Reinforced Metal Matrix Composites Research Articles

Influence of zircon particles on the characterization of Al7050-Zircon composites

Composite materials are widely used in aerospace, defense, automotive and structural applications due to its superior properties such as high strength, high stiffness, high corrosion resistance, high toughness and high wear resistance. Particulate Reinforced Metal matrix composites are extensively used in automobile applications due to its high strength and high temperature resistance properties. Al7050 alloy is an aluminium alloy, with zinc as the major alloying element. It is an easily available and light weight alloy. In the present research Al7050-Zircon composites were produced by using stir casting method by varying the weight percentage of zircon in steps of 0%, 2%, 4%, 6% and 8% by weight. The test specimens were prepared as per ASTM standards. The microstructure characterization of Al7050-Zircon composites were carried out using Scanning Electron Microscope. The hardness test of Al7050-Zircon composites were carried out using hardness testing machine. The tensile strength of Al7050-Zircon composites was carried out by using universal testing machine. The SEM micrographs of Al7050-Zircon composite show the occurrence of zircon particles in the Al7050 matrix. The SEM images show the homogeneous distribution of zircon particles in the Al7050 matrix. The hardness value of Al7050-Zircon composite is more than Al7050 alloy alone. The tensile strength of Al7050-Zircon composite is more than Al7050 alloy alone. The optimum value of hardness and tensile strength of Al7050-Zircon composite is obtained at 6% of Zircon.

Processing of an AA7050/Al Hybrid Composites Reinforced with Multiwalled Carbon Nanotubes

Abstract The development of carbon nanotubes reinforced metal matrix composites merits relevant attention due to its capacity of improve the hardness and strength of the metal. However, the production of this kind of composite presents many challenges, such as the dispersion and adhesion of carbon nanotubes in the metallic matrix, wich may affect the composite consolidation. The present study aimed the development of composites using an age hardening aluminum alloy reinforced with 0.5 wt.% of multiwalled carbon nanotubes (MWCNT) as well as a hybrid composite based on the mixture of pure aluminum powder and the former composite. AA7050 alloy and pure aluminum matrix composites were processed by ultrasonic mixing, hot pressing and hot extrusion. Subsequently, the materials were submitted to aging heat treatments. The samples were analysed by Scanning Electron Microscopy, X-Ray Diffraction, Atomic Force Spectroscopy, Raman spectroscopy, and Vickers microhardness. It was verified the feasibility in manufacturing the composites by the powder metallurgy route proposed in this work. The AA7050 composite reinforced with 0.5 wt.% MWCNT presented higher hardness than other similar composites in the literature with higher carbon nanotubes content. The aged composite hardness increased 72% in comparison with the present one in the as extruded condition.

The Influence of Porosity on the Statistical Amplitude Distribution of Backscattered Ultrasonic Pulses in Reactive Cast Metal–Matrix Composites

In this work, we study the influence of the local porosity in isotropic reactive cast particulate reinforced metal–matrix composites on the statistical amplitude distribution of backscattered broadband pulses of longitudinal ultrasonic waves. A special laser optoacoustic transducer is employed for this purpose, which makes it possible to achieve laser excitation and piezoelectric detection of ultrasound by one-side access to a sample or product. Two series of in-situ reactive cast aluminum–matrix composites were studied: reinforced solely with the Al3Ti intermetallic particles (volumetric contents 0.04–0.115) and with combination of Al3Ti and synthetic diamond nanoparticles (volumetric content 0.002). The last accelerate reactive synthesis of Al3Ti particles and lead to modification of their shape and sizes. For both series of composites, the amplitude distribution of backscattered ultrasonic pulses has been approximated with the Gaussian probability distribution applicable for statistics of large number of independent random variables. The empirical dependence of the half-width of this distribution on the local porosity in composites of two series has been fitted by the same function close to the linear one regardless the size and content of reinforcing particles. This functional relationship can be used for quantitative evaluation of the local porosity of the composite material both at its manufacturing stage and during service of composite parts and products.

Preparation, microstructure and tensile properties of two dimensional MXene reinforced copper matrix composites

The dispersion homogeneity of particles has a significant influence on the mechanical properties of particle reinforced metal matrix composites. In this study, a new Cu matrix composites with uniform dispersion of submicron and nanoscale MXene reinforcement particles were fabricated by the methods of high energy ball milling and hot pressing sintering. The microstructure evolution of MXene-Cu composite powders were studied in detail. When the initial MXene content is less than 3 vol%, the MXene particles can be dispersed homogenously in Cu matrix after 12 h ball milling. The refinement and dispersion of the MXene particles are mainly achieved by the cold welding and plastic deformation of composite particles in ball milling process. The XRD and TEM results reveal that these MXene reinforcement particles have been transformed to cubic TiC x in the final MXene/Cu composites. The tensile test results indicate that the UTS and elongation of the MXene/Cu composites are closely related to the dispersion homogeneity of the MXene particles. The UTS and elongation of the 1MXene/Cu and 3MXene/Cu composites increase with increasing the ball milling time. The UTS of the 3MXene/Cu-12 h can reach to 314 MPa with an elongation of 11.1%. The maximum UTS of the 5MXene/Cu-6 h can reach to 354 MPa. However, further increase in milling time would result in the UTS and elongation decline. The fracture surface analysis further testifies that the 3MXene/Cu-12 h composite presents a typical plastic fracture feature, while the 5MXene/Cu composite with various ball milling time all present brittle fracture characteristic for the severe agglomeration of MXene particles.

Significantly improved interfacial shear strength in graphene/copper nanocomposite via wrinkles and functionalization: A molecular dynamics study

Graphene reinforced metal matrix composites (MMCs) have received extensive research interests as promising structural materials in developing lightweight structures. The mechanical performance of such composites, however, is considerably hindered by weak van der Waal (vdW) interaction between graphene and metal matrix. The present work shows that this challenging issue can be effectively alleviated by the use of chemically functionalized graphene fillers with mechanically induced wrinkles. Our extensive molecular dynamics (MD) simulations on graphene reinforced copper (Cu) composite manifest that the presence of shear-induced wrinkles and chemical modification of graphene using functional groups can significantly increase its surface roughness, enhance the vdW interaction and consequently lead to higher interfacial shear strength (IFSS) between graphene and Cu matrix. Compared with its counterpart functionalized with hydrogen, graphene functionalized with alkyl (methyl, ethyl, propyl, and butyl) offers better interfacial interactions with Cu matrix because these functional groups are longer than hydrogen functional group and can be embedded deeper into the matrix.

Modeling of force and temperature in cutting of particle reinforced metal matrix composites considering particle effects

• An analytical force model for PRMMCs is established considering particle effects. • An analytical model of tool face temperature of PRMMCs is developed with particle effects. • Predictions considering particle effects accurately estimate experimental results. • Complex variations of force and temperature is strongly influenced by reinforced particles. Particle reinforced metal matrix composites (PRMMCs) machining is considerably difficult owing to the significant influence of hard particles on the force and temperature during cutting. To provide an insight for understanding the effect of particles on the force and temperature, this paper aimed at modeling of the force and temperature affected by reinforced particles in PRMMCs cutting. Firstly, an analytical force model of PRMMCs was established based on a dynamic constitutive model considering particle effects. The influences of hard particles on the shear strength in the shear zone were considered in the dynamic constitutive model, including particle strengthening effect and particle damage. The particle debonding and fracture near the cutting edge were additionally considered in the force model, based on an energy-based method. Then, an analytical model of tool face temperature with particle effects was developed by considering the characteristic of the heat generated in PRMMCs cutting. To predict force and temperature in PRMMCs cutting, a combined prediction method, which used an improved three-phase friction model, was proposed to integrate the force model with the temperature model. The predicted force and temperature in cutting of various PRMMCs under different cutting conditions were validated through a comparison with experimental results. The comparison results showed that the force and temperature predicted by the analytical models considering particle effects were found to be more accurate than the analytical models without considering particle effects. Finally, comprehensive investigation of the effect of reinforced particles on the cutting force and temperature was explored, based on the modeling of the force and temperature in PRMMCs cutting. The results indicated that the complex variation of forces with particle content and size mainly depended on the shear strength, which was strongly affected by particle damage. A decrease in tool face temperature with increasing particle content was caused by a reduction in the plastic shear energy of the metal matrix.

Research progress in molecular dynamics simulation of CNT and graphene reinforced metal matrix composites

Abstract Carbon nanomaterials are considered as one of the ideal choices for high-performance metal matrix composite reinforcements and one of the key directions of scientific research in recent years. Molecular dynamics simulation could be used conveniently to construct different composite material systems and study the properties of carbon nanomaterials reinforced metal matrix composites under different conditions. This review mainly introduces the molecular dynamic research progress of carbon nanotube (CNT) and graphene-reinforced metal (Cu, Al, Ni) composites. The potential functions of the carbon nanomaterials reinforced metal matrix composite simulation systems are briefly introduced. The dependence of the mechanical properties of metal matrix composites on the sizes, volume fraction and distribution states of CNT and graphene is detailed and discussed. Finally, we briefly summarize the future development direction of the molecular dynamic simulation with respect to carbon nanomaterials reinforced metal matrix composites.

Overcoming the strength-ductility trade-off of an aluminum matrix composite by novel core-shell structured reinforcing particulates

The trade-off between strength and ductility of particulate reinforced metal matrix composites (PRMMCs) has been a longstanding puzzle. Here we propose an effective strategy to surmount the inverse relationship between strength and ductility of an A356 Al alloy based PRMMC by in situ synthesizing novel reinforcing particulates with a special core-shell (CS) structure. Such structure features a Ti core inside a dual-layer shell: the inner layer has a nano-grained (~130 nm) heterogeneous structure, and the outer layer possesses a composite structure composed of a (Al,Si)3Ti substrate with dense dispersion of nanoparticles. As a result, the obtained composite reinforced with such CS reinforcing particulates (CS composite) achieves an unprecedented tensile elongation to failure of 8.3 ± 0.8% and a uniform elongation of 7.1 ± 0.6%, which nearly triples that of the same alloy based composite reinforced with monolithic (Al,Si)3Ti particulates (monolithic composite) and equivalent to corresponding matrix alloy while maintaining high ultimate tensile strength of 373 ± 8.8 MPa and yield strength of 268 ± 7.9 MPa, equivalent to monolithic composite simultaneously. This special architecture of shell renders itself a high capability of stress bearing and good toughness, and the nanoparticles in outer layer further slower crack development, which significantly postpone crack formation in shell. Subsequent propagation of cracks in Ti core is also constrained remarkably by the transformation-induced plasticity effect occurred ahead of crack tips resulting from stress-induced phase transformation of hcp-Ti into fcc-Ti. These factors lead to highest work hardening rate that undergoes a long plateau and thus overcome the strength-ductility trade-off of A356 alloy based PRMMC.

Electrochemical Discharge Grinding of Metal Matrix Composites Using Shaped Abrasive Tools Formed by Sintered Bronze/diamond

Abstract Electrochemical discharge machining (ECDM) is a well-known process for machining of particulate reinforced metal matrix composites (MMCs). However, ECDM process suffers several drawbacks such as the lower material removal rate (MRR), high risks of tool wear rate (TWR) and relatively poor surface quality, etc. This study proposes a kind of electrochemical discharge grinding machining (ECDGM) method which employs a special shaped tool electrode. During the process, not only the can the hybrid action of electrochemical dissolution, spark erosion, and abrasive grinding improve the performance of machining MMCs, but also the special shaped of the tool electrode can be used to discharge the machined debris. And thus a higher machining efficiency and lower TWR can be obtained. The performance of developed process was conducted on machining of SiC particulate reinforced aluminum workpiece. The role of peak curre+nt, pulse duration, duty cycle, rotary speed and abrasive grit size has been investigated on MMR and TWR using the nonabrasive round electrode, abrasive round electrode, and abrasive shaped electrode respectively. The experimental results showed that using the shaped abrasive electrode for machining MMCs can achieve a higher MRR and lower TWR, as compared to the non-abrasive round electrode, abrasive round electrode. Besides, the orthogonal method was employed to analyze the relative importance of the machining parameters on MRR and TWR, it has been observed that MRR is affected by the processing parameters following the order of rotary speed > peak current > duty cycle > pulse duration, and TWR is following the order of peak current > duty cycle > pulse duration > rotary speed.

Effect on the Mechanical Properties of Al 7075 Reinforced with SiC and TiC Particles

In the present industrial scenario, Aluminium and its alloy based composites have more importance in the growing fields of engineering. Aluminium reinforced metal matrix composites are broadly speaking desired because it has the excessive strenth along with less weight, hardness, corrosion resistance, fatigue and creep resistance. The Al composites are focused to use in aerospace, automobile and also in structural domain because it gives good strength with less weight. This paper discussed about the mechanical residences of Aluminium 7075 alloy strengthened with SiC and TiC. Stir casting process was utilized for fabrication of composites and composite specimens are subjected to tensile test by using Universal Testing Machine. The composite hardness was tested by using Brinell hardness tester and the Charpy impact tester used for findings the impact strength. An experimental results are compared with unreinforced alloy of Al 7075. Micro structural characterization confirms the particles of reinforcement are distributed to the entire structure of matrix. The experimental result shows the mechanical properties slightly increased by varying wt% of reinforcements in the matrix material. The better tensile strength (252MPa), hardness (83HB) and impact strength (4.6 Joules) is obtained by the composition of 60% wt of Al 7075, 20% wt of TiC and 20 %wt of SiC.

Microstructural, Dynamic and Residual Stress Analysis of Metal Matrix Composite Shafts

Metal matrix shafts are widely used in industries, and various research works are available for the characterization and applications of these components. These research works are limited to the conventional characterization of the material. In this paper, a novel characterization approach has been adopted, which determines the effect of reinforcements on the dynamic properties and residual stress of the Al 6061/Al2O3 shafts. Long and slender shafts were fabricated through a stir casting process. Grain structure was obtained through optical microscopy, and morphological evaluation of the composites was performed through scanning electron microscopy. In addition, X-ray diffraction patterns were analysed, and residual stress was calculated by X-ray residual stress measurement system μ-X360 Ver. 2.3.0.1. Tensile residual stress was observed for pure Al 6061 alloy shaft on the surface of shafts, whereas compressive residual stress was observed in the case of composite shafts. The magnitude of the compressive residual stress increased with the increased wt% of alumina in the Al 6061 matrix. The amplitudes of vibration were also reduced by the introduction of reinforcements in metal matrix composites.

Sintering and Dimensional Analysis of Cu/CNTs via a Powder Metallurgy Route

Recently, carbon nanotubes (CNTs) reinforced metal matrix composites (MMCs) have attracted an increasing interest, due to their promising properties such as high Young’s modulus and tensile strength. CNTs are considered to be an attractive reinforcement material for lightweight and high-strength metallic matrix composites. When powder metallurgy (PM) is used to form these MMCs (such as Cu/CNTs composites), the sintering parameters are crucial in obtaining good final parts. This work attempts to investigate the effect of sintering parameters on physical properties in these MMCs. The process comprised of mixing of Cu powder with CNTs, compacting of the powder mixture to form green parts and sintering using a quartz tube furnace under argon atmosphere. In this study, four trials of heating rate were performed and evaluated before sintering process was conducted. Finally, the green body was initially heated isothermally at 100°C for 1 hour with heating rate of 1.0 °C/min and sintered at a temperature of 900°C for 2 hours with heating rate of 0.5 °C/min. The composites contained 0 to 4 vol% of pristine CNTs (PCNTs) and acid treatment CNTs (ACNTs), respectively. It was observed that as the CNTs content increased, the density of the composites was also decreased owing to low density of the CNTs. The sintered part in this present work has undergone volume shrinkage ranging from 12.41% to 17.02% and 13.36% to 19.30%, for Cu/PCNTs and Cu/ACNTs respectively. It was found that the heating rate played an important role in producing a good sintered part. A high heating rate induced large thermal stress and possibly increased the pore volume, leading to swelling. As part of the temperature sensitivity, the heating rate was useful in controlling microstructure evolution in sintering. A correlation between the volume shrinkage, density and porosity of the good sintered part was confirmed in this work.

Jump ablation-based improvement of nanosecond laser processing of SiCp/AA2024 composites

Ceramic particulate reinforced metal matrix composites is a promising material, but it is difficult to be machined. Pulsed laser processing as a advanced technique is widely used in material processing, but the pulsed laser processing of particulate reinforced metal matrix composites is not sufficiently studied. In this work, scanning ablation of SiC particulate reinforced aluminum metal matrix (SiCp/AA2024) composites was conducted using a nanosecond laser. An innovative jump ablation method was proposed, and the composites processing by jump ablation and common ablation were compared. Both plasma’s and nanosecond laser ablation mechanism’s effects on ablation were analyzed. In contrast to common ablation, jump ablation can effectively increase the ablation depth and rate. At an SOR of 95%, the ablation depth was 39 μm and 99 μm in common and jump ablation respectively, and the increasement was nearly 150%. Meanwhile, The matrix and reinforcement phases on the composites’ ablated surface after jump ablation exhibited relatively independent distribution, while the recast layer was thinner and less oxidized than that produced by common ablation.

Analysis of Power Consumption in the drilling of Nano SiC reinforced Aluminium matrix composites

Nanoceramic particles reinforced Metal Matrix Composites (MMNC) have gained immense attention from both the scientific and industrial community. The employment of these advanced class materials in the industries has given many advantages. These Nanocomposites are very difficult to machine, and the number of holes is to be drilled on their surface for many applications as drilling is considered as one of the significant applications in the industry. The researchers and industrial experts are striving very hard to attain green manufacturing techniques in drilling, which creates less impact on the environment and consume lower power. The main aim of current research is to analyse the power consumption in the drilling of Nano silicon carbide (SiC) reinforced Aluminium (Al) matrix composite under various machining conditions, cutting speeds, feed rates. For this purpose, a series of experiments have been planned using Taguchi’s L18 orthogonal array. The drilling tests were performed using a vertical machining centre (VMC) which is controlled by computer numeric control (CNC) employing carbide drills of 10mm dia with cutting point angles of 90°, 118° and 135°. The machining operation is performed under Dry cutting and Cryogenic cutting condition. On successful completion of the experiments, the surface morphology is studied using Field Emission Scanning Electron Microscopy (FESEM).

Applying visualization techniques to study the fluid flow pattern and the particle distribution in the casting of metal matrix composites

Abstract For a past few decades, metal matrix composite has a significant role in the various industrial and automobile applications. Production of metal matrix composite using stir casting technique is one of the most effective and economical technique. Achieving the uniform distribution of the reinforced particles was the major problem facing during the production of particle reinforced metal matrix composites and also achieving the effective fluid flow pattern was the greatest challenge to the research community. In this research, some of the major stir casting process parameters such as blade geometry, stirring speed and impeller position were optimized based on the vortex height of the fluid and settling time of the reinforced particles using visualization experiments and Grey relation analysis. Flow pattern of the fluid and the trace of the particles was analysed using a new technique called streak photography. Streak photography was one of the visualization experiments using glycerol water based model. Al8011/SiC metal matrix composites were manufactured based on the optimized stir casting process parameters. Finally, the fabricated composites were carried out for OM, SEM analysis and Brinell hardness testing for confirming the uniform distribution of the reinforced particles. Based on the confirmation results, 45ᴼ stirrer blade angle, impeller position 40 % from the base and 250 rpm stirring help to produce uniform distribution of the particles.

Investigation on surface roughness, residual stress and fatigue property of milling in-situ TiB2/7050Al metal matrix composites

For higher efficiency and precision manufacturing, more and more attentions are focused on the surface roughness and residual stress of machined parts to obtain a good fatigue life. At present, the in-situ TiB2/7050Al metal matrix composites are widely researched due to its attractive properties such as low density, good wear resistance and improved strength. It is of great significance to investigate the machined surface roughness, residual stress and fatigue life for higher efficiency and precision manufacturing of this new kind material. In this study, the surface roughness including two-dimensional and three-dimensional roughness, residual stress and fatigue life of milling in-situ TiB2/7050Al metal matrix composites were analyzed. It was found from comparative investigation that the three-dimensional surface roughness would be more appropriate to represent the machined surface profile of milling particle reinforced metal matrix composites. The cutting temperature played a great role on the residual stress. However, the effect of increasing cutting force could slow down the transformation from compressive stress to tensile stress under 270 °C. An exponential relationship between three-dimensional roughness and fatigue life was established and the main fracture mechanism was brittle fracture with observation of obvious shellfish veins, river pattern veins and wave shaped veins in fracture surface.

High strength-ductility synergy of MgAlB4 whisker reinforced aluminum matrix composites achieved by in situ synthesis

For ceramic reinforced metal matrix composites, it is a critical issue to improve the limited ductility to achieve a combination of high strength and high toughness. Herein, in-situ synthesized MgAlB4 whisker reinforced Al (MgAlB4w/Al) composites with rational distribution of the reinforcement were successfully prepared by an efficient process combining vacuum pressureless sintering and hot-extrusion. The results demonstrate that the MgAlB4 whiskers noticeably coarsen with increasing sintering temperature, while the sintering duration has little effect on the size of the whiskers. The as-extruded composite with 15 wt% MgAlB4w has excellent comprehensive properties with the ultimate tensile strength of 380 MPa and the fracture elongation of ~9.6%. Fracture analysis reveals that the whiskers bear most loads and fracture firstly to form crack sources with the load increasing during drawing. In addition, the alignment distribution of MgAlB4w along extrusion direction is the main reason for the improved ductility of the MgAlB4w/Al composite.

Fiber reinforced metal matrix composites - a review

Modern technology has placed increasing demands on materials. The need of hour is to develop the new materials so as to overcome the limitations of the materials existed presently regarding applications in different fields. The materials with properties such as better wear resistance, high specific strength and stability at high temperatures have been in great demand in the past few decades. The properties of conventional materials can be improved by the method of reinforcing whiskers, fibers and particles in to polymers, metals and ceramics. This has resulted in the manufacturing of composite materials. The mechanical properties of fiber reinforced metal matrix composites (MMCs) make them the suitable choice for applications in the fields of automotive and aerospace etc. The paper outlines the overview of fiber reinforced MMCs. The applications, manufacturing methods and mechanical properties of these composites are discussed. Furthermore, this review describes the single fiber push-out test which is developed in the past years so as to measure quantitatively the properties of the interface between the fiber and the matrix in these fiber reinforced MMCs.

Mechanical and microstructural analysis of Al-Al2O3/B4C hybrid composites

The present work aims to enhance the mechanical performance of monolithic Al alloy and single reinforced metal matrix composite using a hybridization technique. The microparticles of alumina and boron carbide were reinforced into cast Al alloy (6061) in a systematic varying ratio (i.e.100/0, 75/25, 50/50, 25/75 and 0/100) to prepare the hybrid metal matrix composites via stir casting method. The mechanical properties (i.e. tensile, impact, hardness and flexural) of the prepared composites were investigated as per ASTM standards. Furthermore, microstructural analysis of unfractured and fractured composite samples was also carried out using Scanning Electron Microscope. It was observed that hybrid composites comprising of microparticles revealed an enhanced tensile, flexural and hardness properties, and reduced impact energy and porosity as compared to Al alloy and single reinforced metal matrix composites. The highest values of tensile strength and modulus were offered by a hybrid composite (B50A50), which was 40% and 52.12% higher than that of Al alloy. Furthermore, there was an improvement of 105.72% in flexural strength and a reduction of 23.88% in impact energy for composite B50A50 than that of Al alloy. The present developed hybrid metal matrix composites can be proposed to be used in automobile parts and construction applications.

Effect of heat treatment on the microstructure and properties of in-situ Mg2Si reinforced hypereutectic Al-18%Si matrix composites

The in situ preparation of particle reinforced metal matrix composites (PRMMCs) can prevent the particle surface from pollution, improve the wettability of particles and matrix metals, and reduce the production cost of composites. In this paper, in situ Mg2Si reinforced hypereutectic Al-18%Si matrix composites were prepared by adding an appropriate amount of magnesium. However, the Mg2Si enhanced phase often has developed dendrites, which are easy to cause stress concentration and cut apart the matrix, resulting in the decrease of the mechanical properties of the material. Therefore, in this study, necessary solution treatment and aging treatment were carried out, and the effect of heat treatment on the microstructure and properties of the prepared composites was discussed. The results showed that the in situ Mg2Si reinforced Al-18%Si matrix composites with an ideal microstructure could be prepared by adding 4% Mg. After solution treatment at 545 °C for 8 h and aging treatment at 170 ± 2 °C for 8 h, the coarse dendrites of Mg2Si were broke and granulated, which improved the strength, hardness and wear resistance of the composites. Compared with the common as cast hypereutectic Al-18%Si alloy, the hardness and the strength of the prepared composites were increased by 30% and 46%, respectively. Besides, the granulation process of the in situ Mg2Si phase was explained with the Gibbs-Thomson theorem in this paper.