Fig. 1. Schematic diagram of experimental equipment and sampling method. (a) Welding process; (b) sampling location diagram of metallographic specimen and tensile specimen; (c) offset welding process diagram; (d) schematic diagram of tensile specimen

Fig. 2. Macroscopic appearances of welds. (a)‒(c) Weld morphologies under low power and low welding speed process parameters; (d)‒(f) weld morphologies under high power and high welding speed process parameters; (g)‒(i) weld morphologies under offset welding process parameters

Fig. 3. Weld microstructures when laser power is 2750 W and scanning speed is 2 m/min. (a)~(n) Macroscopic and metallographic images of welds; (o) EDS scanning result

Fig. 4. Optical microscope (OM) images of weld microstructures when laser power is 5500 W and scanning speed is 5 m/min

Fig. 5. OM images of weld microstructures when laser power is 5500 W, scanning speed is 5 m/min, and GH3128 side offset is 0.2 mm

Fig. 6. SEM images of Ta-10W side reaction layers under three parameter combinations. (a) Laser power is 2750 W, and scanning speed is 2 m/min; (b) laser power is 5500 W, and scanning speed is 5 m/min; (c) laser power is 5500 W, scanning speed is 5 m/min, and GH3128 side offset is 0.2 mm

Fig. 7. Islands in molten pool when laser power is 2750 W and scanning speed is 2 m/min. (a) SEM image of island edge; (b) SEM image of island; (c) SEM image of island interior; (d) EDS line scan result; (e) EDS surface scan result

Fig. 8. XRD test results of base metal and three types of welds

Fig. 9. Microhardness results. (a) Laser power is 2750 W and scanning speed is 2 m/min; (b)laser power is 5500 W and scanning speed is 5 m/min; (c) laser power is 5500 W, scanning speed is 5 m/min, and offset is 0.2 mm

Fig. 10. Tensile strength results. (a) Tensile strength values of base material and weld; (b) stress-strain curve of welded joint

Fig. 11. Fractures of tensile specimens. (a) Laser power is 2750 W and scanning speed is 2 m/min; (b) laser power is 5500 W and scanning speed is 5 m/min; (c) laser power is 5500 W, scanning speed is 5 m/min, and offset is 0.2 mm