1：Experimental Design and Method Selection:

Laser polishing experiments were performed using a continuous wave (CW) fiber laser with a maximum laser power of 250 W at a wavelength of 1070 nm. A lens with a 125 mm focal length was used. The sample was protected by Ar gas in a container during the laser-polishing process.

2：Sample Selection and Data Sources:

Rolled Ti6Al4V titanium alloy blocks with the nominal compositions were chosen. The size of the samples was 50 × 50 × 10 mm3 and initial surfaces of the samples were fabricated by end milling.

3：List of Experimental Equipment and Materials:

A continuous wave (CW) fiber laser, optical microscopy (OLYMPUS BX 51 m, Japan), roughness instrument (MITUTOYO SJ-210, Japan), Vickers (HXD-1000TMC, China), scanning electron microscopy (SEM), electron backscattering diffraction (EBSD), X-ray diffraction (XRD) patterns of the polished and unpolished samples were measured by the diffractometer (ADVANCE Da Vinci, Germany).

4：Experimental Procedures and Operational Workflow:

The polishing experiments were performed using a continuous wave (CW) fiber laser. The employed scanning strategy for laser polishing is shown in Fig. 3, and the polishing region measures approximately 6 × 8 mm

5：During laser polishing, there are three key parameters:

laser power, scanning speed, and overlap between the parallel laser tracks.

6：Data Analysis Methods:

Surface topography was observed by optical microscopy, and the surface roughness was measured by a roughness instrument. Micro-hardness at the cross section of the sample was determined by Vickers. The microstructure evolution in laser polished layer was characterized by SEM, and the grain size was evaluated by EBSD. XRD patterns of the polished and unpolished samples were measured by the diffractometer.