Behavior and Mechanism of Solid Particle Erosion to Remove Passivation Film on Electrochemically Machined Ta15 Titanium Alloy

Abstract

Titanium alloys are susceptible to form a passivation film during electrochemical machining (ECM). Especially in the secondary ECM, the surface defects such as pitting and dents attributed to the passivation film are particularly obvious. This study investigated the erosion behavior of solid particles on the passivation film of titanium alloys subjected to ECM and the dissolution mechanism of the material during secondary ECM. The findings indicated that particle erosion can effectively remove the passivation film formed on the surface of titanium alloy by ECM. The main erosion behaviors include ploughing, extrusion, compaction, rebound and particle embedding. Moreover, compared to high-angle erosion, the secondary ECM of TA15 titanium alloy following low-angle erosion yielded a completer and more uniform surface. This research provides theoretical insights for the removal of titanium alloy passivation films in ECM processes and for achieving uniform surface quality in secondary ECM.

Keywords: TA15 titanium alloy, Electrochemical machining, Particle erosion, Erosion mechanism, Passivation film