Fig. 1. Experimental setup for laser powder feeding welding

Fig. 2. Relationship between powder feeding rate and analog quantity

Fig. 3. Schematic diagram of the test method of cross-sectional topography

Fig. 4. Typical weld surface and section morphology. (a) P=1.2 kW, v=20 mm/s, M=8.27 g/min, D=0.05 mm; (b) P=1.2 kW, v=16 mm/s, M=12.69 g/min, D=0.05 mm

Fig. 5. Influence of butt gap on weld morphology. (a) Weld width; (b) bump/collapse depth of upper surface

Fig. 6. Evolution of molten pool with different butt gaps. (a) 0.05 mm; (b) 0.25 mm; (c) 0.30 mm

Fig. 7. Influence of powder feeding rate on weld morphology. (a) Weld width; (b) bump/collapse depth of upper surface

Fig. 8. Evolution of molten pool flow with different powder feeding rates. (a) Little powder; (b) bulk powder

Fig. 9. Evolution of molten pool flow with different welding speeds. (a) Weld width; (b) bump/collapse depth of upper surface

Fig. 10. Influence of process parameters on weld morphology

Fig. 11. Effect of process parameters on tensile strength. (a) Butt gap; (b) welding speed; (c) powder feeding rate

Fig. 12. Microstructure of weld with different powder feeding rates. (a) 0.75 g/min; (b) 5.06 g/min; (c) 8.27 g/min