Metal Matrix Composites

This article deals with a summary of different fabrication methods of Aluminium Metal Matrix Composite (AMMC). This modern age demands the lightweight materials with very high strength, wear resistance, and corrosion resistance property for various industries i.e. aerospace, automobile, sports, etc. These requirements can't be fulfilled by the monolithic alloy or conventional materials. Metal Matrix Composite (MMC) overcomes these limitations of the monolithic alloys because MMCs have desired properties like high strength to weight ratio, good mechanical as well as good tribological properties and due to its advantageous properties MMCs are used for automobile & aircraft. The use of MMCs reduces the power requirement and also gives low emission and low noise. This article focused on the various techniques developed for the fabrication of AMMCs by the no. of researchers in the last few decades. These methods are either liquid state processing or solid-state processing. In the case of weight-saving requirements, researchers used AMMCs due to its lightweight property.

In this present research particulate reinforced aluminium metal matrix composite is developed by using sand mould and liquid stir casting processing route in which AA5052 reinforced with 5 wt. % SiC particulates of 63µm particle size. The density, porosity, micro-hardness, and compressive strength of SiC particulate reinforced AA5052 MMC were investigated and compared these properties with similar properties of unreinforced AA5052. The microstructure of the developed composite was also analysed by using optical microscopy, SEM, and XRD. Developed particulate reinforced Al metal matrix composite gives improved hardness and compressive strength as compared to the unreinforced AA5052. The addition of 5 wt. % SiC particulates increases the density of AA5052.

The weight saving requirement for automobiles has become more important, since the increase in the environmental issues. For boosting the fuel economy, maintaining safety and performance of modern automobiles; lightweight composite materials are essential. For acceleration of a lighter object, less energy is required as compare to acceleration of heavier one; so the lightweight composite materials offer the great potential for increasing vehicles efficiency. Decrease in fuel consumption gain by reduction in vehicle weight. By replacing steel & cast iron conventional components with lightweight composite materials such as Mg & Al metal matrix composite, carbon & glass fiber reinforced polymer composites can directly reduce the weight of the parts of an automotive i.e. engine block and chassis and results in reduction of fuel consumption by the vehicle. By the use of light composites in automotive can also carry additional advanced emission control system, safety devices, and integrated electronic system without increase in the overall weight of vehicles. It can reduce the exhaust emission and enhanced the fuel economy.

The positive impact of nanoparticles on the behaviour of composite microstructures has been studied. These studies include the material characteristic features, the production methods, suitability with the other phases, surface area, the scattering process, rigidity, and other topics. The assessment of the selection of nanomaterials for a particular tender and their impact on the bulk material connected to loading has remained neglected. This is unfortunate because the review was necessary. As a result, the effects of nanoparticles were investigated in this work, constructed on definite filler categories. It also demonstrated the optimal filler quantity for the improvement of mechanical parameters (such as strength and stiffness) and fracture toughness from both an interlaminar and an intralaminar point of view. In addition, the impacts of soft fillers, hard fillers, and hybrid additives were analysed and grouped to demonstrate how certain fillers might have amazing effects on the enhancement of particular properties. In addition, the most effective application of nanomaterials in relation to loading conditions was articulated in order to provide structural engineering engineers and scientists with a prompt suggestion. This research provides some insight into how nano-filler and nano-particles affect the beginning of damage in fiber-reinforced plastic composites as well as their behaviour.

In the present study, the nickel aluminide NiAl-based composite, reinforced with yttrium oxide Y2O3 with addition of titanium, was prepared by sintering at 1350 ° C for one and a half hours under an atmosphere of argon gas. Experimental investigation on electrical discharge machining of NiAl composite is performed with a view to correlate the process parameters with the responses for indicating the effect of the alloying addition on the machining performance of NiAl. Electro-discharge machining was used to study the machinability of the prepared composite. The machinability of NiAl was investigated based on the material removal rate, electrode wear rate, white layer thickness, and the surface roughness of the machined samples. The machining tests were performed under a wide range of machining parameters involving the pulse current (Ip) (8, 12, and 20) Amp. , pulse on time (TON) (45, 60, and 80) µsec, and pulse off time (TOFF) (20, 35, and 50) µsec, keeping the other parameters at fixed values. Electro-discharge machining process has been successfully modeled using response surface methodology (RSM) and central composite design (CCD) within "Minitab 17" and model adequacy checking is also carried out. The second-order response models have been validated. Analysis of variance (ANOVA) at constant significance levels of 0.05 was used to predict the most affecting parameters on the machining outputs. Optimization plots indicated that the maximum material removal rate (9.9312 µm) can obtained at (TON = 80 µs, TOFF = 20 µm, and Ip = 17.8182 Amp.), minimum electrode wear rate (0.2552 µm) can achieved at (TON = 45 µs, TOFF = 50 µm, and Ip = 8 Amp.), minimum surface roughness can gained at (TON = 45 µs, TOFF = 50 µm, and Ip = 8 Amp.), and minimum white layer thickness (4.9335 µm) can gotten using machining conditions of (TON = 45 µs, TOFF = 50 µm, and Ip = 8 Amp.

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Your article is protected by copyright and all rights are held exclusively by ASM International. This e-offprint is for personal use only and shall not be self-archived in electronic repositories. If you wish to selfarchive your work, please use the accepted author's version for posting to your own website or your institution's repository. You may further deposit the accepted author's version on a funder's repository at a funder's request, provided it is not made publicly available until 12 months after publication.

Grinding of metal matrix composites is a challengin g task on account of the hybrid nature of their constituents. In this study, the influence of grind ing process and parameters on surface finish and su rface integrity of MMC workpiece was investigated. A high performance resin bonded diamond grinding wheel was used owing to the abrasive nature of SiC reinfo rcements. As–ground workpiece was characterized by light microscopy, scanning electron microscopy, pro filometry and by variations in near surface microhardness values. The emphasis has also been gi v to the influence of grinding parameters on surface residual stresses. A model of the reinforce ment particles–grinding wheel interaction has been proposed. The experimental material was a powder me tallurgically produced AA–2124 based metal matrix composite reinforced with 25 volume percent of fine (2-3 μm) SiC particles in T6 heattreatment condition.

When choosing a material for automobile piston components, be sure to choose one that satisfies all necessary specifications, like durability, resistance to temperature, and wear resistance. To achieve maximum efficiency and effectiveness, factors including cost, weight, and production procedures are also taken into account. Aluminium alloys that are forged iron, and steel are common material for piston components; each has certain benefits and compromises in terms of expense and efficiency. Introduction: Material selection for auto piston components is critical to ensuring top performance and long-term durability. The piston, as a vital engine component subjected to high temperatures, hardship, and wear and tear, necessitates a material that promotes efficient combustion, lowers friction, and maintains its structural integrity. When selecting materials for automobile pistons such as aluminium alloys, wrought iron, or steel, aspects such as heat conductivity, resistance to wear, size, expense, and manufacturing capability are carefully considered to satisfy the specific needs of the application. Research Significance: Aluminum, steel, along with iron are the better frequently used goods for pistons. The effort from the expanding gas at great heat matters about the inside. Cylinder and many other important factors determine proper piston selection Material necessity are balanced more demanding, just as no single material meets all the properties required for a distinct application. Method: The weighted sum method is a decision-making approach that involves assigning weights to different criteria or objectives and combining them to make an overall assessment. It allows decision-makers to prioritize and balance various factors based on their relative importance. By utilizing this method, complex decision problems can be simplified and converted into a single weighted score, facilitating a clearer understanding of trade-offs and aiding in the decision-making process.

Abstract—Forging, milling, turning, grinding and shaping etc. are the various industrial manufacturing processes which generate the metal waste. Grinding is extensively used in the finishing operation. The waste generated contains significant impurities apart from the metal particles. Due to these significant impurities, it becomes difficult to process and gets usually dumped in the landfills which create environmental problems. Therefore, it becomes essential to reuse metal waste to create value added products. Powder injection molding process is used for producing the porous metal matrix framework. This paper discusses the presented design of the porous framework to be used for the liquid filter application. Different parameters are optimized to obtain the better strength framework with variable porosity. Carbon nanotubes are used as reinforcing materials to enhance the strength of the metal matrix framework.

The wear behaviour comparison of Al/SiC and Al/Al2O3 composites prepared by stir casting technique is investigated to find out the effects of weight percentage of SiC/Al2O3, load and the number of strokes on a reciprocating wear testing machine. The MMC pins are prepared with different weight percentage of SiC and Al2O3 (10, 15 and 20 %). The tests are carried out with different load conditions (25, 50 and 75 N) and different number of strokes (420,780 and 1605 strokes). Wear surfaces of tested samples are examined in Scanning Electron Microscope (SEM). Hardness test and impact test are also carried out on the MMC samples. The experimental results shows that hardness of composites increases with increase in SiC and Al2O3 particle and the impact strength decreases with increase in SiC and Al2O3 content. The volume loss of MMC specimens are less than that of the matrix alloy. The temperature rise near the contact surface of the MMC specimens increases with increase in wt% of SiC and A...

The synthesis of magnesium silicon nitride (MgSiN 2 ) by direct nitridation of a Si/Mg 2 Si/Mg/Si 3 N 4 powder mixture is described. A nucleation period at 550°C and stepwise heattreatment schedule up to 1350°C was adopted for the synthesis of MgSiN 2 powder, based on TG-DTA measurements. The influence of the ratio of constituents on the final phase composition also has been studied. The content of magnesium and silicon in the starting powder should fulfill the conditions Mg 2 Si/Mg > 3 and Si 3 N 4 /Si tot > 0.5 to obtain single-phase MgSiN 2 . The silicon particle size of <0.5 m is preferable to decrease the time of nitridation. The oxygen content of assynthesized powders is in the range 0.9 -1.2 wt%. However, the oxygen content of MgSiN 2 powder decreases further by the addition of 2 wt% CaF 2 or 0.75 wt% carbon and reaching the lowest value of 0.45 wt% oxygen after carbothermal reduction in an alumina-tube furnace.

effect of Nb and C additions on the phase composition, microstructure, and creep resistance of Fe 3 Al-type alloys is investigated. Two alloys, which contained (at. pct) (i) 27.6 Al, 1.15 Nb and 0.19 C (Fe balance) and (ii) 27.1 Al, 1.11 Nb, and 0.76 C (Fe balance), were studied in a temperature range from 873 K to 1073 K (600 °C to 800 °C). The carbide in both alloys was identified as Nb 6 C 5 . The creep data can be rationalized by introducing a threshold stress, below which, the creep rate is negligible. The threshold stress and an effective stress exponent were found simultaneously by a numerical method. Using the obtained values of the threshold stress, the activation energy of creep was determined to be 328 kJ/mol. The effective stress exponent varied from 2.0 to 3.1. A breakdown of power-law behavior was observed at higher stresses. The transition occurred at the normalized creep rate of _ e=D ¼ 10 13 m À2 , which agrees with the rule suggested by Sherby and Burke and the diffusion coefficient D corresponding to the diffusion of Al in Fe-Al.

FeAl-based MIL composites of various iron alloys were fabricated with an innovative "multiple-thin-foil" configuration and "two-stage reaction" strategy. Alternating stacked metal foils were reactive sintered via SPS at 600 o C and 1000 o C to grow intermetallics. The "multiple-thin-foil" configuration reduces reaction time, enables local chemical composition control and allows metal/intermetallic combinations, which cannot be produced via the conventional methods. Fe-FeAl, 430SS-FeAl, and 304SS-FeAl MIL composites can be synthesized with desired metallic/intermetallic ratios, where FeAl is the single intermetallic phase present in the composites. Microstructure analysis via SEM, EDS, and EBSD confirms phase identification and reveals the formation of transition layers. The transition layer, which incorporates the composition gradient between the metal (Fe, 430SS or 304SS) and the FeAl intermetallic phase, provides a gradual change in mechanical properties from the metal to intermetallic layers, and further functions as a chemical barrier into which other undesired intermetallics dissolve. Driven by diffusioncontrolled growth, grains in the transition layers and FeAl regions exhibit ordered arrangement and sintering textures. Hardness profiles from the metal layer to FeAl region reveal the correlation between local mechanical properties and local chemical compositions. In compression testing, the compressive strength can reach 2.3 GPa with considerable plasticity, establishing the best mechanical properties of any MIL composites synthesized to date.

The risk of cracking/debonding of a cement overlay used to repair or strengthen an existing structure is still a key issue. Current bond test methods are not designed to measure the combined effect of peeling (mode I) and shear (mode II) on the interface. A few existing models propose theoretical approaches to predict that, but they were fitted on specific cases and lack in generality. In addition, controversial opinions about the influence of both the moisture level of the substrate surface prior to the application of the overlay and properties of the latter on the loading bond capacity call for further investigations. In this work, a cohesive model is developed to predict the loading bond capacity of an existing concrete structure overlaid by a layer of HPFRC/UHPFRC. Different bond tests were specifically designed for calibrating the cohesive parameters employed into the model, which also takes into account the type of the overlay used and the moisture conditioning level. An experimental campaign confirmed the reliability of the predictions of the proposed theoretical model.

In this research, the mechanical properties (microhardness and wear) of Al-8Si-3Cu-2Zn nanocomposites with 0, 2, and 5% by weight of tungsten disulfide nanoplates have been investigated. The studied nanocomposite was produced through mechanical grinding and hot pressing at a temperature of 510 degrees Celsius. The microstructures of powders before and after mechanical grinding and sintered samples were studied through electron microscopy (SEM). By examining the worn surfaces after the wear test by electron microscope, the cause of weight loss was investigated. The results show that by adding tungsten disulfide nanoplates up to 5% by weight, the microhardness of the samples increases more than twice and from 50 Vickers for Al-8Si-3Cu-2Zn to 101 Vickers for Al-8Si.-3Cu-2Zn nanocomposite reaches -5%WS2. According to the results of the wear tests, the wear rate for Al-8Si-3Cu-2Zn-5%WS2 will decrease by 32% %, compared to the Al-8Si-3Cu-2Zn alloy background. Therefore, Al-8Si-3Cu-2Zn-5%WS2 nanocomposite can be used as a self-lubricating nanocomposite with favorable wear properties.

In electrical discharge machining (EDM), a complete and clear theory has not yet been established. The developed theory (physical models) yields results far from reality due to the complexity of the physics. It is difficult to select proper parameter settings in order to achieve better EDM performance. However, modelling can solve this critical problem concerning the parameter settings. Therefore, the purpose of the present work is to develop mathematical model to predict performance characteristics of EDM on Ti-5Al-2.5Sn titanium alloy. Response surface method (RSM) and artificial neural network (ANN) are employed to develop the mathematical models. The developed models are verified through analysis of variance (ANOVA). The ANN models are trained, tested, and validated utilizing a set of data. It is found that the developed ANN and mathematical model can predict performance of EDM effectively. Thus, the model has found a precise tool that turns EDM process cost-effective and more efficient.

The use of agricultural residue has been considered an economic and environmentally friendly approach for development of aluminium composites. In this study, Al powder (Al) was reinforced with coconut shell ash (CSA), rice husk ash (RHA), and cassava peel ash (CPA) for enhanced physicomechanical performance of the resulting composites. Five samples (A o -Al, A 1 -Al + 15RHA, A 2 -Al + 5CSA + 5RHA + 5CPA, A 3 -Al + 15CPA, and A 4 -Al + 15RHA) were prepared in a two-step stir-casting technique and characterized based on physical, mechanical and metallurgical properties. Microstructural analysis revealed that all the particles bonded well with the aluminum alloy. The densities of samples A 1 , A 2 , A 3, and A 4 reduced by 4.78%, 7.75%, 11.44%, and 14.76%, respectively compared to the control sample A o while porosities rose by 2.1%, 2.23%, 2.56%, and 2.98% respectively. Sample A 2 has the highest tensile strength (39.84 MPa) and hardness (120 HBR) which denote 33.60% and 64.27% enhancement compared to the unreinforced sample. These observations can be attributed to the presence of intermetallic compounds such as Fe 3 Si and Al 6 Fe present in the composites as well as uniformly distributed and strongly bounded reinforcement within the aluminum matrix. The composite made from the combination of the three reinforcements gave the best physicomechanical properties and therefore recommended for engineering applications.

Light magnesium nanocomposites, offering great weight savings, have a great potential to be utilized in aerospace and automotive industries. They have also been attracted much attention to be evaluated as biomaterial recently owing to their in vitro biodegradability and biocompatibility properties. In the present research, the Mg3Zn/TiB2-CNT nanocomposites were successfully manufactured using mechanical alloying, cold compaction at 600 MPa and finally sintering at 560 °C for 1 h. Their microstructural, mechanical, wear and corrosion properties were investigated extensively for comparison with the Mg3Zn alloy. It was found that the microhardness of the Mg3Zn nanocomposites increased directly with the hybrid reinforcement ratio. In parallel to the hardness, an addition of 15 vol % TiB2-CNT reinforcement to the Mg3Zn alloy allowed to the improvement of the compressive strength by of 46.3 % at a reasonable ductility level of ∼7.8 % compared to the Mg3Zn alloy. The crystallite size, decreasing with an augmentation in the reinforcement content steadily, was obtained to be smaller than 100 nm for the bulk Mg3Zn nanocomposites. Moreover, the wear loss of Mg3Zn alloy reduced by ∼45 % upon the incorporation of 15 % hybrid reinforcement due to the occurrence of a stable tribolayer between the working couple. An additional benefit of the incorporation of hybrid reinforcement into Mg3Zn alloy was also obtained in the progress of corrosion resistance significantly. The corrosion rate was recorded to be 1462.6 mpy for Mg3Zn but it decreased to 276 mpy upon the incorporation of 10 % hybrid reinforcement into the alloy.

The present investigation is aimed at studying the effect of dispersoid content and effect of chill on microstructure and mechanical properties of aluminum alloy (LM 13) hybrid metal matrix composites reinforced with garnet and fixed 3wt.% carbon. The size of the garnet particles varies from 50 to 80 μm and amount of addition varies from 3 to 12 wt.% in steps of 3 wt%. By using chills of different material with different volumetric heat capacity (VHC), the effect on the microstructure evolution was examined. Stir casting process was used to produce chill cast aluminum alloy-garnetcarbon particulate composites in moulds containing various chills of copper, steel, iron and silicon carbide to accelerate the solidification. The fabricated composites were tested for their hardness and ultimate tensile strength properties according to ASTM standards. The effect of chill and reinforcement characteristics was presented and compared with the hybrid composite without chill material. Microstru...

The development of lightweight and high-performance materials has become a pivotal focus in automotive engineering due to the growing demand for energy-efficient and environmentally friendly vehicles. This research focuses on the use of Aluminium Metal Matrix Composites (Al-MMCs) as substitute materials for steel in the design and improvement of leaf springs, which are vital in vehicle suspension systems. By employing CAD modelling and FEA, the mechanical behaviour of the developed Al/SiC MMC and Al/B4C MMC leaf springs are analysed and compared under different static load conditions of 12,500 N & 17,500 N. The analysis focuses on deformation, stress distribution, and weight reduction compared to conventional steel leaf springs. These outcomes indicate that Al-MMCs can achieve up to 60% weight reduction with an improvement or comparable stresshandling capacity. Among all the materials, the stiffness and lower deformation at the maximum load indicate that Al/B4C MMC is a potential material for high-performance and lightweight vehicles. This study focuses on the potential of enhancing Al-MMCs for better fuel economy and vehicle performance by using sustainable automotive material choices. The results of this research will provide possibilities for other high-risk automotive applications of composite material by explaining the behaviour and performance of the material and new designs.

In this research, mechanical and microstructure properties of cold pressing (CP) and extrusion (EXTR) specimens produced via powder metallurgy were investigated and compared. For this comparison, EXTR specimens were hot extruded at 565°C with an extrusion ratio of 4:1. Likewise, CP specimens were compacted under a pressure of 600 MPa and sintered at 565°C. Then, the effects of volume fraction on SiC and B 4 C particle reinforced Alumix-231 composites were investigated using optical microscopy, SEM and macro hardness testing. Compared to CP specimens, it was found that the hardness and mechanical strengths of Alumix-231 specimens without reinforcement produced using EXTR increased in the ratio of 140 and 190%, respectively. The test results showed that increase in uniformity of reinforcement dispersion and enhancement of interfacial bonding strength of the composites is the main reasons for the improvement of EXTR specimens. As a result, EXTR improves mechanical properties of the specimens by decreasing the porosity and thus increasing the density and interfacial bonding strength.

The rapid evolution of the mechanical industry necessitates reliable and innovative materials. Metal matrix composites (MMCs) have emerged as a leading contender for performing vital roles in this field. Carbon nanostructures, such as graphene and carbon nanotubes (CNTs), are particularly well-suited as reinforcement materials in MMCs. It has been found by recent experimental studies that incorporating CNTs and graphene as reinforcements into metal matrix composites, such as aluminum, magnesium, titanium, nickel, and copper matrices, can significantly enhance the mechanical, thermal, and tribological properties of these materials. This is achieved through various mechanisms, including the restriction of grain growth, hindrance of dislocations, load transfer at interfaces, and mitigation of thermal expansion mismatch. The precise reinforcement and optimization of fabrication techniques have opened up new avenues for achieving uniform nanostructure dispersion and strong interfacial bonding, leading to substantial improvements in quantitative properties. Such advancements in material science hold great promise for the development of high-performance materials with enhanced properties that are vital for various applications, including aerospace, automotive, biomedical, and beyond. The addition of low-carbon nanostructures to polymer matrix, ceramic, and biocomposite systems has also been observed to elicit noteworthy multifunctional improvements. Reinforcing collagen with CNT fibers leads to better mechanical and electrical performance compared to using collagen alone. This critical review provides an insightful and data-driven analysis of the current state of carbon nanostructure (CNTs/graphene)-reinforced metal matrix and biocomposites based on an extensive literature evaluation. The review includes an in-depth examination of the optimized synthesis and processing techniques for CNTs and graphene MMCs, highlighting the impact of reinforcement on their mechanical, thermal conductivity, electrical conductivity, and functional properties. Continued work refining fabrication methods fully leverages their potent multi-functional enhancement capabilities.

This is to certify that the thesis entitled "Development of Cu-Based Metal Matrix Composites Using Silicon Carbide, E-Glass Fiber and Multiwalled Carbon Nanotubes as Reinforcement" being submitted by Mr. Harshpreet Singh to the National Institute of Technology Rourkela, for the award of the degree of Masters of Technology (Research) is a record of bonafide research work carried out under my supervision and guidance. The results presented in this thesis have not been submitted elsewhere for the award of any other degree or diploma. This work in my opinion has reached the standard of fulfilling the requirements for the award of the degree of Masters of Technology (Research) in accordance with the regulations of institute.

This review paper investigates novel approaches to the fabrication of fiber-reinforced composites (FRCs) via additive manufacturing (AM), with a focus on improving mechanical properties in polymers, metals, and ceramics while reducing weight of the structures. FRCs have been regarded as the optimal material choice across the automobile, aerospace, and construction industries due to their exceptional characteristics, including high strength-to-weight ratio, elevated stiffness, commendable thermal stability, remarkable fatigue and impact resistance, as well as noteworthy chemical and corrosion resistance. AM plays a significant role in FRCs production by offering design flexibility, product customization, waste reduction, near net shape fabrication, cost-effectiveness, and fast prototyping. This paper initially categorizes AM of FRCs into three categories: AM of polymer-matrix, metal-matrix, and ceramic-matrix composites. These categories are further subdivided based on the types of matrix as well as fibers used. Subsequently, it emphasizes the roles of 4D printing and numerical simulation in AMFRCs. The review concludes by addressing potential applications, existing challenges, and scope of AMFRCs in future research and development.

Hybrid composites, specifically Al/SiC/Gr, are a promising area of research in material science. This work deals with the Al/SiCn/Grµ hybrid composite, which includes the additional nano silicon carbide particles (SiCn) at 2, 4, 6, 8, and 10% volume fraction (VF) and 1 and 5 % VF of micro-graphite particles. The process involves blending metal powders, cold pressing, and sintering at 620°C for 2 hours to create a specific green part. The results show that the increased volume fractions of SiC and Gr result in higher porosity, lower density and reduced wear rate compared to pure Al matrix. The microhardness values of 168, 191 HV were evinced by reinforcing with Al+6%SiC+1%Gr and Al+6%SiC+5%Gr, respectively. The highest compressive strength values of 153.38 MPa and 95.77 MPa were found in Al+6%SiC+1%Gr and Al+6%SiC+5%Gr, respectively.

Neste artigo, será feita uma investigação sobre as maneiras pelas quais questões sobre imagem técnica são tematizadas em diferentes produções artísticas, usando como corpus de análise o filme Matrix, de Lana e Lilly Wachowski, e o romance Time Out of Joint de Philip K. Dick. A partir da análise das duas obras, pretendemos discutir o crescente papel das imagens técnicas (aquelas produzidas por meio de processos químicos, elétricos e/ou eletrônicos) na configuração de noções de realidade, fazendo com que aspectos do simulacro e do hiper-real se infiltrem na percepção intersubjetiva que o indivíduo tem do mundo. Considerando a fortuna crítica sobre o assunto e do estudo do filme e do romance supracitados, indicaremos como a profusão de imagens técnicas, em especial na contemporaneidade, inaugura uma tensão entre o próprio conceito de representação e o real, problematizando questões de referência e cópia. Além disso, por meio da análise de Matrix e Time Out of Joint, veremos como obras de diferentes meios (nesse caso, o cinematográfico e o literário) tematizam esses discursos, abrindo perspectivas de entendimento para o papel e a influência da imagem técnica no terreno das artes e da cultura de massa.

An motor cylinder's pistons are a critical part. The producers are compelled to investigate using the optimal piston alloy in the combustion chambers due to intense rivalry among them. The most common materials used to make pistons are "steel, iron, and aluminium". The challenge of choosing an appropriate element for a machine part used in
a particular structural application is challenging since the engineers must take a variety of aspects into account. When selecting the best applicant fabric for a specific application, developers must take into account a variety of properties, including "mechanical, physical, magnetic, electrical, thermal and radiation, surface characteristics, machinability, material cost, reliability, durability, recyclability, impact on the environment, availability, fashion, market trends, cultural aspects, etc.".

Ultrasonic waves with a frequency of 25 KHz were used to enhance the acidic chemical recycling of tungsten heavy alloy (WHA) scrap class 2 HA175 with a typical composition of Ni-5.25 wt%, Fe-2.25 wt%, and W-92.5 wt% to recover the tungsten powder. The experiment demonstrated that the scrap sample exposed to ultrasonic waves produced a significantly higher amount of tungsten powder with a submicron particle size. The recycled tungsten powder was utilized to manufacture a new tungsten heavy alloy sample class 2 HA175 with the same alloy composition as the above. The elemental powders were mixed mechanically, cold compacted, and sintered at 1500◦C in a vacuum furnace. The microstructure, phase structure, and composition of the sintered WHAs were investigated by Scanning Electron Microscopy (SEM) and X-ray diffractometer (XRD). The recycled sample's density and hardness were higher than the original, in which the hardness increased from 312 to 340 HV, whereas the wear rate and coefficient of friction were decreased  by about 50%. The longitudinal (VL) and shear (VS) velocities for both samples were examined using ultrasonic (NDT).

Manufacturing sectors, including automotive, aerospace, military, and aviation, are paying close attention to the increasing need for composite materials with better characteristics. Composite materials are significantly used in industry owing to their high-quality, low-cost materials with outstanding characteristics and low weight. Hence, aluminum-based materials are preferred over other traditional materials owing to their low cost, great wear resistance, and excellent strength-to-weight ratio. However, the mechanical characteristics and wear behavior of the Al-based materials can be further improved by using suitable reinforcing agents. The various reinforcing agents, including whiskers, particulates, continuous fibers, and discontinuous fibers, are widely used owing to enhanced tribological and mechanical behavior comparable to bare Al alloy. Further, the advancement in the overall characteristics of the composite material can be obtained by optimizing the process parameters of the processing approach and the amount and types of reinforcement. Amongst the various available techniques, stir casting is the most suitable technique for the manufacturing of composite material. The amount of reinforcement controls the porosity (%) of the composite, while the types of reinforcement identify the compatibility with Al alloy through improvement in the overall characteristics of the composites. Fly ash, SiC, TiC, Al2O3, TiO2, B4C, etc. are the most commonly used reinforcing agents in AMMCs (aluminum metal matrix composites). The current research emphasizes how different forms of reinforcement affect AMMCs and evaluates reinforcement influence on the mechanical and tribo characteristics of composite material.

The paper reviews contemporary research in the area of hybrid composites based on zinc and aluminium alloys reinforced with SiC and graphite particles. Metal matrix composites (MMCs) based on ZA matrix are being increasingly applied as light-weight and wear resistant materials. Aluminium matrix composites with multiple reinforcements (hybrid AMCs) are finding increased applications because of improved mechanical and tribological properties and hence are better substitutes for single reinforced composites. The results of research show that the hybrid composites possess higher hardness, higher tensile strength, better wear resistance and lower coefficient of friction when compared to pure alloys.

In the paper were shown the test results of tribological characteristics of hybrid composites with alloy base A356 reinforced by SiC and graphite. Hybrid composites are obtained by compo casting procedure. Tribological tests are realized on tribometer with block on disc compact pair in Tribological Center of Faculty of Engineering in Kragujevac. The tests were done for different normal load values, sliding speeds, sliding distance, with and without lubrication. Hybrid composite with 10% SiC and 1% graphite was used as a material. The main parameter analyzed in the paper is coefficient of friction obtained in the conditions with and without lubrication.

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The prominent demerit of aluminum as a food grade material is its low tensile strength and impact tolerance with greater liability to break compared to other common food grade metals. It is reaffirmed that aluminum can corrode appreciably in alkaline environments with pH greater than 9 and exacerbate its weakness in strength and frequent intake of its ions along with food into the human body due to corrosion or other means can be health-hazardous. Aluminum containers were seen to be in use for preparing and serving various menus from the general Nigerian diet to about 1000 cadets on daily basis at Nigerian Defence Academy (NDA) cadets' mess. The menus and various ingredients used for them amidst the general mess environment were seen to be inevitable of ability to corrode the containers. The paper was a search through accelerated corrosion test to understand whether some of the commonly prepared and served menus at the mess namely; Eba, fried rice, Egusi soup, tomatoes stew, Alayafu vegetable dressings, and their possible different combinatorial admixtures amidst any alkaline environment had severe corrosion effects on the tensile strength of the containers. 64 ASTM standard tensile samples of aluminum 6063 as a commonly used food grade alloy for such containers were procedurally produced and prepared for the study. 62 of the samples were subjected in pairs to some similar and alkaline treatments that mimicked alkaline environment corrosivity extremity of each menu to the containers. Thereupon, the samples were tested of their ultimate tensile strengths (UTS) and results collated and reported as the respective average pair values. Analysis of the reported results relative to that of the control sample pair showed negligibly small tensile strength reductions of 0.00027% to 0.00135%. Further analysis using literature facts understandably indicted that the menu samples amidst the mess environment have negligible effects on corrosion and tensile strength of the containers and health of the cadets.

In this research, the microstructure and mechanical properties of Al-15Si-10Zn-xZrO 2 (x = 5, 7 and 10 wt.%) composites synthesized by the stir-casting process have been investigated. The matrix and composite samples were characterized using an X-ray diffraction test (XRD) and their microstructures were studied using optical microscopy and scanning electron microscopy (SEM). The microstructure of different phases was analyzed using energy-dispersive spectroscopy (EDS). The microstructure of the Al-15Si-10Zn/ZrO 2 composites consisted of coarse primary Si, needlelike eutectic Si, and Zn-rich phases, with ZrO 2 reinforcement particles distributed homogeneously in the composites. The micro-hardness and tensile properties of the matrix and composites were determined at room temperature. The results show significant improvements in the micro-hardness and tensile strength of the composites compared to the matrix alloy. The micro-hardness of the stir-cast composites increased by 24%, 44%, and 58% in the 5, 7, and 10 wt% ZrO 2 reinforcement composites, respectively. The ultimate tensile strength (UTS) of the 5, 7, and 10 wt% ZrO 2 composites increased by 17%, 30%, and 44%, respectively, compared to the matrix alloy. The increased content of ZrO 2 resulted in an increase in hardness, ultimate tensile and yield strengths and a decrease in ductility.

An motor cylinder's pistons are a critical part. The producers are compelled to investigate using the optimal piston alloy in the combustion chambers due to intense rivalry among them. The most common materials used to make pistons are "steel, iron, and aluminium". The challenge of choosing an appropriate element for a machine part used in a particular structural application is challenging since the engineers must take a variety of aspects into account. When selecting the best applicant fabric for a specific application, developers must take into account a variety of properties, including "mechanical, physical, magnetic, electrical, thermal and radiation, surface characteristics, machinability, material cost, reliability, durability, recyclability, impact on the environment, availability, fashion, market trends, cultural aspects, etc.". This selection procedure is laborious and time-consuming. " Elegance, sentiments, and userfriendly design" are now the primary factors in today's choice of materials. In this study, eight potential piston composites' effectiveness is assessed using eight criteria. The best composites among the resources under consideration were selected using the "WSM method (Weighted Sum Method)", a multi-criteria choice procedure because no one material would merely fulfil all the needed features. The ranks of "Aluminum 2618-T61 is 3, Aluminum 4032-T6is 5, Aluminum A360.0-F die casting alloy is 6, Aluminum 6061-T6 is 4, Grey cast iron is 7, AISI 8660 steel is 2, AISI 4140 steel is 1 and Ductile iron grade 65-45-12is 8". The order preferred for materials is "AISI 4140 steel > AISI 8660 steel > Aluminum 2618-T61 > Aluminum 6061-T6 > Aluminum 4032-T6 > Aluminum A360.0-F die casting alloy > Grey cast iron > Ductile iron grade 65-45-12". "AISI 4140 steel, AISI 8660 steel and Aluminum 2618-T61" were discovered to be the best materials among the selected alternate materials, as per the Weighted Sum Method (WSM) technique. The people who make decisions' desire for choosing the best conveyor was significantly influenced by " high hardness, fatigue strength and modulus of elasticity, and low material cost of materials.

Effect of titanium addition on the dry sliding wear behaviour of hypereutectic Al-Si alloys are investigated at elevated temperatures. Wear tests are conducted for varying normal pressure from 0.20 N/mm 2 to 0.98 N/mm 2 , for varying sliding velocity from 0.94m/s to 3.77 m/s and varying sliding distance from 282.74 m to 1696.46 m. In this present investigation, hyper eutectic aluminium based alloys containing 13% and 20% weight of silicon; with addition of titanium is synthesized using casting method. Wear behaviour is studied by using computerized pin on disc wear testing machine. Worn surfaces were examined and analysed by scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDS). The wear results show that the wear rate increases with increase in normal pressure (0.20 N/mm 2 to 0.98 N/mm 2) and sliding distance (282.74 m to 1696.46 m), but wear rate decreases with increase in sliding velocity from (0.94 m/s to 3.77 m/s). The addition of titanium to Al-Si a...

In this study, two erosion protection MMC coatings with WC particles were deposited by the plasma transferred arc (PTA) welding. One of the coatings with tungsten carbide WC in the NiBSi matrix (WC/NiBSi), and the second coating WC in NiCrBSi matrix (WC/NiCrBSi) was deposited by the flame spray process on the same substrate material S235JR steel. Experiments were performed using a gas blast sand erosion test facility with high-velocity erodent particles impact (approximately 100 m/s) at different particle impact angles (20°-45°), with an objective to study erosion wear characteristics and mass loss of two MMC coatings. Microstructural characterization of MMC coatings was done by scanning electron microscope equipped with energy-dispersive X-ray spectroscopy, whereas X-ray diffraction analysis was used for identification of present phases. The hardness of coatings was determined by Vickers hardness measurements. WC/ NiBSi obtained by the PTA process shows superior hardness and erosion properties.

High stress abrasive wear behaviour of Al-Zn alloys containing high zinc concentration at varying applied load and abrasive size has been studied through two-level full factorial design approach. The upper level of zinc concentration, applied load and abrasive size is selected as 70 wt%, 7 N and 180 m, respectively. The lower level of zinc concentration, applied load and abrasive size is taken as 30 wt%, 1 N and 60 m, respectively. The linear regression equation, for the wear rate (W r ) as a function of these parameters (applied load, abrasive size and Zn-concentration) and their interaction, has been developed as: where C, L and A are coded values of Zn-concentration, applied load and abrasive size, respectively, and the multiplication factor for the wear rate and the coefficients is 10 -11 m 3 /m. The positive value of the coefficients associated with coded values of various parameters and their interactions in the above equation suggests that abrasive wear rate increases with zinc concentration, abrasive size and applied load. The validity of the developed equation has been checked with experimental values at randomly selected experimental parameters within the selected experimental domain. The results have been explained with selected worn surfaces and debris analysis.

This NIRT research program is to advance both the fundamental understanding and knowledge of ultrasonic cavitation based solidification processing of complex bulk Mg MMNC materials/components and their processing/structure/property relationships. Cast bulk Mg alloy matrix nanocomposites can have a widespread impact on the automobile and aerospace industries by significantly improving the vehicle energy efficiency and performance. One of the major tasks of this NIRT program is to characterize the micro/nano structure of the resultant nanocomposites. The dislocation structure in the matrix around nanoparticles will be examined to understand the mechanism of strengthening by nanoparticles.

Tribology experiments have a crucial importance in order to verify results of simulations and calculations and sometimes it is the only way to solve important problems and tasks. Numerous requirements in experimental investigations now days need a new approach in data acquisition (DAQ) tools and methods, where time and mobility are taking significant place. Last years LabVIEW software made a great expansion in industrial measurement applying and virtual instrumentation in data acquisition. The aim of this paper is to present some advantages of standard and portable DAQ Equipment with LabVIEW software and to show their application in some common tribology experiments. This equipment is also excellent tool in condition monitoring of mechanical systems from the aspect of tribological parameters. By comparing classical experimental techniques and simulations with Lab VIEW possibilities in combination with portable hardware modules, this paper will serve as a support for the development of new approach in tribology experimental investigations and their involving in general concept of condition monitoring. It is obvious, that the ambitious aims of this concept has a multidisciplinary approach by integrating this advance research and education tool of experimental design in mechanics, fluid dynamics, micromechanics etc.

he main objective of this study is to investigate, for the first time, the feasibility of 3d printing a continuous carbon fiber (CCF) reinforced metal matrix composite using a cost-effective material extrusion (MEX) technology. Notably, this paper presents a detailed analysis of the microstructure and mechanical and physical properties of a bronze matrix composite reinforced with CCF. The results reveal that CCF significantly impedes the expected densification levels of the composite's structure, causing extensive gaps between the bronze particles. However, despite the high porosity level, the composite's electrical conductivity remains relatively high, demonstrating the limited negative impact of the CCF material on the composite's conductivity. Moreover, mechanical evaluations were performed through 3-point bending and tensile tests, highlighting the composite material's advantages and limitations. The results show that the composite material exhibits an improved yield stress of 76 %, increased ultimate tensile strength of 20 %, and an extended fracture strain of 30 %. However, the flexural strength decreases by 23 % due to the presence of massive gaps formed by CCF.

Nowadays sandwich structures are used as bird shields to protect aircraft nose bulkhead. They are usually made of aluminum honeycomb and sheets. In order to optimize mass, cost and efficiency of such bird shields, aircraft manufacturers want to explore new materials and designs. In this context, this work aims at exhibiting influences of material and design parameters on the bird strike response of sandwich structures. Based on previous finite element calculations that enabled to determine the most influential parameters, a design of experiment has been defined to span a parameter space in 4 dimensions, namely the thickness of the front skin, the thickness of the core, the yield stress of the front skin and the crushing stress of the core. 13 configurations of sandwich structures are then tested according to this design of experiment. These samples are 800 mm x 800 mm square sandwiches simply supported on a rigid square frame. The impactor is a 1.6 kg gelatin bird substitute, thrown...

The process of machining CFRP composites presents unique challenges, particularly in the context of WEDM. The inherent properties of CFRP composites, such as their low electrical conductivity, anisotropic nature, and heterogeneous composition, require further research to enhance their machinability through WEDM techniques. This study examines the enhancement of kerf characteristics such as kerf width (W k), delamination factor (DF K), and cutting speed (CS K) in thin woven 0°/90° CFRP composites using high-speed WEDM. A Taguchi L 16 experimental analysis was employed to analyze the impact of key process parameters, including pulse-on (P on), pulse-off (P off), and input current (I), in conjunction with CFRP parameters such as the CFRP thickness (T) and cutting direction on the kerf characteristics. The CFRP thickness ranged from 0.5 to 2.0 mm, and the cutting directions studied were horizontal and inclined 30° cuts. A multiple-response optimization strategy using the CRITIC-WASPAS approach coupled with a particle swarm optimization (PSO) algorithm were applied to identify the ideal process combination for various CFRP thicknesses. The findings indicated that the CFRP thickness, pulse-off time, and input current are the most statistically significant factors influencing the overall kerf characteristics. The cutting direction has a negligible effect on the kerf width but has conflicting effects on the delamination factor and cutting speed. Specifically, a horizontal cut decreases delamination, whereas an inclined 30° cut is preferable for achieving higher cutting speeds. For precise kerf cutting, optimal process combinations were determined: P on (30 µs), P off (30 µs), and I (ranging from 4 to 5 A) for 0.5 mm CFRP thickness, and P on (30 µs), P off (15 µs), and varying input currents of 4 A, ranging from 4 to 3 A, and 3 A for CFRP thicknesses of 1.0, 1.5, and 2.0 mm, respectively. Article Highlights • HS-WEDM delivers excellent results in attaining precise kerf quality for thin CFRP composites. • The thickness of the CFRP composite significantly influences the overall kerf characteristics when using HS-WEDM. • The application of CRITIC-WASPAS and PSO enhances the kerf quality by 8% to 22% across various CFRP thicknesses.

In this research, mechanical alloying was used to synthesize ultrafine grained AA2024 and AA2024-B4C powders in an attrition mill under argon atmosphere up to 50 h with the rotational speed of 400 rpm. In order to determine the grain size of the matrix, X-Ray diffraction test and Williamson–Hall method was used. After mechanical alloying, hot pressing and hot extrusion were used for densification of powders. The microstructure and mechanical behavior of hot extruded samples were characterized by scanning electron microscopy (SEM), tension and compression and hardness tests. The microstructure of samples showed that the CuMgAl2 precipitate is present. Furthermore, the distribution of these precipitates in nanostructured samples was more uniform and their content was greater. The results of mechanical tests indicated that the strength and hardness of AA2024 alloy after mechanical alloying and addition of B4C particles increases for 64 and 49%, respectively. In other words, the AA2024-B4C nanocomposite showed the highest strength and hardness, however, its elongation was the lowest.

In this study, co-precipitation processing route has been opted to prepare the ZTA composites. The well homogenized powders are compacted in a circular shape die-punch arrangement using hydraulic press. The mechanical properties of developed composites are evaluated on Vickers testing machine. In this study, a wide range of test load (0.5-50 N) has been applied on the samples to see it's the effect on hardness. A significant decrease in the value of hardness and fracture toughness has been observed with increasing load. An interesting result has been observed beyond 25 N loads, where stagnation in the said properties is observed. After evaluation of mechanical properties the ZTA composites are used to investigate the tribological properties. A comparative study has been made between alumina and ZTA ceramics at a load of 20 N with sliding velocity of 0.5 m/s. The observed results show an improvement of 57.8% in case of specific wear rate, whereas 19.78% improvement has been achieved in case of coefficient of friction for ZTA ceramics as compared to alumina ceramics. The improvements in tribological properties are attributed to the soft phase of zirconia reinforced inside hard matrix of alumina which provides a toughening effect.

Wire Electrochemical Micromachining is a relatively new method of machining using electrochemical dissolution; it utilizes the principle of electrolysis and uses a micro-wire for metal removal to produce micro metal parts. Since there is no tool wear, a thinner wire can be used in this process. In the present study, Wire electrochemical machining input parameters are optimized using Taguchi approach for maximum metal removal rate. In this study continuous DC power supply is used for metal removal and the tool is made up of copper wire. After analysis, the optimum parameter range came out to be 200 g/l of electrolyte concentration and 24 V of machining voltage. The electrolyte used is aqueous Sodium Chloride solution.

In this study, co-precipitation processing route has been opted to prepare the ZTA composites. The well homogenized powders are compacted in a circular shape die-punch arrangement using hydraulic press. The mechanical properties of developed composites are evaluated on Vickers testing machine. In this study, a wide range of test load (0.5-50 N) has been applied on the samples to see it's the effect on hardness. A significant decrease in the value of hardness and fracture toughness has been observed with increasing load. An interesting result has been observed beyond 25 N loads, where stagnation in the said properties is observed. After evaluation of mechanical properties the ZTA composites are used to investigate the tribological properties. A comparative study has been made between alumina and ZTA ceramics at a load of 20 N with sliding velocity of 0.5 m/s. The observed results show an improvement of 57.8% in case of specific wear rate, whereas 19.78% improvement has been achieved in case of coefficient of friction for ZTA ceramics as compared to alumina ceramics. The improvements in tribological properties are attributed to the soft phase of zirconia reinforced inside hard matrix of alumina which provides a toughening effect.

The fatigue behaviour of Aluminium alloy (LM4) � Alumina silicate (Al2O3SiO2) particulate composite is investigated in comparison with unreinforced LM4 aluminium alloy in this work. Four different volume fractions (0.05, 0.15 and 0.20) of Alumina silicate particulates of size 10 m are introduced into the melt. The fabrication of specimen is carried out by stirring followed by squeeze casting. The fatigue strength tests are conducted on these specimens with a stress ratio (R) of 0.1. The composite specimens have longer fatigue lives than matrix alloy in lower stress state and exhibited a reduced fatigue lives at elevated stress state irrespective of their reinforcement volume fraction.