Metal matrix composite

The Aluminium Metal Matrix Composites (AMMC's) provides high strength and stif ness to the metals, so it is utilised in the applications like robots, high speed rotating shafts, high speed machinery etc. The AMMCsrequires a fabrication process to improve its mechanical properties. Some of the previous researches has been involved in applying the reinforced AMMC’s in Electrical Discharge Machining (EDM) to analysis its characteristics. In this research study, the hybrid AMMC’s is used in the EDM process to analysis the optimum input conditions. The combination of Al7075, Boron Carbide (3%), and Zirconium dioxide (15%) are utilized for analysing the EDM process. The Stir Casting method is used for fabrication of hybrid AMMC’s. In addition, Orthogonal array is used to analyse the parameters; Tool Wear Rate (TWR), Surface Roughness (SR) and Maximum Material Removal (MRR) rate on the basis of voltage (V), current (I), pulse-on time () and pulse-of time (). By varying the input parametric values like ,,  and , the output performance measures; TWR, SR and MRR are analysed in the experimental section. The experimental analysis shows that the optimal value of the input parameter is V is 60, I is 8.242, TON is 5.01 and TOFF is 6 and has the output parameter of MRR is 0.4613, TWR is 0.0139 and SR is 2.46. The experimental investigation shows that current is most influence parameters af ects the MRR, TWR and SR

A finite difference technique is developed to predict the second stage creep displacement rates and stress analysis of a short fiber metal matrix composite subjecting to a constant axial load through a micromechanical approach. The technique is capable to take into account the presence of interfacial debonding as one of the main factors affecting the creep performance of short fiber composites. The exponential law is adopted to describe the matrix creep behavior. Also, a model for prediction of interfacial debonding at fiber/matrix interface is developed using a stress based method. The obtained results could greatly help to better understand the flow pattern of matrix material and the load transfer mechanism between fiber and matrix with and without the presence of interfacial debond. The predicted strain rate by the proposed approach exhibits good agreement with the experimental results.

Mechanical alloying has been widely utilized to break down the clustered CNTs for incorporation in the metal matrix composites. However, the breakage of CNTs during the ball milling process degrades their effectiveness. Due to the challenges in collecting the CNTs for measurement, quantitative study of CNT breakage has been difficult. In this study, the CNTs with Al6061 powder were mechanically alloyed with high energy milling equipment. The CNTs from the surface of mechanically alloyed particles were collected and measured. Due to the difficulty in obtaining the CNTs embedded inside the particles, a mathematical model has been developed to predict the overall CNT length distribution in the composite. Significant CNT breakage occurred during the initial phase of the mechanical alloying due to the crushing of the clusters. The model predicted that no further change occurred in the overall CNT length during time greater than 1 h of mechanical alloying because most of the CNTs had already become embedded within the particles and were thus protected from further milling media impacts. A faster dispersion of CNTs and lower particle fracturing rate may help preserve the original CNTs.

The preparation of aluminum metal matrix composites is significant because such composites have diverse applications in the automobile and aeronautics industry. Even though many researchers have worked in the area for preparing composite materials. out different process very few of them have got success in preparing composite materials ,out of them powder metallurgy technique and stir casting technique are two of them. These methods are adapted for preparing composite material in this paper. Experiments were conducted on Aluminium +Al2O3 and Aluminium+ Al2O3 + Pb as metal matrix composites. By considering selected variations in the% compositions of lead and flyash in Aluminium + Al2O3 (alumina). Samples were prepared and tests are conducted for hardness ,compression strength, tensile strength and Impact strength. Results are compared and measured with in these two methods to justify the process for composite preparation. Keywords: Powder metallurgy technique, stir casting process, metal matrix composite, hardness number, compression strength, tensile strength, impact strength Highlights:-Preparation of composite material by powder metallurgy technique and stir casting process •-Studying the hardness number and compression strength of composite based on % of composition of flyash and lead. _______________________________________________________________________________________________________

Silicon carbide reinforced aluminum alloy composite materials produced by casting methods are increasingly used in many engineering fields. However, these materials suffer from poor distribution of the reinforcement particles in the matrix and high content of porosity. The effect of subsequent cold rolling process with different reductions on the porosity, microstructure and mechanical properties of cast Al6061/10 vol.% SiCp composite was investigated in this study. Composites fabricated by compocasting method were rolled at five different reductions of 30, 60, 75, 85 and 95%. The rolled specimens exhibited reduced porosity as well as a more uniform particle distribution when compared with the as-cast samples. Microscopic investigations of the composites after 95% reduction showed an excellent uniform distribution of silicon carbide particles in the matrix. During cold rolling process it was observed that the tensile strength and ductility of the samples increased by increasing the reduction content. After 95% reduction, the tensile strength and elongation values reached 306.7 MPa and 7.9%, which were 4.6 and 3.3 times greater than those of the as-cast composite, respectively.► When the reduction increased during rolling process, the porosity of the composites decreased. ► Increasing the reduction ratio greatly improved the uniformity of SiC particles. ► The tensile strength of the composites increased by increasing the reduction ratio. ► By increasing the reduction ratio, the elongation of the composites improved.

Aluminum Silicon Carbide (AlSiC) metal matrix composite (MMC) materials have a unique set of material properties that are ideally suited for all electronic packaging applications requiring thermal management. The AlSiC coefficient of thermal expansion (CTE) value is compatible with direct IC device attachment for the maximum thermal dissipation through the 170 – 200 W/mK thermal conductivity value material. Additionally, the low material density of AlSiC makes it ideal for weight sensitive applications such as portable devices. The AlSiC material and functional electronic packaging geometries are produced using the Ceramics Process Systems Corporation's QuickSet™/QuickCast™ net-shape (without machining) fabrication process. Additionally, functional packaging features such as feedthrus, sealrings and substrates are incorporated in AlSiC during fabrication using the CPS Concurrent Integration™ technique eliminating the need for the traditional assembly and brazing (or soldering) o...

This paper deals with the design of solid rocket mainly consists of determining the thickness of motor casing which includes the domes at head end, nozzle end and flange for bolted joints. Modeling of solid rocket motor components and its assembly is done in CATIAV5R19. Stress distributions are due to the effect of working stress developed in the components. The maximum working stress is compared with allowable yield stress of the material. Final conclusion brings out a well designed solid rocket motor for the effective storage of propellant for obtaining the required impulse. 2D Axi-Symmetric structural analysis for solid propellant rocket motor Casing is performed to determine the stress level of all components using ANSYS 12.0..

Titanium alloys and their composites have the potential to reduce truck disc brake component weight and improve their resistance to road-salt corrosion. A titanium alloy rotor can weigh approximately 37% less than a conventional cast iron rotor with the same dimensions, while offering good high-temperature strength and much better resistance to corrosion from road-deicing salts. Friction coefficients and temperature rise

This paper aims, Design and Analysis of Liquefied Petroleum Gas (LPG) cylinders made of Steel. LP-gas inside a container is in two states of matter, liquid and vapour. The liquid portion of container is in the bottom and the vapour is in the uppermost part of the vessel. Liquefied Petroleum (LP) Gas is stored and handled as a liquid when under pressure inside a LP-Gas container. When compressed moderately at normal temperature, it becomes liquid. When gas is withdrawn, the pressure drops and the liquid reverts to gas. This means that it can be transported and stored as liquid and burnt as gas. A number of cases are considered to study the stresses and deformations due to pressure loading inside the cylinder. First, the results of stresses and deformation for steel cylinders are compared with the analytical solution available in literature in order to validate the model and the software. A variation of stresses and deformations throughout the cylinder made of steel is studied. In this the cylinder is designed in Pro-E WILDFIRE to study the stresses and deformations of the cylinder. And it is converted to Pro-E model to ANSYS to know variations of the steel cylinder when it is under some conditions.

There are many factors which influence the incorporation of particulate in metal matrix composites (MMCs). This paper presents work which examines the effect of viscosity during Al–SiC MMC production. Processing periods (up to 65 min), stirring speeds (50–500 rpm), and re-inforcement sizes (13–100 μm) for two different viscosity levels (1 and 300 mPa s) were investigated. Computer simulations, room temperature analogue fluid simulations, and MMC castings were performed. Volume fraction results of SiC at different locations within the fluids were assessed by each of these methods and compared. From these tests, a stirring speed of 200 rpm for the lower viscosity fluid and 300 rpm for the higher viscosity fluid were found to be best in order to produce uniform distributions of SiC. In order to obtain a uniform re-inforcement distribution in the lower viscosity system, stirring periods were found to range from 14 to 170 s and for the higher viscosity system from 540 to more than 3920 s. Fully uniform suspensions remained for just a couple of seconds in the lower viscosity system compared to about an hour for the higher viscosity system. The modelling approach chosen was found to be useful in predicting settling behaviour in the semi-solid metal.

In this investigation, the effect of wire electrical discharge machining (WEDM) parameters such as pulse-on time (T ON), pulse-off time (T OFF), gap voltage (V) and wire feed (F) on material removal rate (MRR) and surface roughness (R a) in metal matrix composites (MMCs) consisting of aluminium alloy (Al6063) and silicon carbide (SiCp) is discussed. The Al6063 is reinforced with SiCp in the form of particles with 5%, 10% and 15% volume fractions. The experiments are carried out as per design of experiments approach using L9 orthogonal array. The results were analysed using analysis of variance and response graphs. The results are also compared with the results obtained for unreinforced Al6063. From this study, it is found that different combinations of WEDM process parameters are required to achieve higher MRR and lower R a for Al6063 and composites. Generally, it is found that the increase in volume percentage of SiC resulted in decreased MRR and increased R a. Regression equations are developed based on the experimental data for the prediction of output parameters for Al6063 and composites. The results from this study will be useful for manufacturing engineers to select appropriate WEDM process parameters to machine MMCs of Al6063 reinforced with SiCp at various proportions.

One of the great challenges of producing cast metal matrix composites is the agglomeration tendency of the reinforcements. This would normally result in poor distribution of the particles, high porosity content, and low mechanical properties. In the present work, a new method for uniform distribution of very fine SiC particles with average size of less than 3 μm was employed. The key idea was to allow for gradual in situ release of properly wetted SiC particles in the liquid metal. For this purpose, SiC particles were injected into the melt in three different forms, i.e., untreated SiCp, milled particulate Al–SiCp composite powder, and milled particulate Al–SiCp–Mg composite powder. The resultant composite slurries were then cast from either fully liquid (stir casting) or semisolid (compocasting) state. Consequently, the effects of the casting method and the type of the injected powder on the microstructural characteristics as well as the mechanical properties of the cast composites were investigated. The results showed that the distribution of SiC particles in the matrix and the porosity content of the composites were greatly improved by injecting milled composite powders instead of untreated-SiC particles into the melt. Casting from semisolid state instead of fully liquid state had similar effects. The average size of SiC particles incorporated into the matrix was also significantly reduced from about 8 to 3 μm by injecting milled composite powders. The ultimate tensile strength, yield strength and elongation of Al356/5 vol.%SiCp composite manufactured by compocasting of the (Al–SiCp–Mg)cp injected melt were increased by 90%, 103% and 135%, respectively, compared to those of the composite manufactured by stir casting of the untreated-SiCp injected melt.► SiCp distribution was greatly improved by injection of milled composite powders. ► SiCp distribution was further improved by casting in semisolid state. ► The average SiCp size was greatly reduced by injection of milled composite powders. ► Porosity of the samples was decreased by compocasting and composite powder injection. ► The mechanical properties of compocast (Al–SiCp–Mg)cp composite were greatly increased.

This study presents a finite element method optimization strategy to enhance the solidification of molten aluminum alloy in the high pressure die casting (HPDC) process for the production of bulk metal matrix composites. A computational fluid dynamics approach based on the explicit volume fluid multiphase (EVFM) model was applied in the ANSYS FLUENT software environment to analyze the effect of pressurized melt infiltration and thermal loading on deformation, heat flux variations, and solidification profiles during solidification processing of aluminum alloy composite in a HPDC die of varying thicknesses, ranging from 3–24 mm. The associated turbulence was accounted for by the k-ϵ model. The solidification mechanisms were characterized for the performance of the optimal die configuration. The results indicate that the resistance to deformation was not significant for die thicknesses within the 5–15 mm range but increases sharply at a constant rate as the die thickness exceeds 15 mm. The heat transfer characteristics for the 15–21-mm die are considered as optimal for controlled melt solidification. The solidification profiles suggested that heat flux variations were most critical for the 3, 6, and 9-mm die thicknesses, while the capacity to dissipate heat at a constant rate was achieved for die thicknesses of 12, 15, and 18 mm. The thermal analysis on the optimal die configuration indicates the conditions under which the formation and growth of microconstituents would occur during the solidification process. The experimental validation suggested that the die thickness of 18–20 mm has the most significant implication for design. The mechanical properties of the hybrid composite were found to vary nonlinearly with applied pressure, while indicating an enhancement for the elastic plastic properties within the range of 70–90 MPa.