Effects of plasma electrolytic polishing on surface finish and mechanical properties of Ti6Al4V diamond lattices with a specific relative density

Although the significant impact of surface finish on the mechanical properties of metal lattice structures has been confirmed, further quantitative investigations are necessary. In this study, Ti6Al4V diamond lattices with different surface finishes were prepared using Laser Powder Bed Fusion (LPBF) and Plasma Electrolytic Polishing (PEP), and the effects of PEP treatment on surface finish and mechanical properties were investigated. The results showed that the polishing treatment effectively removed adhered powder particles and smoothed the uneven as-processed surface, resulting in a reduction of roughness Ra on the lower surface from an initial 44.0 ± 1.2 μm to 27.9 ± 1.4 μm after the 15-min polishing treatment. Importantly, the impact of the PEP treatment on the mechanical properties varied depending on the strut diameter, potentially attributed to variations in polishing efficiency and defect susceptibility. Finally, the specific mechanical properties were calculated based on the fitted Gibson-Ashby curves, which exhibited a rapid increase during the initial polishing stage and subsequently showed a gradual increase as the adhered powder particles were completely removed and surface roughness decreased gradually.