. In the present study, Mg-based hybrid MMnCs have been developed by in-situ reinforcement of MgO and CeO2 particles through the stir casting process. The minimum reinforcement size has been confirmed as 20 nm during transmission electron microscopy (TEM). MMnCs were subjected to high-temperature press forging. Thus,significantly reducing porosity. The evolved texture, mechanical properties were evaluated near the central and peripheral regions of the forged disk. Fractography was carried out to confirm the nature of the fracture. The Central region of disk showed better mechanical properties than peripheral region. The dominant presence of basal texture near the peripheral area led to tensile twinning and, thus, prominent strain hardening during compression. Further, strengthening mechanisms were used to predict the yield strength. It is found that Taylor’s strengthening is the dominant strengthening mechanism.

Effect of Vacancy Defect Content on the Interdiffusion of Cubic and Hexagonal SiC/Al Interfaces: A Molecular Dynamics Study.

The mechanical properties of ceramic-metal nanocomposites are greatly affected by the equivalent properties of the interface of materials. In this study, the effect of vacancy in SiC on the interdiffusion of SiC/Al interfaces is investigated using the molecular dynamics method. The SiC reinforcements exist in the whisker and particulate forms. To this end, cubic and hexagonal SiC lattice polytypes with the Si- and C-terminated interfaces with Al are considered as two samples of metal matrix nanocomposites. The average main and cross-interdiffusion coefficients are determined using a single diffusion couple for each system. The interdiffusion coefficients of the defective SiC/Al are compared with the defect-free SiC/Al system. The effects of temperature, annealing time, and vacancy on the self- and interdiffusion coefficients are investigated. It is found that the interdiffusion of Al in SiC increases with the increase in temperature, annealing time, and vacancy.

Enhanced distribution and mechanical properties of high content nanoparticles reinforced metal matrix composite prepared by flake dispersion

Achieving a uniform dispersion and high efficiency in metal matrix nanocomposites (MMNCs) with a high-content of nano-reinforcements is still a challenging issue. Flake dispersion, a fabrication process combining flake powder metallurgy with high-shear dispersion, is proposed to alleviate the problem. In this regard, flake Al powders with a large specific surface-area were used as a core to be coated with a high content of SiC nanoparticles through the well-established high-shear dispersion process. The produced SiCnp/Al nanocomposites, reinforced with 5 wt% and 10 wt% SiCnp, showed a uniform distribution of intragranular nanoparticles within an ultrafine-grained matrix. Furthermore, the 10 wt% SiCnp/Al nanocomposite exhibited a yield strength of 306 MPa and an ultimate tensile strength of 420 MPa, which were, respectively, 191% and 202% higher than the unreinforced matrix. Meanwhile, the composite maintained an acceptable fracture elongation (up to 10.8%) which can be attributed to the homogeneous and intragranular distribution of nanoparticles in the matrix. The results authenticated that flake dispersion is an efficient strategy to derive synergistic effects contributing to simultaneously enhancing strength and ductility in MMNCs.

A review on mechanical properties of aluminium-based metal matrix nanocomposites

Industrial production today requires new improved materials to meet market demands, which leads to the production of new materials with improved properties. One kind of response to those requirements is the development of metal matrix composites (MMCs) with the aim of obtaining materials with better properties when compared to conventional metals and alloys. Nowadays, metal matrix nanocomposites (MMnCs) are being increasingly investigated due to the possibility of achieving better machinability, high fracture toughness and improved ductility when compared to conventional composites. Considering the pace of development and the huge perspective of different classes of materials, this research aims to provide insight into the mechanical properties of aluminium nanocomposites. Aluminium nanocomposites are attracting a lot of attention due to their high strength-to-weight ratio, wear resistance and low costs, when compared to matrix alloy. In this paper, an attempt is made to review other research reports and make a connection between the characteristics of the microstructure and the mechanical properties, which are dependent on the method of fabrication and type and content of reinforcement.

Experimental investigation on the effet of input paramètres on surface roughness and MRR of abrasive flow machining process

A crucial and costly step in the whole manufacturing process is the precision and super finishing procedure. A step of final finishing is involved in the production of precision components. It accounts for a respectable portion of the cost of production overall, is mostly uncontrolled, and requires a lot of manpower. Abrasive finish methods are being developed to address issues including high direct costs and the production of precision components with particular characteristics for finishing inaccessible places. A vast number of cutting blades with arbitrary orientation and shape are used in the abrasive finishing process. Due to their ability to complete a variety of form geometries with the appropriate dimensional accuracy and surface polish, abrasive fine procedures are often used. The unconventional finishing method known as AFM (abrasive flow machining) presses abrasive viscoelastic polymer on the surface of work piece. Al7075/SiC NMMCs’ internal rounded and hollow surfaces are completed using an AFM trial procedure that is constructed and designed in conjunction with specially produced medium. Workpieces are created using a lathe shortly after stir casting metal matrix nano composites with cross sections of 25 mm in diameter and containing 1 percent,1 ,2,3,4 nano-Sic (50 nm) by weight. Extrusion pressure abrasive particle grain size number of cycles were evaluated for their surface roughness (Ra) than material removal (MR), respectively. The evaluation of the material’s qualities, such as density, hardness, and tensile strength The improvement in the surface completeness of these NMMCs is further shown by the scanning Microscopy OM, EDS SEM, and XED analyses.

An overview of recent developments in Al metal matrix nanocomposites for strength-ductility synergy

Researchers worldwide switched their attention from homogeneous structures to heterogeneous structures because they needed composite materials that possess both ultra-high strength and ductility. The goal is to improve the mechanical properties of composite materials by making a new “Harmonic Structure” (H.S.) with a controlled bimodal grain size distribution. A powder metallurgy-based fabrication method has been developed to achieve a controlled microstructure, including a mechanical or a bi-model milling process. Consolidated mechanical milled or bi-model milled powder has been sintered to get the final harmonic structure. The harmonic structure-designed metallic materials are solid and ductile simultaneously because of the microstructure matrix's optimized hierarchical features, which create strain delocalization during plastic deformation. So, unlike traditional homogeneous (homo)-structured materials, HS-designed materials can have synergy effects like synergy strengthening. This study shows how tailoring strain delocalization has changed the strength-ductility synergy. In addition, this study supports future innovations toward a balance between high strength and high ductility.

Additive Manufacturing of Metal Matrix Nanocomposites: Novel Approach for Nanoparticles Dispersion by Electromagnetic Three-Dimensional Vibration

Additive Manufacturing of Metal Matrix Nanocomposites: Novel Approach for Nanoparticles Dispersion by Electromagnetic Three-Dimensional Vibration

Optimization of process variables on Electrical Discharge Machining of novel Al7010/B4C/BN hybrid metal matrix nanocomposite

In this paper, determination of optimum EDM input variables like discharge current (DC), pulse on time (Pon), pulse off time (Poff), and gap voltage (GV) on responses like material removal rate (MRR) and surface roughness (SR) using Taguchi technique on the novel Al7010/2%B4C/2%BN hybrid metal matrix nanocomposite (HMMNC) manufactured through ultrasonic assisted stir casting (UASC) route. The various experiments were planned and carried out L16 orthogonal array and regression equations were established by using Analysis of variance (ANOVA) to examine the impact of pulse factors. The outcomes exposed that discharge current greatest effect factor on MRR and SR was found with % contribution of 82.07% and 86.86%. It is also identified that the optimum level conditions of pulse factors for MRR and SR is A4B4C1D1 and A1B1C4D4. The outcomes were further determined by utilizing confirmatory experiment. The machined surface morphology was observed through Scanning electron microscope (SEM).