Microstructure Characterisation of Electrical Discharge Craters using FIB/SEM Dual Beam Techniques

Abstract

This paper presents the characterisation of erosion craters caused by high voltage ignition discharges on the surface of electrodes. By means of FIB/SEM dual beam techniques such as FIB‐cross sectioning, FIB‐nanotomography and FIB‐EBSD, the microstructure modification below the crater surface is investigated, providing new insights into erosion crater phenomena. It demonstrates also that the use of FIB/SEM is ideally suited for assessing the microstructural nature of sub‐micron surface degradation features.

Experimental Analysis and Optimization of EDM Parameters on HcHcr Steel in Context with Different Electrodes and Dielectric Fluids Using Hybrid Taguchi-Based PCA-Utility and CRITIC-Utility Approaches

“…Oxygen gas produced better MRR compared to liquid dielectrics [30]. Although oxygen gas performances are better, liquid dielectrics are preferred to obtain stable discharging [31]. Surface modification of titanium alloy was carried out by applying two methods such as electric discharge coating and EDM processes subjected to Nb powder mixed in dielectric fluid medium [32].…”

FEM Simulation of the temperature distribution and power density at platinum cathode craters caused by high voltage ignition discharges

“…The molten pool shape of the crater can be seen as a portion of a sphere cut off by a plane [35]. Thus, the molten volume V m can be accurately estimated using the spherical cap volume formula:…”

“…The grey band in figure 6 symbolizes the experimental data of molten depths (∼1 µm) and molten volumes (200-250 µm 3 ). These data were obtained by performing focused ion beam (FIB) cross sections across high voltage ignition craters and by measuring the extent of the observed molten zones [35]. The corresponding surface spot temperature differs strongly depending on the pulse duration.…”