Fig. 2: Pore formation mechanisms during DED.

a Pore formation dynamics. Ai, a pore was captured to form in the melt pool from the porosity in the powder feedstock particle at a substrate traverse speed of 1 mm s⁻¹, a laser power of 160 W, layer 3; Aii, a pore formed from a powder when the laser melts the powders at a substrate traverse speed of 1 mm s⁻¹, a laser power of 160 W, layer 1. b Bi, a pore formed from the porosity in the previous layers. c Schematic illustration of the pore formation mechanism at a traverse speed of 1 mm s⁻¹, a laser power of 160 W, layer 3. d Accumulative number of pores from powders and previous layers with increasing time in DED at a traverse speed of 1 mm s⁻¹, a laser power of 160 W, layer 3. e Pore formation rate from porosity in powders and previous layers in DED at a traverse speed of 1 mm s⁻¹, a laser power of 160 W, layer 3; a traverse speed of 2 mm s⁻¹, a laser power of 160 W, layer 3, respectively. Error bars represent standard deviation. See the videos corresponding to (a–c) in Supplementary Movies 2 and 3. Scale bars in (a, b) are 300 μm.