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This study presents a comprehensive comparison of stripe and chessboard scanning strategies in laser powder bed fusion (L-PBF) of Ti-6Al-4V, focusing on their effects on microstructure, mechanical performance, residual stress evolution, porosity, corrosion resistance in simulated body fluid (SBF), and in vitro biocompatibility. All samples were fabricated under identical volumetric energy density (VED = 50 J/mm³) using constant laser parameters (180 W, 1000 mm/s, 120 µm hatch spacing, 30 µm layer thickness). Microstructural characterization revealed distinct α′-martensite morphologies and melting-pool geometries for the two strategies. Residual stresses measured by the XRD sin²ψ method showed that the chessboard strategy produces higher compressive surface stresses (∼ −660 MPa), whereas the stripe strategy results in lower-magnitude tensile stresses (∼ +450 MPa). Thus, while chessboard does not reduce the overall stress magnitude, it alters the stress state by promoting more localized thermal equilibration within each island. In contrast, the stripe strategy generates smoother thermal gradients along extended scan tracks, leading to a lower net stress magnitude. Mechanical testing demonstrated higher strength for the chessboard-processed sample (∼1025 MPa), whereas the stripe strategy achieved greater ductility. Electrochemical measurements revealed superior corrosion resistance for stripe-processed samples, with heat treatment decreasing corrosion resistance for both strategies due to passive-film destabilization. In vitro assays (MTT and cell adhesion) confirmed enhanced biocompatibility for the stripe strategy and significantly reduced cell viability for the chessboard strategy. Overall, the findings clarify how scan-path design governs residual stress mode, microstructure development, and coupled mechanical/biological responses in L-PBF Ti-6Al-4V, providing practical guidance for optimizing implant manufacturing parameters.
Sherafati et al. (Fri,) studied this question.