Metal Matrix Nanocomposites Research Articles

Mechanical Characterization by Multiscale Indentation of Particle Reinforced Nickel-Alumina Metal Matrix Nanocomposites Obtained by High-Kinetic Processing of Ball Milling and Spark Plasma Sintering

Mechanical Characterization by Multiscale Indentation of Particle Reinforced Nickel-Alumina Metal Matrix Nanocomposites Obtained by High-Kinetic Processing of Ball Milling and Spark Plasma Sintering

Modeling of Dry Conditioned Sliding Wear And Friction Behavior of Heat-Treated Silicon Nitride Strengthened Al Metal Matrix Nanocomposites

In the presented work, the sliding wear under dry conditions and friction behaviour of Si3N4 reinforced high-strength Aluminum alloy (AA)7068 nanocomposites have been investigated under various loads, sliding velocity, and rubbing distances. The fabrication of nanocomposites has been done by using the stir casting technique with the advancement of ultrasonication. Scanning electron microscope (SEM), Elemental mapping, and energy dispersive spectroscopy (EDS) are used to analyze the microstructure of prepared nanocomposites and worn surfaces. The wear resistance improves with the incorporation of Si3N4 particles in Al 7068 alloy and further increases by increasing the weight % of reinforcement. The reinforcement is done by 0.5, 1, and 1.5 % Si3N4 by weight. ANOVA reveals that sliding distance is the most dominating factor in the wear loss of samples, and load became the most influential parameter in the coefficient of friction (COF). Microstructure reveals grain boundaries become discontinued after T6 heat treatment. AMNCs containing 1.5wt.% Si3N4 shows minimum wear loss compared to other nanocomposites and alloys.

Microstructure evolution, mechanical properties, and fractography of AA7068/ Si3N4 nanocomposite fabricated thorough ultrasonic-assisted stir casting advanced with bottom pouring technique

Ceramic particulate embedded aluminum metal matrix nanocomposites (AMNCs) possess superior mechanical and surface properties and lightweight features. AMNCs are a suitable replacement of traditional material, i.e., steel, to make automotive parts. The current work deals with developing Si3N4 strengthened high strength AA7068 nanocomposites via novel ultrasonic-assisted stir casting method advanced with bottom pouring setup in the proportion of 0.5, 1.0, 1.5, and 2 wt.%. Planetary ball milling was performed on a mixture of AA7068 powder and Si3N4 (in the proportion of 3:1) before incorporation in aluminum alloy melt to avoid rejection of fine particles. Finite element scanning electron microscope (FESEM), Energy dispersive spectroscopy (EDS), X-Ray diffraction (XRD), and Elemental mapping techniques were used in the microstructural investigation. Significant grain refinement was observed with increasing reinforcing content, whereas agglomeration was found at higher weight %. Hardness, Tensile strength, ductility, porosity content, compressive strength, and impact energy were also examined of pure alloy and each composite. Improvement of 72.71%, 50.07%, and 27.41 % was noticed in hardness value, tensile strength, and compressive strength, respectively, at 1.5 weight % compared to base alloy because of various strengthening mechanisms. These properties are decreased at 2 wt.% due to severe agglomeration. In contrast, nanocomposite’s ductility and impact strength continuously decrease compared to monolithic AA7068. Fracture analysis shows the ductile and mixed failure mode in alloy and nanocomposites.

Enhancing wear properties of Al6061 metal-matrix composites by reinforcement of ZrB2 nano particles

The present study investigated the wear behaviour of Al6061 alloy reinforced with nano zirconium diboride (ZrB2) particles. The Al6061 metal matrix nanocomposites (AMMNCs) werefabricated by the addition of ZrB2 nanoparticles in various wt.% using stir casting route. Microstructure and XRD analysis was carried out on Al6061 alloy and fabricated composites. The wear and friction behaviour of AMMNCs were analyzed using a pin on disctribometer with varying loads of 10, 20 and 30 N. The lower wear rate of 0.0044 mm3/m was observed for AMMNCs with 2 wt% of ZrB2. The results show that the developed nanocomposites enhanced the wear properties of Al6061 alloy with an increased wt.% of ZrB2 reinforcement.

Effect on abrasive water jet machining of aluminum alloy 7475 composites reinforced with CNT particles

Using Taguchi's experimental design, which takes pressure, abrasive feed rate, and stand-off distance into account, this study examines mechanical properties of a novel carbon nanotube-reinforced aluminium metal matrix nanocomposites (AMMNC). It also examines machinability of the resulting nano composite. Optimization of outputs such as material removal rate and average roughness (Ra) is done using the TOPSIS method. Reinforcement of the aluminium alloy AA7475 (AA7475) with CNT is achieved by using different CNT weight fractions (3%, 6%, 9%) in the fabrication of AMMNC. ASTM procedures are used to evaluate mechanical properties such as tensile and compressive strength and hardness. When compared to as-cast AA7475, materials with a higher concentration of CNT have higher tensile strength (22.14%), compressive strength (29.01%), hardness (21.49%), wear resistance (64.51%), and corrosion resistance (98.6%). According to machining studies, when CNT is increased to 9 percent, the SR and MRR increase as well as abrasive flow rate, which necessitates an increase in abrasive flow rate to remove material from the composite.

Analysis and Experimental Investigation of A356 Aluminium Alloy Hybrid Composites Reinforced with Gr‐FE3O4‐B4C Nanoparticles Synthesised by Selective Laser Melting (SLM)

Additive manufacturing techniques (AMTs) evolved quickly from simple prototype options to promising additive manufacturing techniques. The additive technologies, which include point‐by‐point material merging, full melting, and solidification of powder particles, provide potential unique braves and advantages with nanometal powders. In the fabrication of A356 aluminium alloy‐based hybrid metal matrix nanocomposites, graphite (Gr), iron oxide (Fe3O4), and boron carbide (B4C) are used as nanoreinforcement. Famous AMTs like selective laser melting have created A356 hybrid nanocomposites (SLM). The ingot was made out of a cylindrical slot measuring 14 × 100 mm. The percentages 2%, 4%, and 6% are added to the reinforcements Gr, Fe3O4, and B4C. Microtensile and microhardness tests were used to determine the outcome of the reinforcement. Microtensile and microhardness parameters are assessed using microtensile test equipment and a Vickers hardness tester, with the specimen prepared in accordance with ASTM standards. A356 with 2, 4, and 6% reinforcing has a Vickers Hardness Number (VHN) of 144, 163, and 188, respectively. As the boron carbide reinforcement is increased, the load value of graphite and iron oxide (2, 4, and 6%) rises. The greatest ultimate tensile strengths are 260.10, 290.06, and 325.43 N/mm2, respectively. The bonding structure of nanocomposites is assessed using an OM, and then, microtensile specimens are assessed using a SEM. As a result of the superior effect of the diverse reinforcements Gr, Fe3O4, and B4C, more increased tensile and hardness qualities have been attained.

Machine learning assisted prediction of mechanical properties of graphene/aluminium nanocomposite based on molecular dynamics simulation

Predicting mechanical properties of graphene-reinforced metal matrix nanocomposites (GRMMNCs) usually requires atomistic simulations that are computationally expensive without scalability or micromechanics-based models (such as widely used Halpin-Tsai model) that may lead to considerable errors in many cases. This paper first combines molecular dynamic (MD) simulation and machine learning (ML) techniques to predict the mechanical properties of graphene reinforced aluminium (Gr/Al) nanocomposites and use them to modify Halpin-Tsai model. Extensive MD results for Young’s modulus and ultimate tensile strength of Gr/Al nanocomposites are obtained, with the intricate effects of graphene’s volume fraction, alignment angle, chirality and environment temperature being taken into account. After training and optimization based on MD data, ML models are developed with the capability in estimating Young’s modulus and ultimate tensile strength. The micromechanics based Halpin-Tsai model is then modified by using the Young’s modulus predicted by both MD and ML models such that the Young’s modulus can be readily determined with significantly improved accuracy from an explicit relationship that is very easy to use in the analysis and engineering design of Gr/Al nanocomposite structures.

Surface morphology and microstructural analysis of al 8081-mg/zr/tio2 nano metal matrix composite – A base for performance evaluation of polycrystalline diamond and poly cubic boron nitride tools

The investigation of surface roughness in machined materials/products has proven to be a difficult undertaking. The surface quality is determined not only by the parameters but also by the cutting conditions. Surprisingly, a study indicated that when analysing the quality of machining processes currently being done, surface morphology has a significant impact on tool performance. PCD (Polycrystalline diamond) and PCBN (Poly cubic boron nitride) cutting tools produce a better surface finish, which is explored in the machining of Al-Mg/Zr/TiO2 (15%), nano metal matrix composites (NMMC). The study primarily focuses on determining the best parameters for end milling NMMCs in tests for long-term production sustainability. Using scanning electron microscopy, microstructural study of the machined surface will aid in finding the parameters responsible for the cause of surface integrity. The work focusses on analysing tool performance by monitoring the machining process in real time using signal characteristics, forecasting vibrations (displacement) and machine outputs using surface topography and chip analysis. The tool failure was acquired by establishing a correlation between displacement (vibrations) and post machining outcome of experimental study, as a result, the evolution of displacement in the PCBN tool is 24.7 μm, which is better compared to 34.3 μm in the PCD tool at 3000 r/min. PCBN outperformed PCD with a 1.82 μm surface roughness, resulting in longer tool life. Thus, this economical reliable empirical method the problem of finding difficulty identifying the causing of tool wear and failure by correlating sensor signals features with experimental results.

Ultrasonically Stir Cast SiO2/A356 Metal Matrix Nanocomposites

Metal matrix nanocomposites are a newly developed materials with promising applications in a wide variety of areas, ranging from medical to aerospace structures, owing to their lightweight high-strength properties. A light metal like aluminum is usually strengthened by a reinforcing agent of carbides, nitrides, oxides, carbon-based materials, or even elementals to boost the mechanical performance without sacrificing lightweight; however, almost all reinforcing nanomaterials are commonly poorly wetted by metals leading to agglomerations, clusterings, among other problems, with diminished ductility and overall mechanical performance. To tackle the mentioned problems, a number of strategies including coatings, thermal, mechanical, or chemical treatments may be followed. In the present study, a particular focus is paid on the mechanical dispersion of nano-silica particles in a molten A356 alloy through applying high-intensity ultrasonic agitations in order to improve dispersibility, wettability, and interfacial affinity. Nano-silica being an inexpensive high-strength nanomaterial is added to an A356 aluminum alloy melt and then dispersed and distributed by a 2-kW power ultrasonic system. Experimental results including microscopic observations and those mechanical experimentations revealed that the ultrasonication of the aforesaid solid–liquid system may greatly improve the affinity between the de-agglomerated nano-silica particles and the host aluminum matrix with enhanced ductility.

Microstructure and mechanical behavior of Al6061/Ni/Cr hybrid nano metal matrix composites with addition of graphene and magnesium

The present work emphasizes the micro structural and mechanical behavior of Al6061 hybrid nano-metal matrix composite (HNMMCs) reinforced with variable wt% (0, 0.6, and 1.2) of nickel and chromium nanoparticles with a fixed amount of 0.6 wt% of graphene and 0.5 wt% Magnesium oxide nano particles. The advanced stir-casting route fabricates the HNMMCs. Tensile and micro hardness tests as per ASTM standards were conducted to analyze the mechanical behavior of samples of advanced composites. The micro structural behavior of advanced composites was investigated by the field emission scanning electron microscope (FESEM). The SEM micrographs and energy dispersive spectroscopy (EDS) mapping analyses confirmed the uniform distribution and presence of reinforced particles within the Al6061 matrix. The study of this work revealed significant improvement in tensile strength and microhardness of developed composite with respect to Al6061.

Corrosion, optimization and surface analysis of Fe-Al2O3-CeO2 metal matrix nanocomposites

In the present work, metal matrix nanocomposites are being prepared using Fe as base material reinforced with Al2O3 and doped with CeO2. Nanocomposite specimens were synthesized using powder metallurgy technique. Tafel Polarization, Corrosion Behavior and its optimization using Analysis of Variance (ANOVA) as well as Technique for Order of Preference by Similarity to Ideal Solution (TOPSIS) along with Phase and Microstructure of prepared samples have been investigated. It was observed that corrosion rate and corrosion current density was highest for pure Fe samples whereas 1.0% CeO2 doped Fe-Al2O3 metal matrix nanocomposite system showed the formation of nano amorphous layer on the specimen surface. Analysis of Variance shows that the different compositions of samples have changed outcome on corrosion behavior. Technique for Order of Preference by Similarity to Ideal Solution analysis shows ordered preference of sample as per the readings of corrosion rate.

Metallurgical, mechanical and tribological behavior of Reinforced magnesium-based composite developed Via Friction stir processing

Reinforced magnesium metal matrix nanocomposites (MMMNCs) have piqued the interest of scientific community in recent years. Friction stir processing (FSP) is a known process to achieve the highest level of secondary phase nanocomposites distribution in the base monolithic matrix. In this study, an attempt has been made to synthesize magnesium base AZ61A/n-TiC nanocomposites using FSP and the influence of tool rotational speed on the metallurgical, mechanical, and tribological behavior of the developed composites has been studied. Microstructural examination shows that as tool rotational speed increases, high plastic deformation occurs and heat is generated along with the concomitant shattering impact of rotation, which consequently develops larger grains in the stir zone. However, this also provides thrusts resulting in uniform distribution of the nanoparticles in the base matrix. Microhardness and ultimate tensile strength of the developed nanocomposite were found to be significantly improved when contrasted with the base metal. Lower wear rate was observed for the composite developed at 800 rpm along with the abrasive type of wear mechanism.

The investigation of the effect of nano particles on dry sliding wear and corrosion behavior of Al-Mg/Al2O3 composites

Aluminum matrix composites were extensively used as structural material as it possesses good surface properties such as wear and corrosion resistance. The practical importance of nano particles in composite materials has triggered widespread attention towards the enhancement of its properties. In this study, Al-Mg/Al2O3 (0–8 wt%) metal matrix nano composites fabricated by two step stir casting route was investigated to comprehend its wear and corrosion behaviour. The Pin-on-Disc dry sliding wear test was performed on Al-Mg/Al2O3 (0–8 wt%) by adopting Design of Experiments under the action of different contact loads and sliding distance following the ASTM G99 Standard. The experimental results conveyed that specific wear rate decreases with increase in sliding distance. Statistical analysis was performed by Taguchi’s Technique and Analysis of Variance (ANOVA) to determine the most dominating factor that influences specific wear rate for the optimum weight percentage of reinforcement. Analysis revealed adequacy with the constructed model in predicting the wear behavior of composite and unreinforced Al-Mg alloy. The corrosion behaviour of the base alloy and composites was analysed by static immersion and electrochemical assessments, by immersing prepared specimens in aqueous sodium chloride (3.5%) solution. The dependance of corrosion rate of the composites with the weight percentage of Al2O3, exposure duration and temperature of the corrosive medium was studied in detail. Corrosion test results exhibit that corrosion rate decreases with increase in weight percentage of Al2O3 particles and exposure duration, whereas it follows reverse trend with increase in corrosion medium temperature.

Processing, and Characterization of AZ91D Magnesium Alloy Reinforced Nano TiC, B4C, and HBN Composites

This paper presents the development of AZ91D Magnesium Alloy metal matrix composites having optimum mechanical and tribological properties by adding a various in-organic Nano reinforcements such as Titanium Carbide (TiC), Boron Carbide (B4C) and Hexa Boron Nitride (HBN). The processing techniques and characteristics of AZ91D Magnesium Alloy metal matrix nanocomposites and their application developed a new era in the material science, engineering and other related technologies has been discussed and how AZ91D Magnesium Alloy metal matrix with TiC, B4C, and HBN Nano particles have proven plat form and contribute to make a in depth engineering research.

Modeling and optimization of the control parameters in machining of aluminum metal matrix nanocomposite under CNT induced nanofluid

Mechanical fastening is crucial in the aviation industry as it allows huge composite assemblies to be made. Although several researches have examined the turning operation of metal matrix composite (MMC), very few have examined the optimization of turning on nano MMCs using Carbon Nanotube based nanofluid. This is because the specified materials are relatively new to the commercial industries. As hybrid nanocomposites have different characteristics than typical MMC, they will perform differently when mechanically turned. In this study, the turning of the Aluminum Nano MMC in a dry and wet environment (reinforced with Carbon Nanotube) were investigated and the surface roughness was measured as the response variable. The optimization of the control parameters was carried out applying Taguchi orthogonal array design and it was found that in wet environment-induced with nanofluid higher cutting speeds and lower feed rates with SNMG carbide insert improved the surface quality to a large extent.

A review on - fabrication and testing methods of aluminium metal matrix nano composites for various applications

Nowadays the use of Aluminium-based Nanocomposites is increased in aerospace, automotive and marine industries. Aluminium Metal Matrix Nano Composites (AMMNCs) have an excellent combination of mechanical and physical properties such as stiffness, strength, hardness, lightweight and high thermal resistance as compared to the conventional materials. Nano reinforcements like SiC, Al2O3, AlC, B4C, CNT, Ni, Ti etc., can be mixed in aluminium in the form of particles or whiskers. The grain-reinforced composite material has better plastic forming ability than the whisker or fiber reinforced composite material. According to several works of literature, the mechanical properties of AMMNCs are greatly influenced by the parameters like reinforcement material, grain size and percentage of reinforcement. It is believed that the materials choice, microstructural highlights, assembling and handling boundaries, and so on affect the weariness reaction of MMNCs.

Numerical validation of thermal conductivity of Al6061 based hybrid nano metal matrix composite filled with nanoparticles of Ni and Cr

Aluminum composite matrix materials are regarded as the most popular type of composite materials. Metal matrix composites made of aluminum have better mechanical and thermal properties, including a higher strength-to-weight ratio, tensile strength, hardness, and a low coefficient of thermal expansion. In various types of applications viz, automobile, aviation, the thermal characterization of aluminum metal matrix composites has increased. Thermal conductivity as a function of temperature, thermal diffusivity, and the thermal gradient is one of the essential thermal characteristics of aluminum metal matrix composites needed to understand the material’s behavior. The current work evaluated thermal conductivity as a product of thermal diffusivity, density, and specific heat for Al6061/Ni/Cr hybrid nano metal matrix composites from 50 °C to 300 °C. Al6061 based metal matrix composite reinforced with varying wt.% of Ni and Cr nanoparticles whereas fixed wt.% of graphene and Mg added to improve thermal conductivity, self-lubrication, and wettability. Thermal diffusivity, specific heat, and density were evaluated using laser flash apparatus (LFA 447), differential scanning calorimetry (DSC), and Archimedes principle, respectively. Results revealed that the thermal conductivity of fabricated composites increases with Ni, Cr, Mg, and graphene nanoparticles. With further expansion of reinforced particles of Ni and Cr, the thermal conductivity decreases. Finite element analysis (FEA) has been conducted to determine the thermal gradient and thermal flux using experimental values such as density, thermal conductivity, specific heat, and enthalpy at various temperature ranges to validate the experimental results.

Powder assembly & alloying to CNT/Al–Cu–Mg composites with trimodal grain structure and strength-ductility synergy

A novel strategy of powder assembly & alloying was used to achieve trimodal grain structure in carbon nanotubes (CNTs) reinforced aluminum matrix composites. The soft pure Al and hard 2024Al powders were firstly ball milled with CNTs for CNT/Al and CNT/2024Al flakes with different thicknesses, then were assembled with coarse-grained pure Al powders. Under the confinement of CNTs, these three building blocks evolved into ultrafine grains (UFG) smaller than 500 nm, fine grains (FG) between 500 nm and 2 μm and coarse grains (CG) about 9.8 μm, respectively, while the Al–Cu–Mg matrix achieved by the diffusion of Cu and Mg powders and elemental alloying with Al. Such a UFG-FG-CG trimodal grain structure contributed to superior strength-ductility synergy, as the 1.5 wt% CNT/Al–Cu–Mg composites exhibited tensile strength of 723 ± 6 MPa and elongation of 6.7 ± 0.6%. Therefore, powder assembly & alloying was proved an effective way to design and fabricate heterogeneous structured metal matrix nanocomposites.

Strengthening Mechanisms in Carbon Nanotubes Reinforced Metal Matrix Composites: A Review

Carbon nanotubes (CNTs)-reinforced metal matrix composites are very attractive advanced nanocomposites due to their potential unusual combination of excellent properties. These nanocomposites can be produced by several techniques, the most reported being powder metallurgy, electrochemical routes, and stir or ultrasonic casting. However, the final mechanical properties are often lower than expected. This can be attributed to a lack of understanding concerning the strengthening mechanisms that act to improve the mechanical properties of the metal matrix via the presence of the CNTs. The dispersion of the CNTs is the main challenge in the production of the nanocomposites, and is independent of the production technique used. This review describes the strengthening mechanism that act in CNT-reinforced metal matrix nanocomposites, such as the load transfer, grain refinement or texture strengthening, second phase, and strain hardening. However, other mechanisms can occur, such as solid solution strengthening, and these depend on the metal matrix used to produce the nanocomposites. Different metallic matrices and different production techniques are described to evaluate their influence on the reinforcement of these nanocomposites.

Effect of reinforcing graphene nanoplatelets (GNP) on the strength of aluminium (Al) metal matrix nanocomposites

Materials, with high strength applications, are always high in demand for the industry. Metal matrix composites play an important role in providing these materials. In the present study, Aluminium (Al)-graphene nanoplatelets (GNP) nano composites (Al-GNP) were fabricated through the route of powder metallurgy. Pure Al was used as matrix material and GNP (C-750) was used as reinforcement. The process consists of different steps viz dry ball milling followed by compaction and sintering. Compression and hardness test were performed on the formed samples. Four types of composites were fabricated with different proportions of GNP (0.1 wt%, 0.25 wt%, 0.5 wt% and 1 wt%) and the results were compared with pure Al made with the similar process. Morphological characterization like XRD, SEM and FTIR of the formed samples was also performed. It was found that both the hardness and compressive stress were increased up to a certain proportion of GNP in Al-GNP. The maximum hardness achieved was 23 HV with 0.25 wt% GNP which was 98.2 % more than the hardness value of pure Al. Similarly, the maximum compressive stress achieved was 109.33 MPa which was 59.18% high than the compressive stress of pure Al.