Investigation on the effect of solid particle erosion on the dissolution behavior of electrochemically machined TA15 titanium alloy

During electrochemical machining (ECM), the passivation film formed on the surface of titanium alloy can lead to uneven dissolution and pitting. Solid particle erosion can effectively remove this passivation film. In this paper, the electrochemical dissolution behavior of Ti–6.5Al–2Zr–1Mo–1V (TA15) titanium alloy at without particle impact, low (15°) and high (90°) angle particle impact was investigated, and the influence of Al₂O₃ particles on ECM was systematically expounded. It was found that under the condition of no particle erosion, the surface of electrochemically processed titanium alloy had serious pitting corrosion due to the influence of the passivation film, and the surface roughness (S_a) of the local area reached 10.088 μm. Under the condition of a high-impact angle (90°), due to the existence of strain hardening and particle embedding, only the edge of the surface is dissolved, and the central area is almost insoluble, and the surface roughness (S_a) reached 16.086 μm. On the contrary, under the condition of a low-impact angle (15°), the machining efficiency and surface quality of the material were significantly improved due to the ploughing effect and galvanic corrosion, and the surface roughness (S_a) reached 2.823 μm. Based on these findings, the electrochemical dissolution model of TA15 titanium alloy under different particle erosion conditions was established.