Understanding the Laser Powder Bed Fusion of AlSi10Mg Alloy

Abstract

We examine the microstructural characteristics of LPBF AlSi10Mg produced by using a wide range of LPBF processing parameters with independently varied laser power, hatch spacing, scan speed, slice thickness, and the normalized energy density. The lower energy density produced lack of fusion flaws from residual interparticle spacing, while the higher energy density produced spherical pores from trapped gas. The highest density (> 99%) samples were produced by using an energy density of 32 to 54 J/mm3. Within this energy density range, use of smaller slice thicknesses increased the processing window that would produce dense AlSi10Mg samples. A cellular structure, consisting of Al–Si eutectic and α-Al (fcc) matrix, within melt pools was quantified in size to determine the cooling rate of 105 to 107 K/s. This sub-grain cellular structure was found to decrease in size with increasing scan speed and increasing slice thickness.