Particle Reinforced Metal Matrix Composites Research Articles

Influence of calcined snail shell particulates on mechanical properties of recycled aluminium alloy for automotive application

Nowadays, low-cost particulate reinforced metal matrix composites with improve mechanical properties are highly sought in various industrial and critical engineering applications including automotive and aerospace sectors. Meanwhile, increasing consumption rate of African giant land snail (Archachatina marginata) had been posing disposal challenges of its shells. Therefore, this paper tends to investigates the influence of waste snail shells particulates on the physical and mechanical properties of recycled aluminum- silicon alloy matrix. Different weight proportions i.e. (0 - 7.5) wt% of calcined snail shell particles at an interval of 1.5 wt% were successfully incorporated into Al-Si alloy matrix melted at 750 ?C using stir-casting route. The microstructure, physical and mechanical properties of the resulting composites were examined and presented. Microstructural examination shows fairly uniform dispersion of snail shell particles in the aluminium alloy matrix intermingled with aluminium-silicon dendrites. Mechanical properties such as hardness, impact, compressive and tensile strengths increased with increasing addition of calcined snail shell particulate up to 6 wt% while density and elongation decreases. The total equivalent density reduction of 5.4% in composites compared to unreinforced alloy was obtained at 7.5 wt% snail shell addition. The maximum hardness, impact, compressive and tensile strengths obtained are 118?4 HV, 88 J, 552?20 MPa and 211 ? 4.8 MPa equivalent to 21, 25, 19 and 36 percent increase respectively relative to un-reinforced aluminium-silicon alloy. Hence, mechanical and physical properties of Al-Si alloy can be enhanced using calcined snail shell particulates which can widen its application in automotive industries.

Plastic deformation and fracture behaviors in particle-reinforced aluminum composites: A numerical approach using an enhanced finite element model

A microstructure-based comprehensive finite element model, which incorporated the deformation/fracture of the matrix alloy, fracture of the particle and decohesion of interface, was built to predict the effects of particle size and shape on the plastic deformation and fracture behaviors in particle-reinforced metal matrix composites. The effect of particle size on the yield strength and work hardening rate of the matrix alloy was demonstrated. When the particle diameter is <10 µm, the fracture of the matrix alloy near the interface dominates the failure mechanism of the composite, whereas changed to particle fracture with particle diameter >10 µm. A cohesive zone model was also included in order to predict interfacial failure behavior. It was noted that SiC/Al interface exhibits a high interfacial bonding strength and the interfacial decohesion was caused by crack propagation from the particle to the interface. The simulation results are in good agreement with the experiment tensile test results in the SiCp/6061Al composite.

Synthesis and Characterisation of B4C reinforced Al6061 Friction Stir Processed Surface Composites

Current industrial trends show increased usage of lightweight high strength materials such as Aluminium, Titanium, Magnesium, etc., in their products and components. To achieve an improved service life, particulates reinforced metal matrix composites are being favored over the monolithic alloys. Researchers have reported undesirable defects and interfacial reactions while trying to fabricate such composites using conventional methodologies. This motivates the present work to use friction stir processing, an allied process of friction stir welding, to fabricate metal matrix composites. Structurally stable and most commonly used AA6061 alloy was taken for the experiment. B4C particles were used as reinforcements. Experiments were carried out using different process parameters like tool revolution and tool traverse speed or processing speed along with a constant axial force. The B4C particles were packed into a 1.5 mm groove on the Al6061 plate and friction processing was carried out. The SEM investigations on the composites showed a defect-free microstructure with a homogeneous distribution of reinforcement particles. It was found that the reinforcements increased the tensile strength of the composite by 50%. The hardness and wear-resistant properties of the composites had also improved considerably.

Influence of stir casting parameters on particle distribution in metal matrix composites using stir casting process

Particle Reinforced Metal Matrix Composites are generally utilized for various mechanical applications. The main objective of this study is on obtaining uniform particle distribution in metal matrix composites using the stir casting method. The significant part of this work is the experimental investigation of the stir casting technique in a crucible and the effect of stir casting parameter on uniform distribution of particles. The main challenge facing this project is the enhancement of the distribution of particles in molten metal. Silicon Carbide (SiC) and Aluminum alloy (Al-8011) have been proposed as reinforcement and matrix materials respectively. The effect of various parameters such us holding time, blade angle, impeller position and volume concentration for two different viscosity levels (1.24mPa-s and 1.04mPa-s) have been investigated. Composite microstructure has been characterized using Optical Microscope and Scanning Electron Microscope (SEM) in order to find the particle distribution in the composite. The mechanical behavior of the MMC has been assessed based on optimized stir casting parameter for uniform particle distribution.

An enhanced finite element model considering multi strengthening and damage mechanisms in particle reinforced metal matrix composites

A finite element (FE) model of particle reinforced metal matrix composite (PRMMC) was developed by considering load transfer, grain refinement, thermal residual stress/strain, plastic strain gradient and damage of the matrix together. This new model provides precise prediction of the tensile stress-strain curves of PRMMC, even when the size of particles varies. Using the new model, the effect of each strengthening mechanism was assessed quantitatively. According to the results, grain refinement is the main reason causing size effect, while strain gradient only causes higher work hardening rate for PRMMC with smaller particles. Load transfer plays a dominant role among other strengthening mechanisms. Residual stress/strain shows steady but small effect in strengthening PRMMC.

Machining of particulate-reinforced metal matrix composites: An investigation into the chip formation and subsurface damage

This paper develops a microstructure-based model for investigating the mechanisms of chip formation and subsurface damage in the machining of particulate-reinforced metal matrix composites (PRMMCs). The morphology and distribution of the particles, the debonding of the particle-matrix interface and the fracture of particles and the matrix were comprehensively integrated into the modelling. The numerical analysis was also verified by relevant cutting experiments. It was confirmed that the established model can accurately predict the machining process, including chip morphology, subsurface deformation and cutting forces. It was found that the depth of cut significantly influences the machined surface integrity and cutting forces. Particle fracture mainly occurs along the primary shear zone in the cutting path. High strain and stress concentration induced by the extrusion of the cutting edge or large particles on the machined surface can also cause particle fracture beneath the cutting path. The brittle fracture of the particles located in the cutting path can form large cavities; while the deformed matrix material can partially cover these cavities to form a smooth surface. The matrix deformation occurs primarily along the shear plane, and the chip segments are separated easily along the plane with clustered particles. Serrated chips are formed in cutting the A359/SiC composite.

3D Micro-Structural Modeling of Vibration Characteristics of Smart Particle-Reinforced Metal-Matrix Composite Beams

In this study, the effects of micro-structural parameters such as particle volume fraction, size and random distribution of Al 6061/SiC particulate metal-matrix composite (MMC) beams on free vibration response and the active vibration control are investigated. For this purpose, numerical particle-reinforced MMC (PRMMC) beam specimens were modeled with 3D finite elements, and the cubic-shaped reinforcing SiC particles were randomly distributed in Al 6061 metal matrix similar to an actual micro-structure. The particle size and especially volume fraction play an important role on the natural frequencies of the smart PRMMCs although they have no effect on the mode shapes. The random particle distribution has minor effect on the natural frequencies of the smart PRMMCs. With the increase of the feedback control gain, both the vibration amplitude and the suppression time are reduced reasonably. Increasing the particle volume fraction induces an important reduction in the damping time and the vibration amplitude for both the controlled and uncontrolled damped vibrations. Finally, increasing the particle size decreases the vibration suppression capacity and increases the vibration amplitude and time slightly. Random particle distribution had no obvious effect on the uncontrolled and controlled vibrations.

Controlling Particle/Metal Interactions in Metal Matrix Composites During Solidification: The Role of Melt Viscosity and Cooling Rate

The homogenous dispersion of particles in a metal matrix is of critical importance to the design and manufacturing of particle-reinforced metal matrix composites (MMCs). This work studied the effects of increasing melt viscosity via microalloying and increasing cooling rate on the dispersion of particles in an aluminum-based MMC. A CALculation of PHAse Diagrams (CALPHAD)-based viscosity model was developed for the Al-Ni binary system. This viscosity model was coupled with a particle-capture model to explore particle/metal interactions during solidification. Three composites (Al + TiCp) with and without Ni were cast at different cooling rates. The first composite without Ni cast at a lower cooling rate showed macro-segregation and agglomeration of TiCp along the grain boundaries. The second composite without Ni cast at a higher cooling rate exhibited grain refinement and reduced macro-segregation of TiCp. The third composite alloyed with 1 wt pct Ni and cast at the same higher cooling rate had an improved distribution, and particles > 2 µm in size were captured in the grains. The composite with 1 wt pct Ni had a 45 pct higher melt viscosity and a 31 pct lower critical velocity for capture of TiCp, demonstrating a synergetic effect of increasing viscosity and cooling rate on improving particle dispersion in MMCs.

A Bayesian statistics based investigation of binder hardening’s influence on the effective strength of particulate reinforced metal matrix composites (PRMMC)

In order to understand how hardening of the binder phase in particulate reinforced metal matrix composites (PRMMC) influences the effective strength, we present in this work a numerical framework consisting of the direct method (DM) and statistical models. Using this approach we created a large number of statistically equivalent representative volume element (SERVE) models to represent an exemplary PRMMC material WC-20 Wt.% Co and predicted its effective strengths using DM. After the global strength was calculated from each SERVE sample all derived data are interpreted by Bayesian network and diagnostic testing. By doing so the relationship between material strength and few selected characteristics have been clarified. The study shows the formulated approach as a novel means for investigating how the overall mechanical properties of random heterogeneous materials react to a certain constituent. Meanwhile, the study also demonstrates how statistical models, in particular the Bayesian network, can be used as a powerful supplement to micromechanical models for result analysis and knowledge discovery.

Mach inability Studies on Metal Matrix Composite’s Using Abrasive Water Jet Machining

The non-traditional machining of particulate reinforced metal matrix composites is relatively new. This paper covers studies on match inability of aluminium - Boron carbide metal matrix composites (Al-B4C MMCs) with abrasive water jets (AWJs). Two different compositions of Al-B4C MMCs were processed with various mesh size, abrasive flow rate, transverse rate and water pressure with a view to identify the performance of the abrasive water jet machine for effective processing of MMCs with AWJs. The maximum penetration ability of AWJs in different MMCs was examined by conducting the experiments on trapezoidal shaped Al-B4C MMC specimens, prepared with stir casting method. Optical micrographs of MMC samples and scanning electron microscopic (SEM) examination of AWJ cut surfaces enabled to explain the trends of material removal by the abrasives. Analysis of results clearly indicated the choice of 80 mesh size abrasives, higher water pressure and flow rate and lower transverse rate for effective processing of Al-B4C MMCs with AWJs.

Recent Developments on Wear and Corrosion Behavior of Iron/Iron–Nickel Metal Matrix Composites Reinforced with Zirconia

This article reports a brief review on the effect of process parameters on mechanical and corrosion properties of Fe-/Fe–Ni-based composites. Particle-reinforced metal matrix composites (MMCs) have gained a special interest in the field of structural, mechanical, aeronautical, and aviation industries. Iron-based MMCs are the one which are in high demand for tribological applications due to the high strength and high abrasion resistance properties. Different techniques have been used by different researchers for enhancing different properties of these composites during the last several years. Optimization of processing parameters, e.g., milling time, milling speed, reinforcement content, sintering time, and temperature are important for the development of composites by powder metallurgy route. Alloying of Ni in Fe–ZrO2 MMCs is found to play an important role in matrix phase formation during sintering. During sintering, the formation of γ phase in the matrix retards reactive sintering between metal and ceramic particles. Effect of some of the processing parameters on phase formation and various properties such as density, hardness, dry sliding wear properties, and corrosion reported in our previous studies have been summarized for particulate reinforced Fe/Fe–Ni metal matrix composites.

Statistical investigation on influence of grain size on effective strengths of particulate reinforced metal matrix composites

In this paper, a numerical technique is presented for evaluating the influence of particle size in particulate reinforced metal matrix composites (PRMMCs) on two critical material parameters, namely, the ultimate strength and endurance limit. To demonstrate this technique a representative PRMMC material, tungsten carbide–cobalt hard metal (WC–Co), was selected. As a typical random heterogeneous material, WC–Co demonstrates a noteworthy randomness in its composite structure. In order to take this characteristic into consideration, a novel numerical approach is adopted in this work, which is a conjunction between so-called direct methods (DMs) and statistical analyses. As the approach requires a large number of samples to be evaluated, numerical efficiency in solving optimization problems resulted from DM is a critical issue. For the purpose of comparison with the lower bound formulation, a numerical scheme formulated from the upper bound method is selected in this work. Overall, the study clarifies how the material strength of WC–Co with a fixed binder content is influenced by the reinforcement WC particle size and shows how the proposed approach can be used as a viable means for investigating the relationship between properties and structural characteristics of PRMMC materials.

Strengths prediction of particulate reinforced metal matrix composites (PRMMCs) using direct method and artificial neural network

Predicting strengths and understanding how these values related to the underlying composite structure is essential for the design and application of particulate reinforced metal matrix composites (PRMMCs). In order to investigate how ultimate strength and endurance limit of an exemplary PRMMC material, WC-20 wt% Co, are related to other structural and mechanical characteristics, an integrated numerical approach consisting of direct methods (DM) and artificial neural network (ANN) is presented in this work. Using few features obtained from elastic and DM analyses as inputs, multiple regression and classification ANNs were established to predict global material strengths. With this approach, the study implied that the distribution pattern of the stress field, in particular the one pertained to the binder phase, has a nontrivial influence over global composite strengths.

Analytical modeling of surface roughness in precision grinding of particle reinforced metal matrix composites considering nanomechanical response of material

Grinding is usually applied for particle reinforced metal matrix composites (PRMMCs) to achieve high ground surface quality. However, the surface quality especially surface roughness is difficult to predict theoretically due to different mechanical properties of two or more phases inside the PRMMCs. In this study, an analytical model of the surface roughness of ground PRMMCs is developed based on an undeformed chip thickness model with Rayleigh probability distribution by considering the different removal mechanism of metal matrix and reinforcement particles in grinding. GT35, a typical kind of steel based metal matrix composite reinforced with TiC particles is investigated as an example. Nanoindentation experiments are employed for the investigation of nanomechanical properties and cracking behavior of GT35 and the nanoindentation results are integrated in the model. Single factor surface grinding experiments of GT35 are also carried out to understand the material removal mechanism of GT35 and validate this novel surface roughness prediction model. The predicted surface roughness from this model shows good agreement with the experimental results.

Mixed regulation model of ceramic particles with molten high-chromium iron KmTBCr26

Particle reinforced metal matrix composites have many problems such as complicated preparation process, high production costs, weak interface bonding between the ceramic and metal matrix, uneven distribution of ceramic particles and so on. To solve these problems, the method of “shoot mixing + pressure compositing” (SM-PC) and a mixed regulation model of ceramic particles with molten steel were proposed. In the shoot mixing process, the special designed die casting equipment was used to make the particles with the molten metal mixed in the runner at a certain ejection speed (150 mm·s−1). After the mixture is filled with the mold, the pressure is maintained until the end of solidification. In order to optimize this method to obtain the more uniform particle distribution, the parameters (ejection speed, preheating temperature of particles, the shape and size of runner) in the model were selected for sample preparation. Taking the distribution index of particles as the evaluation criterion, it is concluded that the uniform distribution of particles can be promoted with the increase of ejection velocity, the increase of particle preheating temperature, and the small change of gate size. When the preheating temperature of particles was 1,100 °C, and the shape of the runner was trumpet, the optimal particle distribution composite parts was obtained. Meanwhile, the particles and the matrix achieved strong interface bonding — “Class I interface” under the pressure compositing, even though they’re non-wetting.

An experimental investigation on surface generation in ultraprecision machining of particle reinforced metal matrix composites

Ultraprecision machining of metal matrix composites (MMCs) is observed as a scientific challenge, due to their hard-to-machine property and often the poor surface finish. This paper presents an experimental investigation on surface generation in ultraprecision machining of Al/B4C/50p MMCs. The machining trials using straight flute polycrystalline diamond (PCD) tools are conducted on a high precision micro milling machine. Side milling is adopted under varied cutting conditions. Metrology assessments on the workpiece surface roughness, topography, texture and defects/features are undertaken using a ZYGO 3D surface profiler and a scanning electron microscope (SEM). Experimental results indicate that process parameters and their contributions play essential roles in the machining process. By applying the optimal process parameters, e.g. cutting speed of 188.496 m/min, feed rate of 10 μm/rev and axial depth of cut of 150 μm, a better surface generation with surface roughness Ra < 20 nm can be obtained in ultraprecision machining of Al/B4C/50p particulate MMCs.

Enhanced machinability of SiC-reinforced metal-matrix composite with hybrid turning

Particle-reinforced metal-matrix composites are promising engineering materials thanks to their superior mechanical and thermal properties. However, their poor machinability is a deterrent for use in wider applications, due to the presence of hard ceramic particles, which results in rapid tool wear during machining. Ultrasonically assisted turning (UAT) is a hybrid machining technique, in which the cutting tool is made to vibrate at high frequencies and low amplitudes. In this study, the machinability and tool wear of machining SiCp/Al metal matrix-composite was compared for dry UAT and conventional turning with the use of a cemented carbide (WC) and a polycrystalline diamond (PCD) tool. With the use of ultrasonic assistance, a significant reduction in cutting forces was achieved with a slight increase in cutting temperature. Continuous and semi-continuous chips were obtained in UAT, with better surface topography. A chip-formation mechanism in UAT show increased ductility of the workpiece material when subjected to a repeated high-frequency microchipping process. Abrasive and adhesive wear occurred on the WC tool in both conventional turning and UAT. However, the machined surface obtained in UAT with a WC tool was comparable and sometimes even better than that achieved with the PCD tool.

Microstructure-based modelling of fracture of particulate reinforced metal matrix composites

This paper aims to develop a microstructure-based model to describe the material deformation and fracture of the particulate reinforced metal matrix composites. The A359/SiC composite was used as a material example. The most important factors, such as particle morphology, distribution and fracture, matrix deformation and failure, and particle-matrix debonding, were comprehensively integrated into the modelling. Relevant experiments were also conducted. It was found that such a microstructure-based model can capture the major material deformation and failure mechanisms. The particle geometry and distribution can be described by normalized shape factor and clustering distance. Stress concentrations occur at the clustered particles, especially at the sharp corners, particle-matrix interfaces and the edges along the loading direction. The stress in the matrix is much lower than that in the particles and concentrates along 45° to the loading direction. Matrix-particle debonding is not noticeable. Particle fracture happens near its sharp corners, while matrix failure initiates around the particle crack tips and propagates to connect the microcracks caused by particle fracture, or through the area with high stress/strain concentration, leading to the fracture of the whole workpiece.

Research Status on Strengthening Mechanism of Particle-reinforced Metal Matrix Composites

Research Status on Strengthening Mechanism of Particle-reinforced Metal Matrix Composites

Interface model of the influence of particle size on the plastic deformation resistance of particle-reinforced metal-matrix composites

An interface model is proposed for the analysis of the influence of particle size on the plastic properties of metal matrix composites (MMCs). Dimensional effects are considered through surface strains and shear stresses at the interphase boundary. In comparison with the theories of the gradient of plastic strain, the proposed model greatly simplifies the analysis of dimensional effects. To calculate the plastic deformation diagram of an MMCs with an arbitrary particle size, it is sufficient to know the experimental diagram with one basic particle size and a theoretical diagram of deformation. The theoretical diagram is calculated using one of the classical models of homogenization. The results of calculating the deformation diagrams are in good agreement with the experimental data for aluminum MMCs reinforced with silicon carbide particles of various sizes.