Effect of printing layer thickness and sintering time on the densification, microstructure and mechanical properties of binder-jetted Ti-6Al-4V alloy

This study examines how printing layer thickness and sintering time jointly affect the densification, microstructure, and tensile behavior of binder-jetted Ti-6Al-4V under a fixed jetting strategy. Specimens were printed with layer thicknesses of 40, 80, and 120 μm and sintered at 1300 °C for 1–5 h. Reducing the layer thickness increased green density and refined the initial pore structure, thereby accelerating pore closure during early sintering. The 40 μm specimens reached the best condition after 2 h, with 94.4% relative density, 4.4% porosity, and an ultimate tensile strength approaches the wrought benchmark. Larger layer thicknesses required longer holding times but showed lower maximum densities within the investigated process window. Prolonged holding also promoted grain growth and possible pore coarsening, which limited further improvement. These results indicate that improving the green-body state by reducing layer thickness is more effective than simply extending sintering time, although ductility and residual defect control remain important for further optimization.