Porosity of Additive Manufacturing Products Obtained by Selective Electron Beam Melting

The porosity of the material of samples manufactured by selective electron beam melting from Ti–6Al–4V alloy powders was studied. The influence of parameters of the hatching mode on the porosity of the samples was investigated by optical microscopy and X-ray computed tomography. The shapes and sizes of pores were qualitatively and quantitatively assessed, and the technological factors contributing to the formation of pores were refined. It was shown that large discontinuities are formed mainly in the overlapping area of the contouring and hatching zones at a distance of up to 2 mm from the sample surface. Selective formation of pores in the surface layer was not detected. It was found that, in the range of linear energy densities of the electron beam of 180–300 J/m, the minimum porosity is achieved within this range.