Volume Fraction Of Reinforcement Particles Research Articles

Influence of Particle Sizes and Volume Fractions on Fatigue Crack Growth Rates of Aerospace Al-Alloys Composites

Recently, the need to develop fuel efficient transport systems has led to the development of a range of materials of low density, high stiffness and high strength each can be made at a reasonable cost. The aluminium based alloys are particularly important because of their improved mechanical, physical and technical properties. Fatigue failures have been recognised since the early days of the industrial revolution. Fatigue response of most of materials is related with the microstructural variations in the structure. Hence, in this study, influence of particle size and volume fractions on fatigue properties of Al-alloy composites was investigated. It was found that particle size and volume fraction of reinforcement particles play significant role on fatigue propagation rates, stress intensity threshold values, crack tip opening distance and crack tip plastic zone sizes.

Fabrication and microstructural characterization of Al-SiC based functionally graded disk

PurposeThe purpose of this study is to investigate the performance of disks that can be increased by functionally grading the disk in the radial direction; there are several but distinct categories of literature that pertain to the fabrication of disk in the thickness direction, but to the best of the authors’ knowledge, no study has been conducted yet, in which gradient composition changes radially.Design/methodology/approachA powder metallurgy technique was used for the fabrication of Al-SiC-based, three-and five-layered functionally graded (FG) disk. The variation of volume fraction of reinforcement particles (SiC) in a disk changes radially. Finite element analysis has been performed to investigate stress distribution in a layered disk.FindingsThe microstructural investigation was carried out under an optical microscope and scanning electron microscopy integrated with EDS, confirming a uniform distribution of SiC in the matrix (Al). Interface microstructure indicates a successful fabrication of FG material because the transition is uniform in the graded layer without any development of crack or void at the interface. The grain size in the layers decreases with the addition of SiC particles. Additionally, the disk hardness increases as the SiC composition in the layer increases.Practical implicationsAn FG disk can be used in a wide range of machinery, from power transmission assemblies to energy storage devices (e.g. flywheel, gears, rotors and disk brake).Originality/valueThe proposed powder metallurgy technique could be used in industries for the fabrication of simple to complicated geometries with FG properties.

A study on damage evolution in Cu–TiO2 composite fabricated using powder metallurgy followed by hot extrusion

In this paper, damage evolution of Copper/Titanium Dioxide, fabricated by powder metallurgy, based on Young modulus reduction is investigated. The Cu matrix is reinforced by different volume fraction of TiO2 nano and micro particles using mechanical milling, cold pressing at different loading rates (Quasi-Static, Drop Hammer, Split Hopkinson Bar), and hot extrusion process. The composite tensile test specimens were produced using powder metallurgy (cold pressing) followed by hot extrusion. The effects of the strain rate and the reinforcing particles size on damage evolution of Cu reinforced by 0, 2.5 and 5% volume fractions of nano- and micro-sized TiO2 were investigated. The results showed that the Quasi-Static method was more efficient than the other two methods. In addition, the experimental results showed that strain rate, plastic strain, fracture strain, volume fraction of reinforcement particles and particles aspect ratio were effective on damage evolution. Finally, these effective parameters were incorporated into a new model proposed to predict the damage evolution of Metal Matrix Composite (MMC). The model was validated by experimental results.

A literature survey on effect of various types of reinforcement particles on the mechanical and tribological properties of aluminium alloy matrix hybrid nano composite

This review paper deals with the individual and hybrid nano composites reinforced with different types of nano particles like, synthetic ceramic, agro-waste and industrial waste materials. A current demand in market is shifting from micro size to nano size particle reinforcement for hybrid nano composites and subsequently development in addition of synthetic ceramic particles incorporated with agro-industrial waste materials. The production of metal matrix composites reinforced with nano-particles attribute in varying the mechanical and physical properties than the base matrix. Hybrid nano composites are creditable choice that can overcome the drawbacks of monolithic and hybrid micro-composites. The reinforcement of nano-particles can enhance the properties of base matrix material in the form of corrosion resistance, wear resistance, mechanical strength and damping properties. This review look up the possibility of developing elite nano composites parts with several benefits such as light weight, low cost, sustainability, high strength to weight ratio and product variety for use in various structural application including aerospace, marine automobile, sports industries. Present review focus on the improvement in corrosion resistance, mechanical properties (like: hardness, tensile and compressive strength) wear resistance and fatigue properties of metal matrix hybrid nano composites [MMHnCs]. This study also discusses the influence of morphology of particles such as shape, size and volume fraction of reinforcement particles on the properties of [MMHnCs]. The important techniques of manufacturing of MMHnCs to improve the mechanical properties have been reviewed in detail.

Microstructure and mechanical properties of Al–Si–Cu–Fe alloy-based ceramic particle-reinforced nanocomposites and microcomposites and a modified model to predict the yield strength of nanocomposites

The effects of volume fraction, size, and type of reinforcement particles on the microstructure and mechanical properties of Al–Si–Cu–(Fe) alloy matrix composites were investigated and an analytical model was modified to predict the yield strength of the particle-reinforced nanocomposites. Nano- and micro-particle-reinforced Al–Si–Cu-(Fe) matrix composites (N-AMCs and M-AMCs) were manufactured by adding two different types and sizes of reinforcement particles to Al–Si–Cu–(Fe) alloys at different volume fractions using a two-step stir casting method combined with a high-energy ball milling process and a high-pressure die-casting method. Microstructural analyzes of N-AMCs and M-AMCs were performed using SEM, EDX, and XRD. The Brinell hardness test and the tensile test were carried out to determine the mechanical properties of the N-AMCs and M-AMCs. The hardness of the N-AMCs and M-AMCs was continuously enhanced by increasing the volume fraction of the reinforcement particles, while the yield strength and ultimate tensile strength of the N-AMCs and M-AMCs were improved up to 1.5 vol.% and 4 vol.% of nano-particles and micro-particles, respectively. An analytical model was modified to predict the yield strength of N-AMCs by integrating the effective volume ratio of nano-particles into each strengthening mechanism. The results predicted by the modified model reached nearly 98% agreement with the experimental results up to 1.5 vol.% of the reinforcement particles. Nano-particles had a much greater effect on strengthening mechanisms compared to micro-particles.

A parallel and efficient multi-split XFEM for 3-D analysis of heterogeneous materials

We propose a parallel and computationally efficient multi-split XFEM approach for 3-D analysis of heterogeneous materials. In this approach, multiple discontinuities (pores and reinforcement particles) may intersect any given element (we call those elements multi-split elements). These discontinuities are modeled by imposing additional degrees of freedom at the nodes. The main advantage of the proposed scheme is that the mesh size remains independent of the relative distance among the heterogeneities/discontinuities. The pores and reinforcement particles are assumed to be spherical. The simulations are performed for uniform and non-uniform heterogeneity distribution. The Young’s modulus of the heterogeneous material is evaluated for different amount of pores and reinforcement particles. To demonstrate the computational efficiency of the multi-split XFEM, elastic damage analysis is performed for the unit cell with 5% pores and 5% reinforcement particles under uniaxial tensile loading. These simulations show that the Young’s modulus decreases linearly with the increase in the volume fraction of the pores and increases linearly with the increase in volume fraction of reinforcement particles. The multi-split XFEM is found to be at least 1.8 times computationally efficient than standard XFEM and at least 6.7 times computationally efficient than FEM.

Effect of Reinforcement Volume Fraction on the Wear Behavior of Al-SiCp Composites Prepared by Spark Plasma Sintering

Most investigations on MMCs were carried out using conventional methods. Employing a different approach, this study concentrated on compaction, hardness and wear behavior of Al-SiC composites with different reinforcement volume fractions (5–15%) by spark plasma sintering method. Hardness and density test results of the composite samples used in this study were significantly higher than conventionally produced composites. Such increase in density and hardness resulted in lower wear rate. To study the effect of applied load on samples wear behavior, wear tests were carried out under 1, 3 and 10 N loads with 0.07 m/s sliding rate. Results revealed that in all the applied loads, composite samples had lower wear rates and lower friction coefficients than those of unreinforced aluminum. Conversely, increase in volume fraction of reinforcement particles led to decrease in wear rates and friction coefficients of the composite specimens which were more tangible in Al-15%SiC sample. Obtained data showed that by increasing the applied load, friction coefficient and wear rate increased in all the samples. Also dominant wear mechanism was determined using SEM micrographs of sample surfaces after wear tests.

A two-scale stochastic framework for predicting failure strength probability of heterogeneous materials

In the present study, a two-scale stochastic framework has been proposed for predicting the failure strength probability of heterogeneous materials. The analysis at both scales (meso and macro) is performed under plane stress condition. The meso-scale analysis is performed by XFEM whereas the macro-scale analysis is performed by FEM. The heterogeneities (pores and reinforced particles) are considered at meso-scale. The effect of shape, size, clustering and volume fraction of heterogeneities is analyzed at meso-scale. A new scheme is developed for modeling the arbitrary shape heterogeneities using periodic B-splines. An adaptive hanging node mesh refinement technique is employed to reduce the computational cost. Maximum principal stress failure criterion has been implemented for modeling both tensile and compressive behaviors at meso-scale. The volume fraction of pores and reinforcement particles is distributed stochastically to the elements at macro-scale. The average volume fraction of the pores is taken as 8%, 10%, 12% and 14% whereas the average volume fraction of the reinforced particles is kept constant at 20%. The statistical analysis of numerical data is performed through normal and Weibull distribution fits. K-S goodness of fit predicts that the numerical data is better fitted by the normal distribution.

Effect of SiC particles on thermal conductivity of Al-4%Cu/SiC composites

In this research, SiC powder with various volume fraction (10, 15, and 20%) and particle size (45, 100 and 150 μm) was mixed with Al-4% Cu alloy powder in order to synthesize Al-4%Cu/SiC composite using powder metallurgy technique. To investigate the microstructure and surface morphology of the prepared composites, scanning electron microscopy (SEM) was used, which revealed a homogeneous distribution of the SiC particles in the matrix. Results revealed that by increasing the volume fraction and SiC particle size, heat transmission of the Al-4%Cu/SiC nanocomposite enhanced up to 10.3%. Also, Hasselman-Johnson model was employed to analyse the experimental results, and it was concluded that with the increasing of volume fraction of reinforcement particles, the prediction model gets closer to the obtained experimental data.

Effect of reinforcement type, size, and volume fraction on the tribological behavior of Fe matrix composites at high sliding speed conditions

In this paper we studied the tribological behavior of iron matrix composites at high sliding speeds (25–35m/s) typical of aircraft braking conditions. We developed two types of Fe matrix composites with different elastic modulus reinforcements: silica (71GPa) and mullite (143GPa) particulates using powder metallurgy. Two different size ranges: large (150–250μm) and small sizes (1–10μm) and a range of volume fractions of the particulates were also considered. The dry sliding wear and braking performance of the composites were investigated using a sub-scale disc braking dynamometer. The wear tests of the composites show that large size and high volume fraction of reinforcement particles provides better wear resistance and braking performance at high sliding speed conditions (25m/s–35m/s) for both Fe/silica composites and Fe/mullite composites. Significantly, Fe/mullite composites at lower volume fractions showed greater wear resistance than the Fe/silica composites due to the higher elastic modulus of the mullite particles. A wear track examination of composites showed that different wear mechanisms were operative at the different speeds. Our results indicate that composites with a high volume fraction of large sized reinforcement particles of high elastic modulus are to be preferred for braking performance and low wear loss at high sliding speed applications.

Machinability of Aluminium Matrix Composites

The today's interest in MMCp results from a number of their creative properties, which can be designed through a proper selection of reinforcing components and technological parameters. The composite machine elements such us engine, compressor parts obtained by casting methods require the specially final machining. The introduction of hard ceramic particles increase wear resistance of composite material compared to unreinforcement alloy. Simultaneously increase wear and reducing the durability of tools cutting. The presence of ceramic particles (SiC, Cs) in aluminium matrix influence on surface geometry formed in track of processing. In this paper the results of investigations of geometry surface of composite after machining will be presented. Applied machining conditions for composite material were the same as for unreinforcement alloy, it made possible to compare the conditions of machining processing. It the piston skirt was conducted light profilometry investigation were the parameters 2D and 3D surface topography evaluated. Results shows dependency of surface parameters (Ra, Rz) after machining on kind, size and volume fraction of reinforcement particles applied in composite material.

Effect of Some Manfacturing Parameters on Machining of Extruded Al-Al2O3 Composites

A wide range of particulate metal matrix composites (PMMCs) of alumina and aluminum powders was formed using powder metallurgy techniques followed by extrusions at various extrusion ratios. The machining characteristics of the extruded PMMC were investigated. Results showed significant effects of weight fractions of reinforcement and extrusion ratios on tool wear and surface integrity of machined surface. The wear rate of cutting tool decreased rapidly with increasing the cutting parameters: cutting speed, feed, and depth of cut, however cutting speed is shown to be more effective. Sudden breakage of tool inserts occurred when the experiment started at high cutting speed. Wear rate has also decreased by decreasing volume fraction of reinforcement particles. Coating carbide tools have significantly improved the tool life. Coated tools showed 5% decrease in flank wear size compared to uncoated tools. This was valid within tested range of weight fractions and extrusion ratios. The surface finish of machined surfaces deteriorated when coated carbide tools were used. However, surface finish did not change significantly when volume fractions or extrusion ratios were altered.

Effect of the Reinforcement Volume Fraction on Mechanical Alloying of AA2124 – SiC Composite

Mixtures of AA2124 aluminum alloy powder and SiC particles at volume fractions of 10 vol.% and 20 vol.% were milled in a high energy planetary ball mill under an argon atmosphere, for times of 2.5h to 60 h, aiming to produce Al alloy-SiC nanocomposites. Optical microscopy (MO) and scanning electron microscopy (SEM) were used to evaluate the morphological and microstructural evolution of the powder composite, occurred during mechanical alloying. The crystallite size was determined using the Williamson-Hall method to analyze the X-ray peak broadening. It was observed that increasing the volume fraction of SiC, the mechanical alloying stages were accelerated: a finer composite powder was obtained at a shorter milling time as well as the morphology of the particles became more equiaxed. The XRD analysis showed the reduction of crystallite size of the aluminum alloy matrix with increasing milling time and that this effect is more pronounced with high volume fraction of SiC. The results show that the increase in the volume fraction of reinforcement particles increases the work hardening and fracture occurrence in the aluminum alloy powder during the milling, affecting the structural evolution of the composite.

Fatigue crack growth of SiC particle reinforced metal matrix composites

High stiffness ceramic reinforcement in a light alloy matrix can result in a substantial increase in fatigue resistance while maintaining cost at an acceptable level. The fatigue resistance of particulate metal matrix composites (MMCs) depends on a variety of factors, including reinforcement particle volume fraction, particle size, matrix microstructure and the presence of inclusions or defects that arise from processing. In particular, the crack growth behavior in particle reinforced MMCs is very much dependent on reinforcement characteristics, and on matrix microstructure. The goal of this work is to obtain a fundamental understanding of fatigue crack growth behavior and evolution of microstructure during fatigue. The ambient temperature fatigue behavior of 2080/SiC p composites was examined and compared to the behavior of the unreinforced alloy. In particular, the fatigue crack growth behavior of these materials as a function of R-ratio was quantified and modeled using the two-parameter (Δ K − K max) approach. The fatigue fracture behavior at different R-ratios was investigated and correlated with the fatigue response of the composite.

Comparing the effect of processing temperature on microstructure and mechanical behavior of (ZrSiO 4 or TiB 2)/aluminum composites

Recently, a large number of metal matrix composites have been developed for high-performance applications. The first requirement for superior performance of a composite material is the homogeneous distribution of the reinforcing phase. In particulate-reinforced composites, any agglomeration of reinforcement particles deteriorates the mechanical properties of composite. Stir casting route has been used to achieve homogeneity of particle distribution throughout the matrix. In present study, ZrSiO 4 and TiB 2 particles were incorporated in A356.1 alloy. The size of ZrSiO 4 and TiB 2 particles was 1 μm. Reinforcement particles were added to melted aluminum at different temperatures above pure aluminum melting point (750, 850, 950 °C). The volume fraction of reinforcement particles was 5%. After addition of reinforcement, stirring was continued for 12 min for better distribution and better solidification conditions. The microstructure and mechanical behavior of prepared composites were studied. Scanning electron microscopy and X-ray diffraction were used to investigate dispersion of reinforcement particles in aluminum matrix and chemical composition of composites. Hardness and tensile tests were carried out to test mechanical properties. The results of these experiments show that the mechanical properties and microstructure of composites were changed by increasing temperature; also the best condition of ZrSiO 4 case was 750 °C but 850 °C for TiB 2.

Creep Properties of Composite Solders Reinforced with Nano- and Microsized Particles

In the present work the creep properties of Sn37Pb- and Sn0.7Cu-based composite solders reinforced with metallic nano- and microsized Cu and Ag particles have been studied. First, a series of volume percentages of reinforcements were selected to optimize the content of reinforcing particles. Then, the composite solder with optimum volume fraction of reinforcement particles, corresponding to the maximum creep rupture lifetime, was selected to investigate the effect of applied stress and temperature on the creep rupture lifetime of the composite solder joints. In the creep rupture lifetime test, small single-lap tensile-shear joints were adopted. The results indicate that composite solders reinforced with microsized particles exhibit better creep strengthening than composite solders reinforced with nanosized particles, although the mechanical tensile shear strength of composite solder joints reinforced with nanosized particles may be higher than those reinforced with microsized particles. Moreover, the creep strengthening action of the reinforcement particles is more obvious under conditions of lower applied stress or lower test temperature. Strengthening by metallic Cu or Ag reinforcement particles decreases with increasing temperature or applied stress. The Sn0.7Cu-based composite solder reinforced with microsized Ag particles is a low-cost lead-free solder that is easy to process and may have good market potential.

Determination of densification behavior of Al–SiC metal matrix composites during consolidation processes

Powder metallurgy and vacuum hot pressing were used for the development of SiC-particle reinforced aluminum metal matrix composites. The effect of process conditions on the consolidation was investigated in terms of the relative density changes concurrent with microstructural evolutions. Increasing temperature or pressure led to increased densification rates. Applied pressure, however strongly influenced densification time for the materials. Levels of consolidation together with mechanical properties of the developed products also depended on the volume fraction of reinforcement particles. A constitutive model is presented to determine the densification behavior of the materials. The model was implemented into finite element software so process simulations could be carried out and the predicted relative density could be compared to experimental observations.

Novel Separation Technique of Particle Reinforced Metal Matrix Composites by Fused Deposition Method

To develop a novel separation technique of matrix alloys from metal matrix composite, separation experiments for various kinds of particle reinforced metal matrix composites (PRMMCs) were carried out. The Al-4mass%Cu alloy, Al-7mass%Si alloy and cast iron were used as matrix. The SiC particles (particle size: 75μm) and Al2O3 particles (particle size: 120μm) were used as reinforcement. The PRMMC specimen was placed in a silica tube container with a small nozzle (nozzle size: 0.75mm) at the bottom and was melted by H.F. induction heating. Then the molten PRMMC specimen was forced to flow out through the nozzle by applying a certain pressure of Ar gas. Most of the molten matrix alloy flowed out through the nozzle and the remainder in the container consisted of the reinforcements and a part of the matrix alloy. The amount of separated matrix alloy increased with decreasing the volume fraction of reinforcement particles in PRMMC specimens. With decreasing the fabrication temperature from 1273K to 1073K, the amount of matrix alloy separated from SiCP/Al-7mass%Si alloy composites increased. It is considered that a reaction layer formed on the surface of SiC particles at 1273K improves the wettability between the molten matrix alloy and SiC particle, which prevents the separation of molten matrix alloy from reinforcements. On the other hand, the amount of separated matrix alloy from 20vol% Al2O3P/cast iron composites was very high due to no reaction layer formed at interface between Al2O3 particle and cast iron.

Matrix grain refinement in Al–TiAl composites by severe plastic deformation: Influence of particle size and processing route

The microstructure and mechanical behaviour of Al-based composites reinforced with TiAl intermetallic particles has been examined in the as-extruded state and after processing by equal channel angular pressing (ECAP). The latter produces a grain size reduction in the aluminium matrix to values of 500 nm, using route A, and 750 nm, using route C. The ECAP produces up to a 75% increase in the yield stress of the composites, being more rapid when route A is used. The strengthening effect by ECAP is much larger than that obtained by increasing the volume fraction of reinforcement particles from 25 to 50% in these composites.

Effect of equal channel angular pressing on strength and ductility of Al–TiAl composites

Severe deformation by equal channel angular pressing (ECAP) of extruded Al–TiAl composites have been studied to understand the influence on the microstructure and mechanical properties as a function of reinforcement particle size and distribution. Microstructure refinement to submicron grain size was already observed in the aluminium matrix after the first ECAP pass, with saturation occurring after four passes. The number of ECAP passes that the composites can sustain before fracturing decreases with the decrease of interparticle spacing, i.e, with an increase in volume fraction of reinforcement particles and/or the decrease in their size. The strength of the composites increases and the ductility decreases after processing by ECAP. The reduction of ductility occurs by weakening of the Al–TiAl interface due to stress concentrations accumulated by the severe deformation of the aluminium matrix.