Optimization of ethanol/ethylene glycol ratio and current density for electrochemical polishing of Ti6Al4V alloy with recast layer

Wire electrical discharge machining (WEDM) of the Ti6A14V alloy surface generates a recast layer and microcracks, which seriously affects the strength and corrosion resistance of the parts. Electrochemical polishing is widely used in metal surface finishing due to its low cost and high efficiency. To solve the problem of surface quality after WEDM machining, in this paper, electrochemical polishing of Ti6Al4V alloy after machining is investigated for different ethanol/glycol ratios of polishing solution and surface corrosion resistance. Based on this study, the effect of current density on the surface roughness, morphology, and corrosion resistance of WEDM-machined parts was also analyzed. By optimizing the ethanol/glycol ratio and current density, a micron-sized impurity-free Ti6Al4V surface was obtained at a glycol/ethanol ratio of 4:1 and a current density of 0.55 A cm⁻², and the surface roughness (Ra) was reduced from 3.69 to 0.40 μm. The microcracks and recast layer were completely removed, the corrosion current density was reduced by one order of magnitude, and the corrosion resistance was significantly improved, which amounted to 0.49 ± 0.04 µA cm⁻².