Effects of EDM on the Chemical Composition and Microstructure of the Surface Layer of Alnico Alloys

This article deals with the effects of electrical discharge machining (EDM) on the chemical composition and microstructure of cast Alnico alloys, i.e., iron-based alloys composed of aluminum, nickel and cobalt. The experiments focused on determining the chemical composition of the surface layer before and after the EDM process. The microstructure of the material altered by the EDM was also examined. The study included measurement of the thickness of the white layer characteristic of EDM. It is evident that low values of the surface roughness parameters can be obtained by correctly selecting the EDM process parameters. The average surface roughness reported in the experiments was 1 mu m. The surface roughness measurements were conducted with a Talysurf CCI lite non-contact profiler. The metrological results also indicate that lower surface roughness can be obtained at small discharge energies.