In the present manuscript, authors have made an attempt to find the effect of aluminium powder on the electric discharge machining (EDM) of EN-19 alloy steel. Brass metal is used as electrode material to conduct the experiments. The novelty of paper lies in machining of EN-19 steel using aluminium powder mixed EDM, which is not attempted so far. During experimentation, peak current, pulse on time, gap voltage and concentration of powder are considered as input process parameters for investigating their effect on material removal rate (MRR) and tool wear rate (TWR). Using the surface response modelling, a relationship has been established among the responses and process parameters in EDM. Optimisation of the machining parameters that are responsible for the best combination of MRR and TWR are determined with the help of fuzzy-grey relational analysis. Furthermore, the Micro structural and chemical composition analysis were characterised through Scanning Electron Microscope, Energy Dispersive Spectroscopy and X-Ray Diffraction, respectively. Abbreviations: CCD: Central Composite Design; DF: Degree of Freedom; EDM: Electrical Discharge Machining; EDS: Energy Dispersive Spectroscopy; GRA: Grey Relational Analysis; GRC: Grey Relational Coefficients; GRG: Grey Relational Grade; MRR: Material Removal Rate; MS: Mean of Squares; PMEDM: Powder Mixed Electrical Discharge Machining; RSM: Response Surface methodology; SEM: Scanning Electron Microscope; SR: Surface Roughness; SS: Sum of Squares; TEM: Transmission electron microscopy; TWR: Tool Wear Rate; XRD: X- Ray Diffraction

This study focuses on a comparative analysis of mechanical behavior and microstructural characteristics of Cu matrix (C87600) based hybrid composites reinforced with SiC-Gr_p and WC-Gr_p fabricated by the stir casting process. The graphite particle percentage was kept constant, whereas the content of SiC and WC in the respective composites was varied to analyze the mechanical properties of the fabricated composites. The morphological observation was carried out by field emission scanning electron microscope (FESEM), which revealed uniform dispersion of the reinforced particles in the hybrid composites. Clear phases of SiC and WC along with the Cu alloy were identified by the x-ray diffractometer (XRD). Further, a comparative study was conducted to analyze the mechanical behavior of the Cu-SiC-Gr and Cu-WC-Gr hybrid composites. With the addition of the hard ceramic materials, the tensile behavior and microhardness of both the Cu-based MMCs were improved. The WC-Gr reinforced composites exhibited higher mechanical properties than the SiC-Gr reinforced hybrid composites. Further, the fracture surfaces were also characterized to study the tensile behavior of the fabricated copper-based hybrid composites, which shows that ductile fracture was mainly associated with both hybrid composites.

In the present experimental investigation, titanium carbide (TiC) and red mud are reinforced with aluminium 7075 (Al7075) at 3, 6, 9 and 12 percentages by weight of matrix to produce a flat casting with the help of stir casting process. The mechanical properties such as yield strength, ultimate tensile strength, microhardness, and % elongation are tested and compared. The distribution pattern of the reinforced particles of the samples is studied through a Scanning Electron Microscope (SEM) and X-ray diffraction (XRD) technique. Finally, the micrographs of the fractured surface reveal the features, namely dimples, cracks, voids, ridges and particle fracture that characterise the features of the fractured composite. The ultimate tensile strength of Al/TiC metal matrix composite (MMC) is increased by 48%, whereas a 71% decrease was observed with the addition of red mud. Further, the hardness is increased by 6%, and 62% with TiC and Red mud reinforced AMMCs.