Fig. 1. Schematic of 3D-GH3536/R-GH3128 butt welding experimental setup

Fig. 2. Schematic of base metal tensile specimen size

Fig. 3. Schematic of weld tensile specimen size

Fig. 4. Cross-section morphologies of welds under different powers. (a) 3000 W; (b) 3500 W; (c) 3800 W; (d) 4300 W

Fig. 5. Cross-section morphologies of welds under different defocusing amounts. (a)－5 mm; (b) 0 mm; (c) +5 mm

Fig. 6. Microstructures of 3D-GH3536. (a) Perpendicular to forming direction; (b) parallel to forming direction

Fig. 7. Macroscopic appearance of 3D-GH3536/R-GH3128 weld

Fig. 8. Microstructures of laser welded joint. (a) Microstructure of joint; (b) microstructure at centerline; (c) microstructure at fusion line of R-GH3128 base metal; (d) microstructure at fusion line of 3D-GH3536 base metal

Fig. 9. EBSD images of weld. (a) Microstructure of joint; (b) EBSD image at fusion line on R-GH3128 side; (c) EBSD image at center line; (d) EBSD image at fusion line on 3D-GH3536 side

Fig. 10. EBSD analysis results of weld center area.(a) Grain diagram in center of weld; (b) grain size distribution diagram; (c) grain boundary dislocation angle distribution diagram

Fig. 11. EDS line scanning results of Fe element. (a) Upper part of joint; (b) middle part of joint; (c) lower part of joint

Fig. 12. Microhardness distribution of welded joint

Fig. 13. Tensile strength of welded joints

Fig. 14. Macroscopic morphologies of fracture. (a) GH3128 base metal; (b) 3D-GH3536 base metal; (c) upper weld; (d) lower weld

Fig. 15. Fracture morphologies of welded joint. (a) Fracture morphology of upper part of welded joint; (b) fracture morphology of lower part of welded joint