The Anisotropic Electrochemical Machinability of Laser Cladding Deposited Ti6Al4V Alloy in NaCl Solution

The hybrid manufacturing method of laser cladding deposition (LCD) additive manufacturing and electrochemical machining (ECM) is a promising approach to advanced manufacturing technology for difficult machined materials. The anisotropic electrochemical performance of LCD-produced Ti6Al4V alloy was studied in 15 wt.% NaCl solution by polarization curve measurements and ECM tests. The horizontal-plane (X0Y plane) exhibits a more stable passive film in both static electrolyte and low current density ECM processes than the vertical-plane (X0Z plane). Additionally, the horizontal-plane exhibits a higher material removal rate and more consistent dissolved surface roughness in comparison with the vertical-plane during the high current density ECM process. The microstructure of the LCD-produced Ti6Al4V alloy on the horizontal-plane consisted of equiaxed-like prior-beta grains and slightly finer alpha-laths but was composed by columnar prior-beta grains and coarser alpha-laths on the vertical-plane. These differences in the microstructural characteristics produce the distinctions observed in the electrochemical dissolution behavior and electrochemical machinability on the horizontal- and vertical-planes.