Performance determined by microstructure and nano film characteristics during electrochemical transpassive dissolution of laser-directed energy deposited Ti6Al4V alloy

Electrochemical machining (ECM) is well-suited for laser-directed energy deposited (LDED) Ti6Al4V components due to its precise and efficient machining capabilities. This study investigates the electrochemical transpassive dissolution performance of LDED Ti6Al4V specimens with varying α and β microstructural characteristics achieved through the different heat treatments. It is confirmed that increase in the α phase content and elements microsegregation promotes the transpassive film porosity and the electrochemical dissolution rate, subsequently diminishes surface quality. And enhanced current densities of ECM can improve machining efficiency and surface quality. Importantly, high-resolution imaging of the transpassive film reveals its amorphous nanostructure and layered growth morphology. And the impact of microstructure and nano film on dissolution morphology is analyzed and a growth mechanism for the film's stacked-layered structure is proposed.