Study of Microstructure and Surface Morphology of AlSi10Mg Alloy Manufactured by Laser Powder Bed Fusion

This study divides the laser scanning region into contour and infill regions. AlSi10Mg alloy specimens were fabricated by laser powder bed fusion (LPBF) using different parameters to explore parameter combinations that yield high relative density and excellent surface quality. The results indicate that when the parameters in the contour region are P = 353.2w, V = 626.3 mm/s, D = 0.02 mm, and in the infilling region are P = 400.0w, V = 1352.0 mm/s, H = 200.0um, specimens with high relative density and good surface quality can be obtained. The relative density of these samples is 0.9991, and the surface roughness of the planes parallel to the build direction (XOZ/YOZ plane) is 5.895 µm. When the scanning speed and laser power in the contour region are high, metal vaporization and recoil pressure destabilize the melt pool, resulting in large protrusions, depressions on the surface, and increased surface roughness. At higher energy densities, metal vaporization and recoil pressure cause the melt pool surface to penetrate the material, forming vapor cavities and generating numerous keyholes. Specimens for tensile and compression testing were prepared using the above process parameters: the mean tensile strength of the XOZ/YOZ plane is 392.55 MPa, the mean tensile strength of the XOY plane is 328.2 MPa, and the mean compressive strength is 702.2 MPa.