Fig. 1. Laser remelting test. (a) Laser cladding equipment; (b) molten pool diagram; (c) map of formed single-track

Fig. 2. Microstructures of DD6 nickel-based single crystal superalloy. (a) Morphology of the substrate collected by optical microscopy; (b) phase composition of dendritic collected by electron microscopy

Fig. 3. Molten-pool morphology and microstructures of each crystal region at different laser powers. (a)‒(d) 1200 W; (e)‒(h) 1500 W

Fig. 4. Dendrite morphology and elemental content measurement points in [010] crystal region after laser remelting. (a) 1200 W; (b) 1500 W

Fig. 5. EBSD of the sample after laser melting. (a) Orientation map with the laser power of 1200 W; (b) orientation map with the laser power of 1500 W; (c) {100} pole figure with the laser power of 1200 W; (d) {100} pole figure with the laser power of 1500 W

Fig. 6. Fusion line morphology and stray grain distribution with the laser power of 1500 W. (a) Smooth fusion line; (b) non-smooth fusion line; (c) point-scan elemental analysis spectrum at point C

Fig. 7. EBSD results of molten pool after remelting. (a) Grain boundary angle with the laser power of 1200 W; (b) grain boundary angle with the laser power of 1500 W; (c) misorientation angle distribution with the laser power of 1200 W; (d) misorientation angle distribution with the laser power of 1500 W

Fig. 8. Relationship between the dendrite growth direction and the temperature gradient

Fig. 9. Geometric model boundary conditions and meshing

Fig. 10. Temperature dependence of thermophysical parameters of DD6 alloy. (a) Density; (b) enthalpy; (c) thermal conductivity; (d) specific heat capacity

Fig. 11. Temperature field distributions of molten pool at different laser powers. (a) 1200 W; (b) 1500 W

Fig. 12. Stress field distribution maps in the molten pool at different laser powers. (a) 1200 W; (b) 1500 W

Table 1. Nominal-chemical composition of DD6 nickel-based single crystal superalloy

Table 2. Laser remelting process parameters

Table 3. Chemical composition of interdendritic region and dendritic stem at different laser powers