Aluminum Matrix Composite Materials Research Articles

Modification of cast aluminum matrix composite materials with barium

Modification of cast aluminum matrix composite materials with barium

Sustainability in the Manufacturing of Eco-Friendly Aluminum Matrix Composite Materials

The purpose of this work was to consolidate the eco-friendly Al–SiC composites prepared with various weight fractions of ceramic particles (0; 2.5; 5; 10; 15 wt.% SiC) in the energy-saving sintering process under vacuum and in a nitrogen atmosphere at 600 °C. The density of the manufactured composites was determined using Archimedes’ method. The mechanical properties and strength characteristics of the metal–ceramic interface were measured using three-point flexural and uniaxial compression tests, as well as the Brinell hardness measurement. The tribological properties were evaluated by determining the coefficients of friction and weight losses of the tested materials and identifying the tribological wear mechanisms. Advanced microstructural observation methods, such as scanning electron microscopy (SEM) and transmission electron microscopy (TEM), were used to analyze the microstructure of the composites in detail, including the identification of the phase composition using X-ray analysis methods. Low-cost composites with a porosity not exceeding 7% were successfully produced via energy-saving production routes. Simultaneously, owing to the formation of aluminum nitrides during sintering in a nitrogen atmosphere, these composites exhibited mechanical and tribological properties superior to those of materials sintered under vacuum.

Estimation of the temperature of the ductile-brittle transition of aluminum matrix composite materials at negative temperatures using classification of acoustic emission signal pulses

The results of experiments on assessing the mechanical properties, in particular the temperature of the ductilebrittle transition of aluminum matrix composite materials at negative temperatures using the classification of acoustic emission signal pulses, are presented. It is established that this transition is absent at temperatures down to –100 °C and, therefore, it is possible to use aluminum matrix composite materials for the manufacture of suspension elements for equipment operating in Arctic and Antarctic conditions. Keywords aluminum matrix composite materials, mechanical properties, temperature, ductile-brittle transition

Investigations on microstructure, hardness and tribological behaviour of AA7075-Al2O3 composites synthesized via stir casting route

Aluminium matrix composite (AMC) materials play an important role in the field of automobile and aerospace industries due to their excellent properties. In this research, aluminium alloy (AA7075) was reinforced with alumina (Al2O3) particles to improve their hardness and tribological behaviour of the base alloy. Four composites were prepared by varying the content (4, 8 and 12 wt.%) of Al2O3 particles through the stir casting technique. The surface morphology of the proposed composites ensured the uniform distribution of Al2O3 particles into the matrix alloy. The hardness of the composite was measured using a Brinell hardness tester and the maximum value of hardness was found in the AA7075 - 8 wt.% Al2O3 composite. Hence, a tribological investigation was carried out on this AA7075 - 8 wt.% Al2O3 composite. Load (P), sliding speed (V) and sliding velocity (D) were taken as the wear parameters for conducting the experiments. A Technique for Order Preference by Similarity to Ideal Preferred Solution (TOPSIS) approach has been applied to find out the optimal conditions of parameters to obtain the lowest wear rate (WR) and the co-efficient of friction (COF). The results showed that the lowest WR and COF was obtained at ‘P’ of 15 N, ‘V’ of 1 m•s-1 and ‘D’ of 1000 m•s-1. ANOVA results revealed that ‘P’ is the factor with the most significant contribution (38.36%), followed by ‘D’ (28.32%). The worn surface morphology of the confirmation experiment specimen was investigated by SEM and the wear mechanism was reported.

Deformation of Al–Zn–Mg–Cu composite samples under nonstationary thermomechanical conditions

The paper studies the technology of deformation and heat treatment of an aluminum-matrix composite material under nonstationary conditions, which is upsetting with gradual heating to near-solidus temperatures under mild loading conditions. The composite material is based on the V95 aluminum alloy discretely reinforced with 10% of SiC particles. The purpose of the study is to compare the deformation behavior of the samples and analyze their microstructure under different conditions of thermal deformation processing. The structure of the material is studied by optical and electron scanning microscopies. The paper discloses the behavior of the rate of relative strain as dependent on temperature, as well as the features of structure formation in an aluminum-matrix composite depending on the heating conditions. The most pronounced differences are found in the central part of the samples closer to the deforming tool (flat dies). On the symmetry axis in the central region of the samples there are differences in the crystallographic orientations of the material textures. Microhardness values and their distribution on the section are obtained. For the sample with slow heating, there is no tendency for the increase of the microhardness values in the regions with high values of plastic strain, this being indicative of a more complete recrystallization process and lower dislocation density.

Influence of particulates on microstructure, Mechanical and Fractured behaviour on Al-7075 alloy composite by FEA

ABSTRACT Aluminium alloys are employed in advanced applications due to their desirable combination of low density, high strength, durability, availability, and cost vs. competing materials. The characteristics described above can be increased further by employing aluminium matrix composite materials reinforced with harder particles. The hybrid aluminium alloy (Al7075) composite was made in an electric resistance furnace using the sand mould process and reinforced with alumina (Al2O3) and boron carbide (B4C) particles. The purpose of this research to investigate the mechanical characteristics of Al7075-Al2O3-B4C hybrid composites with stable Al2O3 weight percentages (4%) and varied B4C weight percentages (2–6%). Mechanical characteristics includes tensile and compressive strength, hardness, and microstructure analysis were evaluated on the pure and cast specimens. In this study, which followed the ASTM standard, the mechanical characteristics of Al7075 alloy hybrid composites were examined experimentally and validated using FEA. The results showed that when hard ceramic particles (Al2O3/B4C) were added to matrix alloy (Al7075), mechanical characteristics such as compressive strength and hardness improved while tensile strength was reduced. The static structural tensile test was successfully simulated in ANSYS. It was observed that both FEA results and analytical results were correlated.

Aluminium Matrix Composite Materials Reinforced by 3D-Printed Ceramic Preforms.

This article employed the fused deposition modelling (FDM) method and gas-pressure infiltration to manufacture alumina/AlSi12 composites. Porous ceramic skeletons were prepared by FDM 3D printing of two different alumina powder-filed filaments. The organic component was removed using a combination of solvent and heat debinding, and the materials were then sintered at 1500 °C to complete the process. Thermogravimetric tests and DTA analysis were performed to develop an appropriate degradation and sintering program. Manufactured skeletons were subjected to microstructure analysis, porosity analysis, and bending test. The sintering process produced porous alumina ceramic samples with no residual carbon content. Open porosity could occur due to the binder's degradation. Liquid metal was infiltrated into the ceramic, efficiently filling any open pores and forming a three-dimensional network of the aluminium phase. The microstructure and characteristics of the fabricated materials were investigated using high-resolution scanning electron microscopy, computer tomography, hardness testing, and bending strength testing. The developed composite materials are characterized by the required structure-low porosity and homogenous distribution of the reinforcing phase, better mechanical properties than their matrix and more than twice as high hardness. Hence, the developed innovative technology of their manufacturing can be used in practice.

Structure and tensile fracture mechanism of aluminum matrix composites produced by internal oxidation

This article presents experimental results of resistance against fracture upon static tension of cast aluminum matrix composites based on aluminum with various content of Al2O3 strengthening phase. The cast aluminum matrix composite materials were produced by the technology based on burnout of aluminum melt upon interaction with oxygen. Two batches of ingots with various content of solid phase were smelted for tests of static strength. The average particle size of strengthening phase of predominantly prismatic morphology was 60–80 μm, and their content varied from 15 to 25 %. The fracture surfaces obtained upon static uniaxial tension of the considered samples were studied on the samples destroyed at maximum stress. The fracture surfaces were analyzed using an optical microscope with expanded options due to improved long-focus system and digital processing of images based on unique procedure of 3D structure analysis. For indepth analysis of characteristic fracture region a scanning electron microscope was used equipped with energy and wavelength dispersive elemental analyzers. It was established in the studies that in the samples with lower content of dispersed phase, the fracture is characterized by mixed heterogeneous in terms of macrogeometry pattern. This can be interpreted as dry fibrous fracture with visible crystalline pimples and breakaways. With an increase in the solid phase, a mixed, sufficiently homogenous in terms of macrogeometry, fracture pattern of fanlike fibrous structure can be observed. Crystalline pimples were also detected of a different fracture surface area, as well as breakaways of other geometrical sizes. The features of changes in the relief of fracture surface and the fracture mechanisms of the obtained composites have been detected and described.

Investigation of thermophysical processes of obtaining various aluminum matrix composites

The possibilities of obtaining aluminum matrix composite materials of the composition Al-Al2O3 are considered by the method of liquid-phase oxidation of aluminum by purging the melt with oxygen. The obtained materials are a two-phase system with different concentrations of the solid phase. An algorithm for calculating the kinetics of aluminum oxidation in obtaining the oxide phase of an aluminum matrix composite is proposed. It is established that the beginning and completeness of the reaction on the surface of the gas bubble determines the synthesis of the oxide phase and is determined by the functions T(t), h(t) in the region of dynamic time delay, which, in turn, the queue is revealed as a function of the temperature in the contact zone of the gas bubble with the melt, taking into account the duration of the heating of the bubble along the cross section and the radius of the bubble itself. The microstructures of the obtained materials with different structural-phase state with variations in the time of purging and oxygen supply to the aluminum melt are presented. Keywords: aluminum matrix composite material, high temperature oxidation, gas bubble.

Влияние армирования TiC и TiB2 на свойства и структуру алюминиевого сплава АМг2

The paper presents the results of a study devoted to studying the effect of the type of reinforcing phase on the structure and properties of an aluminum matrix composite material (AMCM) obtained by the method of self-propagating high-temperature synthesis (SHS) in a melt. In the course of the research, an analysis was carried out and a choice was made to use titanium carbide and titanium diboride as reinforcing phases. During the experimental synthesis of SHS in the melt, composite materials AMg2 – 10 % TiC and AMg2 – 10 % TiB2 were obtained. In the course of further studies, microstructural, micro-X-ray spectral and X-ray phase analyzes were carried out, according to the results of which it was revealed that the technology used leads to the formation of the target TiC phase in the AMg2 – 10 % TiC composite and TiB2, Al3Ti phases in the AMg2 – 10 % TiB2 composite. On the synthesized samples of composite materials, an assessment was made of physical and mechanical characteristics: hardness, porosity and electrical conductivity. It was found that the hardness of AMCM obtained by the SHS method based on the industrial alloy AMg2 reinforced with titanium carbide is higher than the hardness of AMCM reinforced with titanium diboride by 44 MPa. Also, the porosity of the AMg2 – 10 % TiC composite is lower than that of the AMg2 – 10 % TiB2 composite by 6 %. This paper also shows the effect of heat treatment on the physical and mechanical properties of AMg2 – 10 % TiC and AMg2 – 10 % TiB2 composite materials. Carrying out additional heating leads to an increase in the hardness values of composite materials, as well as to a decrease in porosity. According to the results of a complex of studies, the use of titanium carbide is recommended as a reinforcing phase.

Control of Al4C3 phase formation in aluminum matrix composites reinforced with carbon nanostructures

This brief overview provides a systematic organization of the known thermodynamic data to justify approaches for inhibiting the in-situ formation of Al4C3 reaction between carbon nanotubes and aluminum matrix in composite materials. Based on the literature data, the Gibbs free energy value at a temperature of 600 ºC is calculated for aluminum and carbon interactions with various substances. Approaches for inhibiting the interfacial reaction and the formation of the Al4C3 phase in aluminum matrix composites are proposed by controlling their composition. These approaches involve alloying the matrix with different elements and ex-situ modification of carbon nanotubes through the creation of coatings with varying compositions on their surface prior to their incorporation into the matrix. Literature data on the effect of the interfacial layer on the properties of Al/CNT composites are presented. The promising outlook of the interface design strategy by controlling the type and thickness of the interphase layer for the engineering of composites with improved properties is shown. This approach can be useful in the development of aluminum matrix composite materials with balanced properties for a wide range of applications.

Исследование теплофизических процессов получения различных алюмоматричных композитов

The possibilities of obtaining aluminum matrix composite materials of the composition Al−Al2O3 are considered by the method of liquid-phase oxidation of aluminum by purging the melt with oxygen. The obtained materials are a two-phase system with different concentrations of the solid phase. An algorithm for calculating the kinetics of aluminum oxidation in obtaining the oxide phase of an aluminum matrix composite is proposed. It is established that the beginning and completeness of the reaction on the surface of the gas bubble determines the synthesis of the oxide phase and is determined by the functions T(t), h(t) in the region of dynamic time delay, which, in turn, the queue is revealed as a function of the temperature in the contact zone of the gas bubble with the melt, taking into account the duration of the heating of the bubble along the cross section and the radius of the bubble itself. The microstructures of the obtained materials with different structural-phase state with variations in the time of purging and oxygen supply to the aluminum melt are presented

Development of an aluminium matrix composite material with the addition of dispersed particles of graphite, operating under conditions of increased friction

The paper proposes a method for obtaining a composite material based on aluminum with the introduction of dispersed particles of graphite powder at the stage of obtaining samples. On the obtained experimental samples, which are cylinders with a diameter of 20 mm. and a height of 10 mm, and the properties of this material, namely hardness and wear resistance.

Применение углеродных нановолокон в аддитивном производстве алюмоматричных композитов

The possibility of using carbon nanofibers (CNF) in the production of aluminum matrix composite materials (AMC) by selective laser melting (SLM) has been experimentally shown. The powder composition based on the AlSi10Mg alloy with the addition of 0.5% (wt.) CNF was prepared by mechanical activation. The optimal parameters of the SLM process were determined to ensure the density of the synthesized AMC samples over 99%. The retention of CNFs in the AMC structure and the formation of Al4C3 inclusions, which have a higher strength and hardness as compared with the initial aluminum alloy AlSi10Mg, lead to strengthening of the synthesized material, the microhardness of which is 149 ± 8 HV, that is 20% higher than the hardness of the AlSi10Mg alloy.

Одностадийный синтез смеси наночастиц WC-=SUB=-1-x-=/SUB=- и гибридного наноматериала на основе многостенных углеродных нанотрубок с нанопокрытиями WC-=SUB=-1-x-=/SUB=-

By the method of chemical vapor deposition of tungsten hexacarbonyl at atmospheric pressure in an argon flow has been used to obtain promising fillers for aluminum matrix composite materials in the form of a mixture of nanoparticles of non-stoichiometric cubic tungsten carbide (WC1-x) and hybrid nanomaterials based on multi-walled carbon nanotubes decorated with nonstoichiometric cubic tungsten carbide. The influence of chemical vapor deposition (CVD) parameters on the morphology of samples was studied and the optimal synthesis conditions were selected. The structure and composition of the synthesized materials were studied by electron microscopy and X-ray phase analysis

Features of cutting processing of disperse-filled of aluminum-matrix composite materials

The results of studies of machinability by cutting of experimental samples of promising aluminum-matrix disperse-filled composition materials are presented. The axial force and cutting torque during drilling were measured, the surface roughness of the obtained holes was studied, and the shape of the chips was analyzed. Analysis of the obtained data allowed to determine the composition of aluminum-matrix material, which provides lower cutting forces, roughness of the machined surface and better chip formation. The influence of the filler composition on the machinability by cutting of aluminum-matrix composites is shown.

Thermodynamics of the effect of alloying on phase formation during crystallization of aluminum matrix composites with exogenous reinforcement

A thermodynamic assessment of the effect of alloying elements (Si, Mg, Cu, Ti) on phase formation processes during the production and liquid-phase processing of cast aluminum matrix composite materials with exogenous reinforcement (Al–SiC, Al–B4C) was carried out. It was shown that without suppressing Al–Si–C and Al4C3 carbide formation in the range of carbon concentrations from 0 to 4.5 wt.%, the equilibrium phase composition of Al–SiC composites in the solid state at 423 to 575 °C lies in the (Al) + Si + Al4SiC4 three-phase region, and the Al4SiC4 ternary carbide is replaced by the Al8SiC7 compound at a temperature below 423 °C. SiC and B4C phases in Al–SiC–Cu and Al–B4C–Cu systems are stable in the entire crystallization range and do not interact with aluminum or copper. In the Al–SiC–Mg system, the crystallization of composites containing more than 0.58 wt.% magnesium ends in the (Al) + Al3Mg2 + SiC + Mg2Si four-phase region. In the Al–SiC–Ti system, the end of crystallization is observed in the (Al) + Al3Ti + SiC three-phase region. In the Al–B4C system, once Al4C3 phase formation is suppressed, aluminum borides are formed with a deviation from the concentrations of elements providing 10 vol.% B4C towards boron increase and free carbon is formed with a deviation towards boron decrease. Under equilibrium conditions, Al–B4C–Si system crystallization ends in the (Al) + B4C + AlB12 + Al8SiC7 four-phase region (at a silicon content of up to 0.67 wt.%, and in the (Al) + Si + AlB12 + Al8SiC7 region at a higher silicon content. In the Al–B4C–Ti system, crystallization ends in the (Al) + TiB2 + B4C three-phase region at a titanium content of less than 0.42 wt.%.

Obtaining of aluminum-matrix composite materials, dispersedreinforced with ceramic particles

Повышенная устойчивость к нагреву является одним из важных требований при создании перспективных материалов и изделий из них. Такому требованию потенциально удовлетворяют функциональные металломатричные композиционные материалы, армированные частицами керамики и обладающие высокими физико-механическими свойствами. По причине доступности и высокой технологичности существенную часть металломатричных материалов составляют композиционные материалы на основе алюминия и его сплавов. В настоящей статье предлагается новый способ получения дисперсно-армированных алюмоматричных композиционных материалов, основанный на совмещении метода порошковой металлургии и метода in situ. Технический результат предлагаемого способа ― исключение затрат на специальное оборудование и оснастку для создания как механического давления на заготовку в процессе нагрева, так и вакуума или среды инертного газа.

An Insight into Mechanical and Metallurgical Behavior of Hybrid Reinforced Aluminum Metal Matrix Composite

Hybrid reinforced particulate aluminum matrix composite materials (HAMCs) are a breakthrough kind of material made by combining two or more distinct reinforcing components in the aluminum (Al) matrix. Composites with many reinforcing phases offer a superior overall mix of characteristics than composites with only one. This article’s wide literature review of metal matrix composite (MMC) especially for aluminum matrix composites (AMC) was carried out. Discussions of various widely adopted synthesis methods such as stir casting and powder metallurgy have been presented. The effect of various reinforcement ceramic particles such as silicon carbide (SiC), aluminum oxide (Al2O3), graphite (Gr) on the mechanical and metallurgical properties of MMC has been reviewed. The summary of various characterizations such as X-ray diffraction (X-RD), and optical microscopy (OM) including testing such as hardness, tensile, compressive, and tribological behavior has been discussed in detail to demonstrate a full grasp of the many features of HAMCs, such as manufacturing, physicomechanical properties, wear, and corrosion characteristics. Future developments and potentially useful materials as alternative reinforcements are discussed at the end of the review.

Study of the TIG weldability of aluminum matrix composite material AMg2-TiC

Subject of research: Weldability of the composite alloy AMg2-TiC.
 Purpose of research: Matrix alloy AMg2 is often used in welded joints. Reinforcement with a highly dispersed ceramic phase of titanium carbide leads to an increase in the hardness and strength of the alloy; therefore, it is necessary to study how the composite material behaves during and after welding.
 Methods and objects of research: The object of study is the AMg2-TiC composite alloy obtained by the method of self-propagating high-temperature synthesis. Microstructural analysis was carried out on a Jeol JSM 6390A scanning electron microscope. The elemental composition was determined by X-ray microanalysis on a Jeol JSM 6390A scanning electron microscope with a Jeol JED-2200 attachment. The hardness of the samples was determined on a hardness tester ZIP TK=2M using the Brinell method according to GOST 9012-59. Weldability tests were carried out by argon-arc welding using an Everlast Power TIG 210 EXT welding inventory and filler materials that most closely match the chemical composition of the matrix alloy.
 Main results of research: This paper shows the possibility of welding a composite material using the TiG method. The weldability of the composite was rated as satisfactory. Highly dispersed particles of the reinforcing phase do not dislocate from the area of ​​the base metal to the area of ​​the weld. The hardness of the composite material after argon-arc welding does not fall, but remains at the same level. The porosity in the weld zone of the composite is less than in the weld zone of the matrix alloy.