Particulate Metal Matrix Composites Research Articles

Mechanical behavior of Al /AL2O3p-SiCp hybrid composite fabricated by hot pressing method

Hybrid particulate metal matrix composites with specific strength can be used in various applications. The mechanical properties of these composites can be improved by correctly choosing the type, volume fraction, size, and distribution of reinforcements and metal matrix. In this research, to make Al/Al2O3-SiC hybrid composites, aluminum chips were prepared by machining, and then the chips were coated with Al2O3 and SiC reinforcements by suspension method. For composite making, first, aluminum-coated chips were molded inside a steel mold and after heat treatment at 645 °C for 2 h the chips were hot pressed. The microstructure of the fabricated composites was examined by optical and SEM microscope, and then compression and tensile strength behavior were studied. The microstructural results showed a sound composite without any porosities and cracks. The hybrid composite with 12 wt% reinforcements showed high compressive strength (370 MPa).

Influence of distribution and size of graphite particle on the machinability of nodular cast iron

Nodular cast iron (NCI), also known as particulate metal matrix composites (PMMCs), is extensively utilized in the manufacturing of pistons for high-power engines. However, poor machinability is a significant problem due to the inherent microstructural inhomogeneity of the NCI. Therefore, this study aims to investigate influence of graphite particle distribution and size on the machinability of NCI. Microstructure of NCI is experimentally examined and quantitatively analyzed, and NCI is treated as a three-phase composite (i.e., matrix-interface-graphite particles). Graphite particles are considered as a plastic material, and debonding of interfaces is taken into account. Based on average particle size and volume fraction of graphite nodules, four microstructural models with different particle sizes and distributions are discussed, and turning experiments are conducted to validate simulation results. The findings reveal that graphite particles of different sizes and distributions affect stress–strain distribution in the cutting region of the material. As the distance between the graphite particles and the cutting tool increases, their influence on the stress–strain distribution becomes less significant. Furthermore, random distribution of graphite particles is more likely to result in complex crack initiation and expansion, leading to more pronounced serrated chips. The distribution of graphite particles has a more significant impact on the stability of cutting forces compared to the particle size. Both experiments and simulation results show that cavities and burrs are appeared along the cutting path because of graphite nodules, which reduces the surface quality and affects the subsequent use of the parts. On the one hand, the present work provides guidance for the finite element modelling of NCI, which is helpful to improve the precision of cutting simulation. On the other hand, by integrating advanced manufacturing technology to regulate the microstructure and cutting parameter of NCI, the present study can provide data basis and numerical analysis support for improving the machinability of NCI.

Novel Algebraic Matrix Method Used to Generate Linear Equation for Surface Roughness and Material Removal Rate during Wet/Dry Turning Operation on MMCs Al6061-T6/SiC

Stir casting process is well known for reinforcement of ceramic particle in aluminium. Due to improved properties of Al6061-T6/SiC particulate metal matrix composites have attracted by industry as well as received wider attention of material expertise. The purpose of this study is to evaluate the turning process parameters through algebraic matrix which is unique approach. Also studied effects of spindle speed, feed, SiC silicon carbide-3% and 6%, depth of cut and nose radius on modifier element for instance surface roughness Ra and material removal rate MRR in both dry and wet condition. In addition to optimize the turning process parameters are on Al6061-T6/SiC 3% and 6% with a coated tungsten tool. The experimental runs are designed using the taguchi based multiple factorial design DOE and their outcomes are analyzed using Analysis of Variance ANOVA. Mathematical models are established using algebraic matrix to represent the relationship among turning process parameters as independent variables, surface roughness and material removal rate as dependent variables. For every experimental run, a same cutting insert was used to encourage accurate reporting of the surface roughness and material removal rate. The statistical variations revealed that the main effect of spindle speed, feed, SiC silicon carbide-3% and 6%, depth of cut and nose radius are influenced the surface roughness and material removal rate. Moreover, Built-up-edge BUE formation was observed at every combinations of machining parameters such as spindle speed, feed, SiC silicon carbide-3% and 6%, depth of cut and nose radius which affected the surface quality negatively. The proximity of predicted results and experimental results provide proof that the algebraic matrix – DOE method has successfully established the predictive models. It is strongly suggested SiC silicon carbide 3% and 6% are successfully reinforced in Al6061 as well as optimize turning process parameters in wet condition than dry condition. Mathematical models for surface roughness and material removal rate are found to be statistically significant in wet condition.

Microstructure and mechanical properties of magnesium alloy reinforced with TiB2 and B4C processed through friction stir processing

Due to its light weight, particulate magnesium metal matrix composites have become a popular choice for industrial applications in the fabrication of vehicles. There were a few practical challenges with creating magnesium-based alloy composites, such as flammability and significant shrinkage. Despite the real time fabrication limitations, researchers are being attracted in magnesium metal matrix composites that are reinforced with particulate reinforcements due their high strength to weight ratio. Friction Stir Processing is one of the most widely used processes used to produce Magnesium metal matrix composites. Because of low process temperature, it is mostly impervious to chemical reactions that are caused during conventional manufacturing processes. The present research work emphasis on the development of AZ31alloy composite by friction stir processing reinforced with TiB2 and B4C particulate reinforcements. The effect of added reinforcement in mechanical properties like tensile strength, hardness, and wear performance were observed. The addition of TiB2 helps in improving the ultimate tensile strength of the magnesium MMC. SEM observations have shown that the number of passes increased it refined the grain size. Particle sizes were also seen to be reduced in size as the increment in passes. The variation in the tensile strength was not impressive; on the other hand, the hardness of FSPed samples has increased in comparison to the base material. Samples have shown improvement in resistance to the wear rate as an increase in traverse speed and it was seen to increase that resistance to wear was increased as the passes were incremented.

Indentation Plastometry of Particulate Metal Matrix Composites, Highlighting Effects of Microstructural Scale

Herein, it is concerned with the use of profilometry‐based indentation plastometry (PIP) to obtain mechanical property information for particulate metal matrix composites (MMCs). This type of test, together with conventional uniaxial testing, has been applied to four different MMCs (produced with various particulate contents and processing conditions). It is shown that reliable stress–strain curves can be obtained using PIP, although the possibility of premature (prenecking) fracture should be noted. Close attention is paid to scale effects. As a consequence of variations in local spatial distributions of particulate, the “representative volume” of these materials can be relatively large. This can lead to a certain amount of scatter in PIP profiles and it is advisable to carry out a number of repeat PIP tests in order to obtain macroscopic properties. Nevertheless, it is shown that PIP testing can reliably detect the relatively minor (macroscopic) anisotropy exhibited by forged materials of this type.

Mechanical Properties of Metal Matrix Composites: Short Review

This paper provides an overview of the increasing R&D activity in metal matrix composites worldwide, with a particular focus on cast particulate metal matrix composites. Large-scale applications of cast aluminum alloy MMCs in everyday use in the transportation and consumer durables industries are expected to advance rapidly over the next decade. India has great potential for widespread application of cast composites, especially in the fields of transportation, energy and electrical machinery. Widespread use of composites can result in significant material and energy savings and, in some cases, reduced pollution. It is important to organize engineering education and short courses to make students and engineering professionals aware of his MMC. India already has an excellent infrastructure for composites development and a long track record of world-class cast metal matrix composites research. Today there is a need to catalyze prototypes and series production of selected composite components and use them in various sectors, especially in railways, cars, trucks, buses, scooters and other electrical machines. This requires a well-funded strategy to bring together the world-class foundry composites talent already present in India to form a viable development group. We will then establish a manufacturing facility that incorporates the process engineering capabilities that already exist in the country. Cast composites must be developed for use in power generation equipment, aerospace electronic packaging systems, and smart structures.

Several Aspects of Interaction between Chrome and Nanodiamond Particles in Metal Matrix Composites When Being Heated

The paper considers the development of a technological scheme for preparing metal matrix nanocomposites based on the interaction between nanodiamond reinforcing particles and a chromium matrix when being heated, forming chromium carbide nanoparticles. These carbides are in situ synthesized ceramic reinforcing nanoparticles. The first stage of preparing composites is to obtain composites with the chromium matrix and nanodiamond reinforcing particles. For this purpose, mechanical alloying is used, i.e., processing in planetary mills. The size of a primary nanodiamond particle is 5 nm, but they are combined in agglomerates that are hundreds of micrometers in size. The time of processing in the planetary mill defines the crushing degree of the agglomerates. In this study, processing was carried out for 0.5 h, 2 h, and 4 h. The second stage for obtaining composites with reinforcing particles of chromium carbides is thermal processing. Explorations using the method of differential scanning calorimetry showed that reducing the size of nanodiamond reinforcing particles (by prolonging the time of processing in the planetary mill) leads to a decrease in the initial temperature of the reaction for developing carbides. The worked-out technique for obtaining composites was patented in the Russian Federation (the patent for invention 2772480).

Micro/nano-reinforcements in bimodal-grained matrix: A heterostructure strategy for toughening particulate reinforced metal matrix composites

To overcome strength-ductility trade-off in particulate metal matrix composites (PRMMCs), we developed a novel and controllable strategy, for the first time, via a combination of micro/nano-reinforcements and ultrafine/coarse-grained (UFG/CG) matrices. A powder assembly was developed to fabricate micro B4Cp/6061Al composites, which features UFG/CG matrices containing ex/in-situ nano dispersoids and exhibits superior combination of strength and ductility. It was found that such a novel architecture possesses both intrinsic and extrinsic toughening. As the intrinsic toughening mechanisms, enhanced dislocation storage capability of UFG regions, twinning, and hetero-deformation induced toughening were detected. Moreover, crack-deflection induced by nano dispersoids as well as crack-blunting at UFG/CG regions were considered as the main extrinsic toughening mechanisms. The proposed strategy can be applied to design the architecture of other PRMMCs with both high strength and high ductility. Aluminum alloys; Powder processing; Heterostructures; Particulate reinforced composites; Microstructural toughening

An overview of the effect of stirrer design on the mechanical properties of Aluminium Alloy Matrix Composites fabricated by stir casting

An overview of the effect of stirrer design on the mechanical properties of Aluminium Alloy Matrix Composites fabricated by stir casting

Additive manufacturing of aluminum metal matrix composites: Mechanical alloying of composite powders and single track consolidation with laser powder bed fusion

The thermomechanical properties of particle-reinforced metal matrix composites (MMCs) are attractive for many structural applications, but fabrication of MMC parts with conventional methods is difficult, costly, and typically limited to simple geometries. Additively manufacturing particulate MMCs with laser powder bed fusion (LPBF) would be an ideal method, but the laser consolidation of these materials has been largely unsuccessful in matching the properties of conventionally produced MMCs. The challenges include spreading the heterogeneous powder, distributing small ceramic particles, and forming a strong bond between the metal and the ceramic. Here, by mechanically alloying AlSi10Mg and TiB 2 , we manufacture highly-reinforced aluminum composite powders with morphology and composition tailored for LPBF process conditions. We show that this powder flows and packs similarly to gas atomized aluminum powder and can be consolidated into smooth, continuous tracks. Moreover, the method of feedstock powder production is scalable and commercially viable. Our results demonstrate conditions under which MMCs with high ceramic loading can be produced by additive manufacturing, potentially opening up many new applications for these high-performance materials.

Creep and Stress Relaxation Behavior of Metal Matrix Particulate Composites Induced by Interface Diffusion with Coupled Thermomechanical Strains

Creep and Stress Relaxation Behavior of Metal Matrix Particulate Composites Induced by Interface Diffusion with Coupled Thermomechanical Strains

Corrosion study on chill casting effect on aluminium A356 reinforced with Hematite metal matrix composites

In this article, an attempt have been made through investigate the effect of copper chill on Aluminium Metal Matrix Composites (AMMCs), and also to explore the corrosion resistance of the prepared Al A356-Hematite particulate metal matrix composites, which is cast through sand casting practice without and with copper chills at ends to get isotropic and homogeneous material properties under liquid metallurgical manner, by varying weight fractions of Hematite particulates assortments from 0 wt% −12 wt% in segments about 3 wt%. The test samples were prepared as per ASTM criteria. The prepared specimens were subjected to corrosion test and Micrographic analysis. The experiments were conducted to study the corrosion rate by weight-loss method, the specimens were soaked in 3.5% NaCl solution with a time intervals of 24 h to 96 h in steps of 24 h. Result shows that, the copper chill A356-Hematite composites shows lesser corrosion rate compare to without copper chill. Micrographic investigation has been executed using XRD (X-Ray Diffraction) patterns and SEM (Scanning Electron Microscope) photos. The presence of Hematite elements was conformed by XRD pattern and also revealed that the even distribution of Hematite elements in the A356 matrix alloy of composite casted with copper chills. It was also pragmatic that fine-grained structure is obtained due to rapid cooling which influences in enlightening the corrosion resistance of the composites with copper chills. And also due to an increased content of reinforcement in both without and with copper chill composites results in significant enhancement in corrosion resistance. The Copper chill specimens shows higher corrosion resistance than As-cast specimens.

Microstructural Evaluation and Mechanical Behaviour of Nano B4C Reinforced Al7475 Alloy Metal Composites

This paper details the synthesis of Al7475 alloy with 8% wt. of nano B4C particulate metal matrix composites using the liquid metallurgy technique. Scanning electron microscope (SEM) of the synthesized composites demonstrates the uniform dispersion of the reinforced nano B4C particles throughout the matrix. EDS spectrums confirmed the various elements present in Al7475-B4C composites. Hardness, tensile and compression tests were carried out to find out the impact of nano B4C on various mechanical properties of the composites. Synthesized composites had a greater hardness, tensile and compression strength with the incorporation of B4C particles. Tensile failure analysis was studied using SEM images of fractured surfaces.

Deformation mechanism in particulate metal matrix composites

A new approach based on modified stress and strain with considering micromechanics and dislocation theory, has been extended to find the deformation mechanism during hot deformation of particulate metal matrix composite. The impact of main influential processing parameters, such as temperature, strain, and strain rate in addition to reinforcement characteristics, i.e., particle size, and volume fraction, were successfully taken into account in the calculation of deformation activation energy and stress exponent. Besides, the effect of particle fracture, and diffusion relaxation around particles, were participated in the presented formulation. To evaluate the applicability of the developed formulation, different aluminum matrix particulate composites with different particle sizes and volume fractions were subjected to investigation. Using the modified recovery stress for calculating the activation energy, results in reduction of the stress exponent to a meaningful range. It was shown that deformation mechanisms in metal matrix composite and unreinforced alloy are the same. It was also found that for the low value of stress, i.e., the low strain rate and high temperature, the stress relaxation, and for the high value stress, the particle fracture, disturb the load transfer mechanism and reduce the impact of reinforcement on activation energy.

Surface characteristics modification of lm25 aluminum alloy – 5% sic particulate metal matrix composites by friction stir processing

Stir casting is employed for successful casting of aluminum-based metal matrix composite (MMC) plates of 12 mm thickness. Surface imperfections, porosity and reinforcement agglomeration are the main concerns in stir casting processes. Solid state friction stir processing (FSP) enhances mechanical characteristics by grain refinement and uniform distribution of reinforcement of MMC. Some of the crucial specifications of FSP include the tool traverse speed, tool rotational speed, tool shoulder diameter (D/d) ratio, pin design, pin length and axial force. In this investigation, five varying tool traverse speeds ranging between 20 mm and 60 mm per min were experimented on the stir cast plates. The wear rate, microstructure and microhardness evaluation on FSP plates revealed that wear resistance of 40 mm/min tool traverse speed FSP plate is superior and attribute to significant microhardness values. In addition, fine grains, uniform distribution and SiC particle bonding with aluminum matrix contribute to effective resistance to wear.

Effect of Cryogenic treatment on Wear Properties of Aluminum Al356 – Zirconium Silicate Particulate Metal Matrix Composite

Metal matrix composite (MMC’s) are very much familiar in the field like automobile and aerospace industries owing to their excellent wear and mechanical properties . The fundamental aim of this paper is to augment cognizance amongst the researchers and to attract their consideration towards the present approach to treat with the cryogenic usage for the nonferrous metals. In this writing it is endeavor to deliver the examination findings of character of cryogenic usage on Wear Properties of Al356-ZrSiO4 Particulate Reinforced metal matrix Composites adapted by Stir Casting technique. The amount of reinforcement is changed from 0 to 12wt% in track of 3 %. The ready composites are exposed to wear testing as per ASTM standards using pin on disc machine .The hardness of the composites was found to augment with augment in reinforcement in the composite. The inference obtained discloses that as reinforcement content in the composites increment and execution of cryogenic usage to composite amended the wear resistance.

Upper and lower bounds on the creep strain and stress relaxation induced by interface diffusion in metal-matrix particulate composites

In this study, we developed a micromechanics scheme to predict the upper and lower bounds on the creep strain and stress relaxation induced by interface diffusion in metal-matrix particulate composites. The normal stress acting on the matrix-inclusion interface, which is the driving force for interface diffusion, is estimated by using the Hashin-Shtrikman bounds and mean-field micromechanics theory. Analytical solutions of upper and lower bounds on the creep strain under constant stress and the relaxed stress at fixed strain are obtained. Results of this work show that the ultimate creep strain and relaxed stress are only related to the material properties and the percentage of each component, such as volume fraction of inclusion and elastic modulus ratio of inclusion to matrix. The parameters of interface diffusion only influence the rate of creep strain. It is found that the creep deformation and stress relaxation of composites are more sensitive to the volume fraction of inclusion than the elastic modulus ratio. The methodology of this study also applies to analysis of creep deformation of composites where both the matrix creep and interface diffusional creep need to be considered. The present study offers new perspectives for in-depth understanding of creep behavior of composites driven by mass diffusion along inclusion-matrix interface.

Effects of stir casting process parameters on dispersion of reinforcement particles during preparation of metal composites

Abstract The flow behavior of the liquid metal during the stir casting process significantly affects dispersion of reinforcement particles in Metal Matrix Composites (MMCs). Liquid metal processing is carried out in an opaque crucible, in which the flow patterns are invisible. Hence, numerical simulation is an apt tool to understand flow behavior and particle dispersion. Blade angle and stirring speed are two important factors ultimately resulting in the final quality of the composites. Thus, in the present investigation, simulation of stir casting process has been performed to optimize blade angle and stirring speed. In order to compare the results of simulation, MMCs were developed using a conventional stir casting technique. Microscopic investigation and porosity analysis has been incorporated to study dispersion of reinforcement inside molten matrix. Microstructural investigation unveiled the homogeneous distribution of SiC particles in the molten matrix and grain size of composite material is reduced by 10.5% as compared to matrix material.

Study of self lubrication property of Al/SiC/Graphite hybrid composite during Machining by using artificial neural networks (ANN)

Particulate-Metal Matrix Composites have captivated huge attention for a wide range of engineering applications because of their superior mechanical properties such as high strength, corrosion resistance and wear resistance. However, they lag behind high machinability (due to the presence of hard ceramic reinforcements) and involve expensive processing techniques that restrict their widespread application. The present work is aimed at improving machinability of Al alloy/SiC/graphite hybrid composite developed by a low-cost stir casting technique. Microstructure studies of the hybrid composite were investigated by using SEM and optical microscope. The obtained results were then correlated with mechanical properties to reveal significant enhancement when compared to AA2024 alloy without reinforcements. The machining forces of hybrid composite during drilling were studied by custom-designed strain gauge-based dynamometer. Machinability was improved with graphite incorporation, which has a self-lubricant texture, without much compromising the hardness and tensile strength of the hybrid composite. Further, neural network analysis was adopted by training the model to accurately predict the cutting forces to realize efficient composite with suitable machining parameters.

Investigation of optimum process parameter of lost foam casting of A356/SiC metal matrix composite

Metal Matrix Composites (MMCs) are unceasingly substituting engineering materials because of its high stiffness and strength over homogeneous materials formulation. It has been utilized in engineering structural applications like aerospace, automotive and defense. In industries MMCs are mostly fabricated by squeeze casting, stir casting, infiltration technique, and spray deposition technique. In these processes, there are some limitations like difficulties in producing intricate shapes, homogeneous distribution of ceramic particles and poor wetting property between reinforcement and matrix alloy etc. To overcome these limitations, Lost Foam Casting (LFC) is used to fabricate MMCs. In this investigation an attempt has been made to produce intricate castings of (A356 Al alloy-SiC) particulate type Metal Matrix Composites using LFC process. The rectangular expanded polystyrene (EPS) patterns are used in this LFC process instead of circular patterns. The LFC process quality is strongly affected by the elimination of degradation product which in turn depends on the process parameters such as sand grain size, coating grain size, pouring temperature and coating method. These four process parameters with three levels are considered for Taguchi’s technique with L9 Orthogonal Array (OA) and the experiments were conducted. Density and tensile strength of the castings are considered as quality characteristics of the LFC process. From the ANOVA results, it reveals that the sand grain size and coating grain size mainly influence the casting quality. The optimal process parameters are sand grain size of AFS 50, coating grain size of 212 µm, pouring temperature 800 °C and coating method of brushing technique.