Influence of preprocessing methods on the electrochemical machining of TA15 alloy: Experimental phenomena and mechanism analysis

Electrochemical machining (ECM) is an effective method for processing difficult-to-machine materials, such as titanium alloys. Achieving high-quality surfaces on titanium alloys through ECM has been a prominent research focus. This study comprehensively analyzes the impact of various preprocessing methods on the ECM of TA15 alloy and investigates the mechanisms behind the observed differences. The experimental results demonstrate that preprocessing methods significantly affect both surface quality and material removal rate, particularly during the secondary ECM process. Specifically, initial counter-rotating electrochemical machining (CRECM) on machined or polished surfaces can achieve satisfactory surface quality (about Ra 2 μm). However, in secondary CRECM on ECM surface, surface quality markedly deteriorates, with surface roughness ranging from Ra 7.06 μm to Ra 36.81 μm. In contrast, sandblasting preprocessing yields a surface roughness of less than Ra 2.4 μm during secondary CRECM, meeting the surface quality requirements for aerospace engine casings. Finally, material dissolution mechanisms of different preprocessed surfaces are established.