Selective laser melting of aluminum-alumina powder composites obtained by hydrothermal oxidation method

Selective laser melting of Al-Al(2)O(3)core-shell composite with 10 wt.% of alumina was studied. The initial powder was obtained by hydrothermal oxidation of aluminum powder. A matrix of parameters was selected for selective laser melting of composites, including laser power from 180 to 220 W, scanning speed from 180 to 220 mm/s, and hatch spacing from 0.13 to 0.18 mm. The type of microstructure, relative density, and hardness of synthesized objects were determined. The influence of the laser's areal energy density on the properties of synthesized objects was studied. Depending on the ED(a)used, different types of microstructure were formed. The ED(a)within the range 7-8 J/mm(2)was found to be optimal for SLM of Al-10 wt.% Al(2)O(3)core-shell powder composites. Beyond this range, uncomplete powder melting as well as boiling of the aluminum leads to the low density and formation of microcracks after solidification. The hardness of the finest synthesized sample (58.3 +/- 0.9 HB) and uniform distribution of alumina was obtained at EDa = 7.69 J/mm(2)with the following SLM parameters:P = 220 W;h = 0.13;V = 220 mm/s. Based on the obtained results, further research using SLM with double exposure of the layer with a laser beam was suggested.