The change of surface alloy compositions and corrosion behavior after WEDM machining of commercially pure titanium (grade 4) and Ti-6Al-4V (grade 5)
Keywords:Corrosion, Diffusion, WEDM, Titanium, Ti-6Al-4V
Nowadays, titanium and its alloys are widely used in medical applications because of excellent corrosion resistance and a high strength-to-weight ratio. Nevertheless, titanium and its alloys are classified as difficult-to-machine metals by conventional machining methods. Therefore, unconventional machining processes are recommended. Wire-electrical discharge machining (WEDM) has become an important non-traditional machining process, as it provides an effective solution for machining components made from difficult-to-machine metals. However, WEDM could damage the surface layer and have an effect on the biocompatibility properties. This research was focused on the effect of WEDM on grade 4 commercially pure titanium and Ti-6Al-4V (Grade 5) after WEDM cutting. The diffusion of wire substance was studied, and corrosion behavior in Hank’s solution was examined. The experimental result showed that the depth of damaged layer on WEDMed specimens was around 5-12 μm, and the surface compositional analysis showed a very limited depth of contamination from wire electrode. The corrosion rate of the WEDMed specimens are 300 - 400 higher than the rate found in the as-received specimens.
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