Experimental investigation on microwave sintered composite tool for electro-discharge machining of Titanium alloy

The present study was aimed at investigating the machinability characteristics of titanium alloy (Ti6Al4V) by electro-discharge machining (EDM) process. The machining was performed using composite tools made of Cu-W-B4C having different compositions manufactured with the help of hybrid microwave sintering (MWS) process. For this experimental investigation, machining performances in terms of material removal rate, tool wear rate and surface characteristics of the machined surfaces were measured as outcomes. The surface characteristics like surface cracks and white layer formation were evaluated with the help of micrographs of the machined surfaces using scanning electron microscope (SEM). Phase identification of the machined surface was carried out with the help of X-ray diffraction (XRD) analysis to identify the effect of sintered tools on the machined surface. The energy dispersive X-ray spectroscopy (EDS) result of the machined surfaces revealed transfer of tool materials (copper and tungsten) onto the machined surface. The removed tool materials deposited on the machined surfaces forms white layer which was found responsible for increasing the micro-hardness of the machined surface. The EDS results of the machined zone were seen in good agreement with the phases identified with XRD analysis with formation of metal carbides such as titanium carbide and vanadium carbide. The study will serve as a testbed in developing a strong link between the MWS composite tool and machining behaviour during EDM of titanium alloys.