1：Experimental Design and Method Selection

The study used the same laser parameters and scan strategy for all specimens to ensure a sample density higher than 99.5%. Two different surface topographies were obtained by using the top and side surfaces of the specimens.

2：Sample Selection and Data Sources

Ti6Al4V alloy feedstock powder with a spherical morphology and specific particle size distribution was used. Specimens were produced on the same construction plate with a ProX? DMP 200 SLM equipment.

3：List of Experimental Equipment and Materials

ProX? DMP 200 SLM equipment, Instron 8801 for four-point bending fatigue tests, SEM LEO 1350 FEG for fracture surface analysis, Infinitefocus G5 focus variation microscope for surface topography measurement.

4：Experimental Procedures and Operational Workflow

Specimens were detached from the plate by wire EDM after heat treatment. Four-point bending fatigue tests were performed with a maximum stress of 870 MPa and R=-1 until failure. Surface topographies were measured with a focus variation microscope.

5：Data Analysis Methods

Fracture surface features were analyzed by SEM and focus variation microscopy. Surface roughness parameters Sa and Svk were plotted versus the number of cycles to failure N.