Fig. 1. (a) Influence of the linear energy input (EL=P/υ) on the width of single track. The track morphologies can be classified as (b) narrow and discontinuous (P = 200 W, υ = 400 mm/s), (c) narrow and continuous (P = 250 W, υ = 400 mm/s) and (d) wide and smooth (P = 300 W, υ = 400 mm/s), as marked in Fig. 1(a) (Ⅰ, Ⅱ and Ⅲ, respectively). (e) SEM image shows the thin-walled tungsten part fabricated by LPBF. (f) Design of tungsten part by integrating thin-wall into block.

Fig. 2. (a) Schematic illustration for the ITWB scanning strategy. The corresponding microstructure evolutions for tungsten are displayed in 2(b-d), respectively. (e) A schematic diagram of the zigzag scan strategy. (f) The corresponding microstructure. Note: BD is building direction.

Fig. 3. OM images for the polished specimens on the horizontal cross section (x-y): (a) Wb, (b) Ws; and on the vertical section (x-z): (c) Wb, (d) Ws; IPF images for Wb (e) and Ws (f); KAM images for Wb (g) and Ws (h). Color keys for the IPF maps are inserted in 3e and 3f for the color presentation.

Fig. 4. (a) Electrical resistivity and electrical conductivity of Wb and Ws, as a function of temperatures; thermal conductivity, contributions from electron and phonon to the total thermal conductivity for (b) Wb and (c) Ws. It should be noted that the thermal conductivity values denoted with hollow circles were calculated by fitting the measured values.