Impact of Surface Post-Treatments on the Properties of Additively Manufactured Ti-6242 Alloy

Impact of Surface Post-Treatments on the Properties of Additively Manufactured Ti-6242 Alloy Abstract Metal additive manufacturing is an advancing technology enabling the creation of complex parts; however, these parts often exhibit poor surface quality and defects that can negatively impact performance, particularly fatigue and wear resistance. This study investigates the effects of various surface post-treatments—grinding, laser polishing, tumble finishing, and chemical polishing—on Ti-6Al-2Sn-4Zr-2Mo (Ti-6242) parts produced via laser powder bed fusion (L-PBF). Initial work focused on optimizing L-PBF parameters to produce dense, low-defect samples fabricated using a Print Sharp 250 L-PBF machine. Samples were evaluated for density using the Archimedes method and X-ray computed tomography, while surface roughness and quality were assessed. Surface treatment techniques included manual grinding with silicon carbide papers, wet tumbling for 3 hours with ceramic abrasives, chemical polishing in a controlled solution, and laser remelting with varying parameters. The average surface roughness (Ra) was measured to evaluate the effectiveness of each treatment. Additionally, microhardness testing and microstructural evaluation—including optical microscopy and scanning electron microscopy (SEM)—were conducted on both treated and as-built surfaces to examine changes in surface integrity and subsurface features. Future phases will involve nanoindentation to assess hardness variations beneath the surface and X-ray diffraction (XRD) for residual stress analysis. These outcomes will provide comprehensive insights into the microstructural and mechanical effects of each technique, guiding the development of optimized surface finishing strategies for specific applications on demand.