The carbon fiber reinforced polymer matrix composites play an important role in many applications, due to their high strengths and moduli. Hence, this present study focuses on evaluation of mechanical properties of three dimensional (3D)-printed carbon fiber/polylactic acid (CF/PLA) composites, using fused deposition modeling (FDM) technique. The composites were prepared with different slicing parameters: layer heights or thicknesses (0.08, 0.25 and 0.64 mm), infill densities (20, 40, 60 and 80%) and layer patterns (rectilinear, triangular and hexagonal). The 3D-printed CF/PLA composite samples were subjected to tensile, flexural and interlaminar shear strength (ILSS) tests to assess the influence of the aforementioned process parameters on their mechanical characteristics. Further investigations were carried out to evaluate the effect of surface roughness of the samples on their mechanical properties. From the test results obtained, it was evident that both rectilinear and hexagonal patterns exhibited better mechanical properties at infill density and layer thickness of 60% and 0.64 mm, respectively. The fractured samples were examined, using scanning electron microscopy (SEM). The images depicted that lesser layer thickness produced poor CF/PLA interfacial bonding/adhesion and major failure mode was traced to fiber pull-out.Therefore, engineering application of the various 3D-printed CF/PLA composite samples evidently depends on their slicing parameters, as studied.

In recent years, stringent requirements of material quality in automotive and aerospace industries have necessitated the development of lightweight aluminum alloys. In this context, it is known that the metal–matrix composites offer a spectrum of advantages that are important for their selection and use as structural materials. A few such advantages include the combination of high strength, high elastic modulus, high toughness and impact resistance, low sensitivity-to changes in temperature or thermal shock, high surface durability, low sensitivity to surface flaws, high electrical and thermal conductivity, minimum exposure to the potential problem of moisture absorption resulting in environmental degradation, and improved fabricability with conventional metal working equipment Metal matrix composites (MMC) are generally produced either by liquid metallurgy or powder metallurgy techniques. Stir casting is one of the most inexpensive tools for the production of particulate metal matrix composites . It is simplest and most commercially used technique for casting MMCs. This involves incorporation of ceramic particulate into liquid aluminum alloy in molten state and allowing the mixture to solidify. Here, the crucial thing is to create good wetability between the particulate reinforcement and the liquid aluminum alloy. In this proposed work , composites of Al7075 with SiC were fabricated using Stir casting method by using both upward and downward pouring methodology .The main objective of this research work are to achieve uniform distribution of SiC particles in the aluminum alloy matrix , characterization and analysis of mechanical properties of composites formed . Experiments were carried out with different stirring speeds and specimen of different %wt of SiC were cast . Microstructure , Tensile strength and hardness values were found by conducting the corresponding tests and results were analyzed and compared . Keywords - MMCs , Stir casting , Wire cut EDM , SiC reinforced metal matrix composites

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The weight of the car material plays an important role in its performance in terms of fuel efficiency, speed and smoke emission. Especially in hybrid electric vehicles, lightweight materials are important for balancing the weight of its electrical components and also to enhance vehicle speed on account of its comparative low mileage. Nowadays, aluminium, magnesium and Carbon Fibre Reinforced Composites (CFRP) were introduced in making of car body panels since those materials can improve its performance. Yet the material costs, fibre orientation and fabrication techniques in case of CFRP in mass production remains a question. Also, the interior of the car panels was filled with vibration barriers or isolators with considerable thickness which can also add weight to the car. Hence a sandwich structure is presented in this work where the polyurethane foam of higher thickness (core) is bonded between two thin metallic face sheets (skin). The polyurethane foam was chosen as the core because of its low density, porosity and viscoelastic behaviour where it can provide better damping capabilities. Hence, the foam can also help in reducing the volume of internal vibration isolators. Since the car bonnet receives the vibration from sources like aerodynamic exposure to air during travel and mechanical movements within the vehicle (engine operation), it was chosen as the subject for vibration analysis.

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