Evaluations of surface morphology in EDMed MoSi2-SiC intermetallic ceramic composite surfaces

Abstract

Machining a 5 mm hole in molybdenum disilicide-silicon carbide, an extremely rigid and robust intermetallic compound, is challenging. The effectiveness of Electrical Discharge Machining (EDM) was evaluated using standard metrics such wear ratio, material removal rate, electrode wear rate, average surface roughness, and geometrical tolerances. This research article notably features an in-depth analysis of the melting and evaporation mechanism of metal removal, along with the topography of the machined surface, using an EDS and XRD report, machined electrodes, and WEDM machined brass wire. Surface morphologies have been characterized using scanning electron microscopy (SEM) at the several experimental levels for the machined composite, electrode, and wire. Current of 5 A, pulse on time of 8 µs, pulse off time of 6 µs, spark gap of 0.16 mm, dielectric pressure of 20.5 kg/cm2, metal removal rate of 0.00117 g/min, electrode wear rate of 0.00011 g/min, wear ratio of 10.60%, and surface roughness of 0.441 µm achieved the best results. According to the evaluation and analysis of porosity values, the level 1 trial’s hole has a porosity value of 0.966%, the level 3 trial’s t hole has a porosity value of 5.655%, and the level 2 trial’s hole has a porosity value of 1.424%. The experimental results on the machined surface of the copper electrode show that by selecting the best level of process parameter combination, the machining accuracy with good geometrical tolerances, surface quality are enhanced and number of micro voids, and size of cracks were all minimized.