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Recent developments in material science have concentrated not only on the improvement in mechanical properties, but also on the machinability that was difficult for system profiles. The present research explains the machinability assessment of the part of the sintered powder metallurgy using an electric discharge machining. The ferrous clay matrix preparations are constructed from iron–carbon–copper material and bentonite clay. The selected input parameters for the measurement of machinability are wt. % of clay, current (A), pulse on time (µs) and voltage (V), whereas the electrode wear rate, material removal rate and surface roughness (Ra) are considered as performance features. Results show that the performance parameters have been optimized at three different parametric conditions. Further, to obtain single optimum condition the hybrid GRA-TOPSOS methodology has been implemented for maximum MRR with minimum EWR and low surface roughness. The single optimum condition has been found at 5% clay, current 7 A, voltage 49 V and pulse on time 400 µs. The study of micro-structure and chemical composition of machined surfaces has been carried out using scanning electron microscopy with X-ray diffraction and energy-dispersive spectrometry analysis, respectively. The SEM exposes the less recast layer and micro-cracks during electrical discharge machining of ferrous clay composite. [ABSTRACT FROM AUTHOR]

In PM/EDM, it is known that when used electrically conductive powders, highly homogeneous alloyed layers can be formed where the gap extends slightly more than using non-conductive powders and regulates spark discharge and machining voltage more uniform. Boron element is non-conductive but when alloyed with steel, materials with high abrasion and corrosion resistance are obtained. In this study, the effects of boron oxide powders addition into dielectric fluid on microstructure and hardness of steel workpiece in electrical discharge machining (EDM) were investigated. For this purpose, by using a prismatic steel workpiece and a copper electrode in kerosene mixed with boron oxide (B2O3) powders, the morphology of the machined specimens at different powder concentrations and pulse duration settings were observed and investigated. In addition, the micro hardness of the layers occurred as a result of EDM was measured and discussed. The highest surface hardness value of 941 HV is measured over machined specimen with B2O3 powder addition, whereas the lowest surface hardness value of 413 HV is measured. [ABSTRACT FROM AUTHOR]

Surface modification is essential to enhance the surface properties of engineering components. This may be accomplished either in the form of altering the surface chemistry or by providing a protective layer over the work surface. In this paper, the surface modification phenomenon by depositing a protective layer over the work surface by electrical discharge machining (EDM) is presented. The potential of EDM, which is otherwise a useful non-conventional machining process, has been explored for surface alteration by depositing material over work surface using tungsten-copper (W-Cu) sintered powder metallurgy tools. The photographic presentation of the EDMed surface at different parameter settings is given. The variations of mass transfer rate (MTR), deposited layer thickness (LT), and average surface roughness ( R) with various parameter combinations are presented in graphical form and their effects are discussed. A wide spectrum of MTR ranging from nearly 1 to 191 mg/min and average surface roughness values ranging from 3 to 15 μm have been achieved. A wide range of deposited layers with thickness varying from 3 to 785 μm has been achieved by various combinations of process parameters. The microstructure of the deposited layers with microhardness at different zones is presented. It has been observed that the microhardness is gradually increasing from the base material to the deposited layer and its maximum value is found to be 15.7 GPa at the hardest zone. SEM, EDX, and XRD analyses has been also performed for further characterization of the deposited layer. A quantitative analysis of the layer has been carried out by EDX and it is found that the inner part of the layer is richer in tungsten than the superficial surface. This contributed towards the higher hardness of the layer at the core. [ABSTRACT FROM AUTHOR]