Fig. 1. SEM images of AlSi10Mg alloy powder. (a) 400×; (b) 2000×

Fig. 2. Circular channel samples of different diameters. (a) Three-dimensional model of specimens; (b) circular channel formed by LPBF

Fig. 3. Ridge shape channel samples with different section sizes.(a) Three-dimensional model of specimens; (b) schematic of section size dimensions when B=6 mm; (c) ridge shape channel formed by LPBF

Fig. 4. Schematic of test size of channel sample. (a) Circular channel; (b) ridge shape channel

Fig. 5. Three-dimensional model of complex channel cooling element.(a) Front view of model; (b) bottom view of model; (c) position of ridge shape channel; (d) partial section view of side channel

Fig. 6. Schematic of inclination angle. (a) Circular channel; (b) ridge shape channel

Fig. 7. Schematic of mechanism of powder particles adhering to inner surface of channel. (a) Circular channel; (b) ridge shape channel

Fig. 8. Circular channel samples formed by LPBF with different diameters. (a) Front view and (b) top view of specimens; (c) circular channel sample formed by LPBF with axial section of channel; (d) circular channel sample formed by LPBF; (e) Φ2 mm, (f) Φ2.5 mm, (g) Φ3 mm, (h) Φ4 mm, (i) Φ5 mm, and (j) Φ6 mm of inner surface of channel

Fig. 9. Ridge shape channel samples formed by LPBF with different section sizes. (a) Front view and (b) top view of specimens; (c) ridge shape channel samples formed by LPBF with axial section of channel; (d) ridge shape channel samples formed by LPBF; (e) B=2 mm, (f) B=2.5 mm, (g) B=3 mm, (h) B=4 mm, (i) B=5 mm, and (j) B=6 mm of inner surface of channel

Fig. 10. Powder cleaning scheme for complex channel cooling element formed by LPBF at the turning part of flow channel. (a) Process hole for powder discharge with a diameter of 2 mm; (b) process hole is blocked by set screw and thread glue

Fig. 11. Complex channel cooling element formed by LPBF.(a)LPBF forming process of channel 1;(b)LPBF forming process of channel 2; (c) top view; (d) bottom image; (e) side view; (f) partial section view

Fig. 12. X-ray test of complex channel cooling element. (a) Location diagram; detection images of (b) 1# area, (c) 2# area, (d) 3# area, (e) 4# area, and (f) 5# area

Fig. 13. CT test of channel cooling element formed by LPBF

Fig. 14. Pressure test of complex channel cooling element. (a) Filling channels with water; (b) pressure gauge; (c) process of pressure test