On the Optimization of Roughness and Corrosion Resistance of Laser Beam Powder Bed Fusion Fabricated Ti–6Al–4V Parts—An Electrochemical Approach

Abstract

Laser beam powder bed fusion is emerging as a technology for fabricating components made of advanced alloys, such as Ti–6Al–4V. However, it suffers from rough as-built (AB) surfaces, necessitating postprocessing for desired quality and performance. Electrochemical methods such as electrochemical polishing (ECP) and anodization (AN) are promising postprocessing methods; ECP can effectively smoothen surfaces irrespective of their complexity and hardness, while AN enhances the material's corrosion resistance. However, literature lacks research that discusses combined ECP and AN treatment on surface texture evaluation and corrosion behavior. This work presents a detailed study on the effects of different processing factor levels using a Taguchi design of experiment (DOE) approach and discusses the underlying process mechanisms. The optimized treatment conditions to achieve highest roughness improvement and best corrosion resistance are discussed and the most influential postprocessing factors are revealed and ranked. The treatment that achieved smooth surfaces and high corrosion resistance is ECP at 20 V and 15 °C for 20 min, followed by AN at 15 V for 5 min. This treatment achieves a 72% roughness improvement, providing an arithmetic areal surface roughness of 2.63 μm and a corrosion current density of 0.09 μA cm−2, which is almost similar to the AB part.