Surface Characterization of Magnesium Alloy Machined by Wire Electrical Discharge Machining

Abstract

AZ31 magnesium alloy has been widely used in the aerospace and automobile industry due to its weight‐to‐strength ratio and good corrosion resistance properties. However, due to its low melting point and high reactivity, machining this alloy is difficult. Wire Electrical Discharge Machining (WEDM) is a noncontacting machining process that can effectively remove material by electrical discharges. This research work has attempted to investigate the material removal rate of the AZ31 magnesium alloy with various combinations of pulse on‐time ( T on ), pulse off‐time ( T off ), and servo voltage (SV). Two different parameter sets were evaluated with the use of the FANUC Series WEDM machine. Brass wire electrode of 0.25 mm and deionized water were used as the dielectric fluid. Surface roughness of the samples was determined with the help of Mitutoyo SJ‐310 surface roughness tester and SEM was used to analyze the machined surfaces. For the first parameter set ( T on  = 16 µs, T off  = 118 µs, SV = 40 V), the average surface roughness was 5.15 µm and the machining time was 201 s. On the other hand, the average surface roughness of the second parameter set ( T on  = 10 µs, T off  = 12 µs, SV = 15 V) was 4.45 µm. The differences in voids and microcracks properties between the two sets of parameters were also noted. From these findings, it can be seen that there are differences in terms of the surface finish, machining time and the surface morphology when using these two sets of parameters. However, the effect of each of the T on , T off , and SV parameters cannot be distinguished since these three parameters were changed simultaneously. Future studies may involve a well‐designed experiment called the DoE approach, for example, Taguchi methodology.