Fabrication Of Metal Matrix Composites Research Articles

Optimization of friction stir processing parameters for enhanced microhardness of AA5083/Al-Fe in-situ composites via Taguchi technique

Friction stir processing (FSP) is a novel technique to fabricate metal matrix composites (MMCs) and surface composites (SCs). In the present study, Taguchi’s technique is used for attaining the optimum value of microhardness for AA5083/Al-Fe in-situ surface composites (SCs) via FSP using 40 hours mechanical alloyed Fe-40wt% Al powder mixture. Three different process parameters i.e. tool shoulder diameter, tool rotational speed, and tool traverse speed each having three levels were selected for optimizing the microhardness of SCs. The experimental study was accomplished by employing Taguchi's L9 orthogonal array. The Microhardness of the fabricated composites was confirmed using Vickers tester after the single-pass FSP. The outcomes of the study were examined and studied using signal to noise (S/N) ratio. The analysis also confirms the results and displayed that the optimum value of microhardness of 123.3 Hv was obtained with the selected parameter of tool shoulder diameter of 21 mm, tool rotational speed of 900 rpm, and traverse speed of 63 mm/min.

Synergetic enhancement of strength and ductility for titanium-based composites reinforced with nickel metallized multi-walled carbon nanotubes

Poor ductility of titanium matrix composites with medium/high-strength reinforced with carbonaceous nanomaterials (eg., graphene, carbon nanotubes etc.), has seriously restricted their wide-range engineering and practical industry utility. Herein, we propose a new methodology to significantly and simultaneously enhance both ductility and tensile strength of the titanium matrix composites. We ball milled Ti–6Al–4V (TC4) powders with in-situ chemically synthetized Ni decorated multi-walled carbon nanotubes (i.e MWCNTs@Ni), and then sintered the composites powders using spark plasma sintering (SPS). We achieved both a significant balanced between superior strength and increased ductility of the composite using the MWCNTs@Ni nanopowders. The enhanced strength in composites is mainly attributed to the interfacial structures for effectively enhanced load transfer capability between MWCNTs@Ni and Ti matrix, e.g., the formation of coherent/semi-coherent interfaces among interfacial phases Ti2Ni, TiC and Ti matrix. Furthermore, we applied the dislocation theory to reveal the toughening mechanisms of MWCNTs@Ni in the MWCNTs@Ni/TC4 composites. This study provides a new methodology of fabricating metal matrix composites (reinforced with carbon based nanomaterial) with both high strength and good ductility.

Effect of annealing treatment on microstructure and mechanical properties of cold sprayed TiB2/AlSi10Mg composites

Cold spray allows for fabricating metal matrix composites or repairing damaged components in a scalable way with a high deposition rate. Nevertheless, the poorly bonded interfaces (both metallic splats/splats and metallic splats/reinforcements) and pores in the composite deposit result in undesirable mechanical performance, which limits its applications for load-bearing components. In this study, a special designed composite powder reinforced with in-situ TiB2 particles was used as the feedstock to produce TiB2/AlSi10Mg composite components by cold spray additive manufacturing. Following this, the effect of post-annealing treatment on interfaces and micro-pores healing, microstructure evolution, and mechanical properties of the cold sprayed TiB2/AlSi10Mg composites was investigated in terms of X-ray diffraction, electron backscatter diffraction, transmission electron microscopy, and tensile test. The cold sprayed composite exhibited a bimodal structure with ultrafine grains formed at the inter-splat boundaries due to dynamic recrystallization induced by intensive plastic deformation of the particles. In addition to the uniformly dispersed TiB2 nanoparticles, some aggregated clusters remained embedded in the Al matrix. Tensile tests revealed that the as-sprayed deposits possessed very high tensile strength but almost no toughness due to the poorly bonded inter-splats and enhanced work hardening effect. Significant improvement in ductility was achieved in the annealed samples through improvement of metallurgical bonding between the deformed splats, release of residual stress, and static recrystallization. Interestingly, when the annealing temperature was increased up to 500 °C, both the pure AlSi10Mg and TiB2/AlSi10Mg composite samples fractured at a very early stage due to the presence of large pores (>20 µm) which may originate from the moisture of initial powders. The in-situ formed TiB2 nanoparticles play an important role in strengthening the Al matrix, meanwhile, maintaining a good ductility due to the robust interface bonding. This study demonstrates the potential of using a gas-atomized composite powder to produce high-performance metal matrix composites by cold spray additive manufacturing followed by annealing treatment.

Laser powder bed fusion of high-entropy alloy particle-reinforced stainless steel with enhanced strength, ductility, and corrosion resistance

In additive manufacturing of metal matrix composites, it is difficult to ensure high strength as well as high ductility simultaneously. In this study, a FeCoNiCr high-entropy alloy was used as the strengthening phase to improve the performance of austenitic stainless steel processed via laser powder bed fusion. The microstructure of the as-printed parts was composed of high-entropy alloy nanoparticles, a solid solution matrix, and high-density dislocations. The strengthening effect caused by the microstructures resulted in a tensile strength of 627 MPa with a maximum elongation of 50%. The semi-obstructive effect of the interface on the dislocations improved the ductility, as proved through molecular dynamics analysis. The Cr, Ni, and Co elements in the high-entropy alloy melted into the stainless-steel matrix, facilitating the formation of a passive film; this improved the corrosion resistance of the composite. Thus, simultaneous improvements in strength, ductility, and corrosion resistance of the stainless-steel composites were realized. The composites inherited the performance characteristics of high-entropy alloys. This research also provides a new strategy to select the strengthening phase for composite materials. High-performance high-entropy alloy particles with lattice structures and element types similar to the stainless steel matrix have substantial potential to be used as strengthening phases.

Effect of Zener-Hollomon Parameter on Microstructure of Aluminum Based Nanocomposite Layers Produced by Friction Stir Processing

For more than a decade, there has been considerable interest in the fabrication of metal matrix composites by employing Friction Stir Processing (FSP). In this study a new model based on Zener-Hollomon (Z) parameter has been developed, which is believed to be the first of its kind, to accurately predict microstructural characteristics of Al-based composites Additionally, the processing window of composite fabrication determined and revealed that sound samples achieve within the range of 2.42 to 24.61 rev/mm for the ratio of rotation speed to travel speed (ω/ν). Recording the peak temperatures during processing beside the optical and Scanning Electron Microscopic (SEM) studies showed that increasing the number of FSP passes and the ratio of ω/ν have a remarkable influence on bolstering the role of nanoparticles in grain refinement. Results also indicated that the mean grain size of FSPed samples and matrix of nanocomposites decreases with an increase in the Z parameter. Finally, particular equations for various numbers of passes developed, which make a correlation between the grain size of Al-based composites and the FSP parameters via Z parameter.

Synchrotron X-ray diffraction studies of the phase-specific deformation in additively manufactured Ni–CrC composites

Cold spray is a promising solid-state additive manufacturing process for the fabrication of metal matrix composites in the forms of coatings, and more recently, bulk materials, particularly when deposition of two phases is needed with minimal alterations of the chemistry and phase composition. While prior studies have reported improved mechanical performance in cold sprayed composites, a fundamental understanding of the response and contribution of individual constituent phases to the collective mechanical properties of the composite is yet to be developed. In this work, we use in-situ synchrotron X-ray diffraction to study the strain partitioning between the soft and hard phases in cold sprayed Ni–CrC bulk composites. We conduct stepwise uniaxial tensile loading experiments and use high energy X-ray diffraction at multiple load steps to measure phase-specific strains and stresses upon loading. We find neither plasticity in the Ni phase nor a significant load transfer or redistribution between Ni and CrC phases during the loading process and attribute them to a premature failure governed by the presence of defects.

Manufacturing of B4C particle reinforced A360 aluminium cellular composite materials by the integration of stir casting and space holder methods

Stir casting method has become prominent for fabrication of metal matrix composites in recent years. This method can be adjusted for casting around space holding particles to obtain cellular composite materials. In this study, a specific method which is a combination of stir casting and space holder techniques were used to produce open-celled A360 aluminium-B4C composite foams with regular sized and distributed pores. Weight ratios of reinforcement particles determined as 0.5, 1, 1.5 and 2%. The influences of particle reinforcement on the microstructure and the mechanical behaviour of composite foams were investigated. Microstructures were analysed with optical microscope (OM), scanning electron microscope (SEM). Compression and hardness tests were carried out to observe the effects of reinforcement on mechanical properties. Compression strength properties and hardness of composites increased with the ceramic reinforcement, however the plastic strength of the composite foams showed worsening trend after a certain reinforcement ratio (0.5 wt.%). Energy absorption properties of the composite foams showed parallel trends with compressive strength properties.

Experimental investigation on stir casting of a metal matrix composite material

In this article, Al7075 matrix with SiC as reinforcement particle was developed and the mechanical properties such as tensile strength, hardness, and impact strength was investigated. Aluminum is preferred as a matrix phase because Al alloys have low density and good ductility. Silicon carbide is chosen as a reinforcement phase due to its brittle and hard properties to enhance the wear properties. Mechanical properties of aluminum metal matrix have been tested at different temperatures and holding time. It shows an ultimate tensile strength of 121 N/mm2 at 800°C processing temperature and 20 mins of holding time. At a processing temperature of 850°C, it shows maximum hardness and impact strength. Among all the fabrication processes, stir casting is chosen because stir casting process is the simplest and cheapest for fabricating metal matrix composites (MMCs). Microelectronic and aerospace packaging industry requires a material with optimum hardness and impact strength to prevent the material from wear and impact during material handling. These MMCs will be a replacement for traditionally used materials such as W-Cu, BeO, and Kovar in packaging application.

Effect of MnSi2‐Induced Solid Solution Strengthening on Mechanical Behavior of 316L Stainless Steel Fabricated by Selective Laser Melting

As an emerging additive manufacturing technology, selective laser melting (SLM) can manufacture metal matrix composites with high performance. Herein, a MnSi2 compound is innovatively utilized to improve the mechanical properties of the 316L substrate. The results indicate that an appropriate mass fraction of the MnSi2 compound can promote the solid solution, leading to an increment in the surface quality, microhardness, and tensile strength of the 316L substrate. When the addition of MnSi2 is 6.0 wt%, the sample exhibits the highest microhardness and tensile strength with the value of 426 HV0.2 and 860 MPa, respectively. However, microcracks are observed and the ultimate tensile displacement is decreased synchronously; meanwhile, its fracture behavior exhibits mixed‐mode ductile fracture and brittle fracture. Overall, this study explains a novel hypothetical mechanism of solid solution reinforcement by adding a MnSi2 compound into 316L.

Fabrication of AA2024/SiCp Metal Matrix Composite by Mechanical Alloying

Mechanical alloying is a widely used alternative to the liquid-phase method of embedding reinforcements to manufacture metal matrix composites (MMC). In this research, high-energy ball milling was used to distribute various volume fractions of sub-micron-sized SiCp particles (2, 10, and 20 vol%) in AA2024 aluminum powder alloy, focusing on powder morphology and milling conditions. An increase in the full width at half-maximum and the shifting of peaks at higher angles were observed after mechanical alloying. These examinations were attributed to changes in the lattice parameters of the matrix alloy. It was noted that the temperature and loading pressure during the die compaction stages of MMC powders directly affect the compact density, whereas the volume fraction of SiCp changes hardness. Compression testing, conducted at elevated temperatures to evaluate the plastic properties of the material, showed sufficient ductility characteristics for thermomechanical processing.

Recent progress of CNTs reinforcement with metal matrix composites using friction stir processing

Friction Stir Processing (FSP) is a proven technique for the fabrication of Metal Matrix Composites. It is shined in these recent years for its enormously improving capabilities of surfaces of different materials. As Carbon Nanotubes (CNTs) hold excellent mechanical, thermal, and electrical traits, they have become a boon as reinforcements to improve the properties of the materials. Reinforcing CNTs into the materials using FSP exceptionally increases the properties of different materials. This article reviews the CNT's reinforcement with metals such as Aluminum, Magnesium, Copper, and few other alloys by exploring the latest tendencies and techniques employed to manufacture the particulate metal matrix composites, to improve friction stir process efficiency. Moreover, notable microstructural features and mechanical properties are also discussed. The article concludes with the conclusion drawn from the literature and future work that needs consideration is also mentioned.

Development and evaluation of polyvinyl alcohol films reinforced with carbon nanotubes and alumina for manufacturing hybrid metal matrix composites by the sandwich technique

<abstract> Metal matrix composites (MMCs) have been a fundamental element in the development of technologies related to the aerospace and automotive industries. This is because they have an excellent weight-to-strength ratio, i.e., they are light materials with a high mechanical resistance. In the manufacturing of MMCs, the incorporation and homogeneous dispersion of reinforcements in the matrix has been one of the biggest challenges. The issue has expanded to the manufacturing of materials reinforced with nano-scaled particles. This study is aimed at the manufacturing, optimization, and characterization of the polymeric matrix reinforced with carbon nanotubes and alumina (hybrid composites), in order to use the polymeric matrix as an inclusion vehicle of the nano-reinforcements in a metallic matrix. The synthesis of the polymeric matrix composites was carried out by a solution mixing technique using polyvinyl alcohol as a matrix. For the reinforcement's dispersion, a magnetic stirring and sonication were used. Finally, the solution was put into a petri dish to allow its polymerization. The nano-reinforcement dispersion qualification and the quantification of the polymer matrix composite were carried out through the tension, nanoindentation, dynamical mechanical analysis test, elastic modulus mapping, and statistical model for dispersion. In addition, a preliminary study of the metallic composite was carried out and was fabricated by the sandwich technique. The initial characterization of the composites was performed through the nanoindentation test. </abstract>

ПОЛУЧЕНИЕ МЕТАЛЛОМАТРИЧНЫХ КОМПОЗИТОВ НА ОСНОВЕ СПЛАВА ВЖ159 МЕТОДОМ СЕЛЕКТИВНОГО ЛАЗЕРНОГО СПЛАВЛЕНИЯ

The paper considers manufacturing of metal matrix composites (MMC) by means of selective laser melting. The heat-resistant nickel-based Ni–Cr–Mo–Nb–Al alloy was chosen as a matrix material, the Y2O3 oxide was chosen as a strengthener. After mechanical alloying the obtained powder was used in SLM for the production of a material. The synthesized material’s condition was examined after the SLM process and after hot isostatic pressing (HIP). In the structure the areas containing Y, Al and O-based compounds were found. The creep-rupture tests of samples after HIP and heat treatment were performed and the results were explained by fractographic analysis.

Behaviour of Al2O3 in aluminium matrix composites: An overview

In this paper, behaviour of Al2O3 in aluminium matrix composites is reviewed for its properties and applications. In addition, many metal matrix composite fabrication processes are also elaborated. In the present days the aluminium metal matrix composite is in high demand because of its superior properties. Its demand is still on rise because of its widespread use in automotive industries, aerospace industries and marine industries. The method of the fabrication of aluminium matrix-based composite is also a deciding factor for its resultant properties. Desired composite-properties are achievable by proper selection of reinforcing materials as well as the physical conditions. Various sections of current information compile the details about the behaviour of alumina particles in aluminium-based matrix for formation of metal matrix composites.

Hydrodynamic analysis of different impellers used in the stir casting process

In this work, the hydrodynamic behavior of four types of impellers used in the manufacture of metal matrix composites (MMC) through the stir casting process is analyzed, in order to determine which of them is adequate to generate a uniform flow in the metal. Liquid and thereby achieve a uniform distribution of reinforcing particles. The impellers analyzed are the belt type, the vane type, the propeller type and the turbine type. As a first part, the parameters of each one of them were determined to later carry out the modeling in SolidWorks. Some properties of liquid aluminum were also determined, such as density and viscosity for a melting temperature. These characteristics were assigned in the software used. As results, the flow velocities and turbulences that occur with each impeller were obtained, being the propeller-type impeller the one that shows a more uniform distribution in terms of velocities.

Effect of Powder Metallurgy Process and its Parameters on the Mechanical and Electrical Properties of Copper-Based Materials: Literature Review

As the world is shifting towards renewable sources of energy, the demand for copper is increasing due to its excellent electrical and corrosion resistance properties. Although, because of low strength and wear resistance, the use of pure copper is quite limited. Various reinforcing materials are added to the Cu matrix to fabricate high-strength and wear-resistant copper matrix composites. Powder metallurgy is the most commonly used metal matrix composite fabrication method for Cu-based materials. Properties of a powder metallurgy product depend on the process parameters such as compaction pressure, sintering temperature, sintering time, type and rate of reinforcement, size of matrix and reinforcing elements, etc. In the present work, the influence of the above-mentioned parameters on mechanical and electrical properties of copper-based materials produced by the powder metallurgy method is reviewed in detail. The literature survey revealed that SiC, graphite (Gr), TiC, and graphene (Gn) are the most commonly used reinforcement additives in the Cu matrix for improvement of the strength and wear resistance of Cu-based materials. It has been established that the strength and wear resistance increase after the addition of the mentioned reinforcers, although the electrical conductivity decreases. For enhanced mechanical and electrical properties, a 4–6% weight fraction of micron-sized reinforcers, such as SiC, TiC, and graphite, and a 0.25–1% weight fraction of nano-sized reinforcers, such as CNTs and graphene, are considered the optimum reinforcement range for the Cu-matrix. Small particle size of 3–5 μm of matrix material (Cu) improves mechanical and electrical properties. The size of nano-reinforcers, such as CNTs, should be sufficiently larger (30–50 nm) to avoid agglomeration. Besides, factors contributing to better properties are the optimum range of compaction pressure of 550–650 MPa, sintering temperature of 800–900°C, and sintering time of 60–90 min.

A Review of the Mechanical and Tribological Behavior of Cold Spray Metal Matrix Composites

Cold spray is an effective solid-state process for the fabrication of metal matrix composites where metallic, ceramic, or intermetallic reinforcements are embedded in a metallic matrix. Cold-sprayed metal matrix composites (CS MMCs) enable combining favorable properties of their constituent phases. Combinations of the ductility of metals with the high strength of ceramics or with the creep resistance of intermetallics are two typical examples. Here, we review recent advances in the understanding of the mechanical and tribological behavior of CS MMCs, with particular emphasis on the physical mechanisms and predictive understanding. We start the review with deposition mechanisms, defects, and microstructural features in CS MMCs. We continue the discussion with the mechanical behavior of CS MMCs, including elastic modulus, hardness, strength, ductility, as well as adhesive and cohesive failures. We also explore various aspects of the tribology of CS MMCs, from frictional response to abrasive and erosive wear. We discuss the effect of cold spray parameters and post-spray thermal and mechanical treatments on the microstructure and properties of CS MMCs. We connect experimental findings on the mechanics and tribology of CS MMCs with theoretical frameworks to the extent possible. Finally, we propose several critical unresolved issues in the field as future research directions.

Effect of Graphene nanoparticles on microstructural and mechanical properties of aluminum based nanocomposites fabricated by stir casting

Purpose The development of a new class of engineering materials is the current demand for aircraft and automobile companies. In this context metal, composite materials have a widespread application in different areas of manufacturing sectors. Design/methodology/approach In this paper, an attempt is made to develop the aluminium-based nano metal matrix composite reinforced with graphene nanoparticles (GNP) by using the stir casting method. Different weight percentage (0.4%, 0.8% and 1.2% by weight) of GNPs are used to fabricate metal matrix composites (MMCs). The developed nanocomposites were further validated by density calculation and optical microstructures to discuss the distribution of GNPs. The tensile test was conducted to determine the strength of the developed MMCs and also supported by fractographic analysis. In addition to it, the Rockwell hardness test and impact test (toughness) with fracture analysis were also conducted to strengthen the present work. Findings The results reveal the uniform distribution of GNPs into the matrix material. The yield strength and ultimate tensile strength obtained a maximum value of 155.67 MPa and 170.28 MPa, respectively. The hardness value (HRB) is significantly increased and 84 HRB was obtained for the sample with AA1100/0.4% GNP, while maximum hardness value (94 HRB) was obtained for the sample AA1100/1.2% GNP. The maximum value of toughness 14.3 Jules/cm2 is recorded for base alloy AA1100 while increasing the reinforcement percentage, it decreases up to 9.7 Jules/cm2 for AA1100/1.2% GNP. Originality/value Graphene nanoparticles are used to develop nanocomposites, which is one of the suitable alternatives for heavy engineering materials such as steels and cast irons. It has improved microstructural and mechanical properties which makes it preferable for many engineering and structural applications.

Achieving simultaneously improved tensile strength and ductility of a nano-TiB2/AlSi10Mg composite produced by cold spray additive manufacturing

The premature failure of components due to poor inter-particle bonding is the most critical issue in cold spray (CS) additive manufacturing. Herein, a hybrid strategy combining gas-atomization (involving in-situ reaction), CS, and post-friction stir processing was proposed to design a nano-TiB2/AlSi10Mg composite. Multiscale characterization in terms of X-ray diffraction and scanning and transmission electron microscopy was conducted to track microstructure evolution for better understanding the mechanisms determining mechanical performance of the produced composites. The results showed simultaneous improvement in both ultimate tensile strength (365 ± 35 MPa) and ductility (16.0 ± 1.2%), which represents a breakthrough. The strengthening and toughing mechanisms were attributed to the fine matrix grains with the significantly improved metallurgical inter-particle bonding, and the uniformly distributed TiB2 nanoparticles as reinforcement that was strongly bonded with the matrix (i.e. the formation of semi-coherent TiB2/Al interface). This study provides new guidance for hybrid additive manufacturing of metal matrix composites with high performance.

Study on the Effect of Volume Fraction (Vf%) SiC Addition to The Characteristics of Mg-Al-Sr / SiC Composites Using Stir Casting Method

In this study a magnesium metal matrix composite fabrication process was carried out combined with Al-15Sr alloy which will create intermetallic phases of Mg17Al12 and Mg58Al38Sr4. Reinforce material that is used for this study is SiC with an amount of 2, 4, 6, 8 vf%. Stir casting is used as the fabrication method as it doesn’t require much maintenance and relatively cheap. Argon is used as a shielding gas so oxidation does not occur to magnesium and prevent combustion. The composite is then casted into a SKD 61 metal mold and then cooled so it can be characterized by the various tests it will go through. SiC is added as the reinforcement material in hopes to increase the mechanical properties of the composite. This can be seen when the composite go through a number of tests, including microstructure analysis, SEM, XRD testing, and various mechanical tests. Through this procedure is it then concluded that composite with 6 vf% SiC is the optimum amount of reinforce material which results in UTS of 51,09 MPa, hardness of 73 HRH, impact strength of 0.0367 J/mm2 and abrasion rate of 5.68 x 10−3 mm3/m.