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Electrical discharge machining has emerged as one of the most accepted non-traditional machining methods that have the capability of attaining complex shapes and better feature size in difficult-to-machine materials. In this article, an advanced review of conventional electrical discharge machining and micro–electrical discharge machining of difficult-to-machine materials, such as nickel and its alloys, titanium alloys, stainless steel (SUS 304) and advanced ceramics, has been presented. The review begins with an introduction to the conventional electrical discharge machining and micro–electrical discharge machining processes, followed by classifications and a brief discussion on different aspects of micro-manufacturing methods. The current research trends and developments, research gaps and challenges of the conventional electrical discharge machining and micro–electrical discharge machining of nickel and its alloys, titanium alloys (Ti6Al4V), stainless steel and advanced ceramics are also discussed in depth. A brief note on future research trends, based on the available literature, has been included in the last section.

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High performance epoxy based EMI shielding hybrid composites were prepared and characterized for their mechanical, magnetic, and Electromagnetic Interference (EMI) shielding behavior. The aim of this research was to enhance the electromagnetic interference shielding effect of a nanocomposite at high frequency with good mechanical strength. The shielding effectiveness of the epoxy composite was improved via the addition of E-glass/silver nanoparticle and nickel nanosheets. The reinforcements were silane surface modified to enhance the adhesion and dispersion of reinforcements with matrix. The composites were prepared via hand layup process using glass fiber, silver nanoparticle, and Ni nanosheets followed by room temperature curing. The characterization of hybrid composites was done in accordance with ASTM standards. The results revealed that the Ag and Ni along with E-glass fiber improved conductivity, permittivity, and permeability of epoxy composite. Similarly, the mechanical behavior of nanocomposite was found to be increased for tensile, flexural, and Izod impact toughness. Moreover, a maximum wave attenuation of -48 dB was observed for 3-mm thick composite shielding material in "J" band frequency. These mechanically sound high EMI shielding lightweight polymer composites could be used as potential material for aerospace, defense, tele-communication, and satellite data transfer applications. Besides the reduction of EMI effect between electronic gadgets could improves the utility and life span of electromagnetic devices and gadgets in several engineering applications. K E Y W O R D SEMI shielding, mechanical properties, Ni nanosheet, polymer matrix composite, silver NPs | INTRODUCTIONElectromagnetic (EM) shielding effectiveness (SE) is one of the helpful solution to minimize EMI problems and to warrant the safety of the electronic systems. [1,2] Metals are utilized in EM shielding implementations because they are conductive and liable to reflect forthcoming EM waves. [3,4] While, considerable issues appear concerning

The present work aims to study the moisture uptake and thickness swelling behaviour and its effect on tensile and flexural properties of Luffa cylindrica epoxy composite. Characterizations of the luffa fibre surface were carried out by energy-dispersive X-ray spectroscopy and Fourier transform infrared spectroscopy. Composites were casted with single, double and triple layer of Luffa cylindrica fibre reinforced with epoxy resin by general hand-layup technique. Moisture uptake tests of composites were conducted by subjecting the composite samples in three different environments such as distilled water, saltwater (5% NaCl solution) and sub-zero temperature (–25°C). The diffusivity constant, thickness swelling rate parameter (KSR) and equilibrium moisture content were found out. The result indicates that moisture absorption pattern follows the Fickian diffusion behaviour for composites in all three environments. As the fibre layer increases, the percentage of moisture uptake increased due to high cellulose content. The mechanical properties of the composites were decreased with moisture absorption. Scanning electron microscope study was carried out to study the fracture behaviour of tested samples.

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