Reflectance Characteristics of Al Alloys Containing Si, Mg, Cu, and Lanthanide (Nd, Sm, Gd) for 3D Printing

To fabricate a low-reflectance aluminum alloy, we have analyzed the changes in reflectance according to the morphology, components, and composition of the aluminum alloy. We find that the larger the particle size of the powder, the lower is the reflectance. This is attributed to the fact that the larger the particle size, the greater is the amount of light absorbed into the interparticle space in the powder. In addition, the reflectance decreases with increase in the Si and Mg contents, because of the lower reflectance of the strengthening phase formed in the alloy as compared to that of aluminum. In contrast, lanthanide addition causes an increase in the reflectance, which is attributed to an increase in the electrical conductivity of the alloy.