Fig. 1. ECY768 alloy powder. (a) Typical morphology; (b) particle-size distribution

Fig. 2. Illustration of grating type laser scanning strategy

Fig. 3. Tensile specimen blank and process test block. (a) Dimensional schematic; (b) photo of forming specimens

Fig. 4. Design dimensions of tensile specimens

Fig. 5. Process window for ECY768 alloy processed by LPBF

Fig. 6. Typical defect characteristics or appearance of representative specimens within different process windows (specimen numbers correspond to those in Fig. 5)

Fig. 7. Comparison of the morphology of pore defects before and after metallographic corrosion. (a) Nearly spherical pores; (b) irregular pores

Fig. 8. EDS and EBSD analysis of cracked regions. (a) EDS; (b) EBSD

Fig. 9. Effect law of process parameters on the porosity. (a) P=200 W, D=0.04 mm; (b) P=300 W, D=0.04 mm; (c) P=400 W, D=0.04 mm; (d) P=200 W, D=0.02 mm; (e) P= 300 W, D=0.02 mm

Fig. 10. Scatter plot of porosity and laser energy density. (a) Laser energy density of 26.04-312.50 J·mm^-3; (b) laser energy density of 62.50-112.50 J·mm^-3

Fig. 11. Scatter plot of crack rate and laser energy density. (a) Laser energy density of 26.04‒312.5 J·mm^-3; (b) laser energy density of 26.04‒65.00 J·mm^-3; (c) laser energy density of 125.00‒312.50 J·mm^-3

Fig. 12. Optical micrographs of ECY768 alloy processed by LPBF after corrosion under the optimized processing parameters. (a) Vertical section; (b) horizontal section

Fig. 13. EBSD-IPF and EBSD-PF of ECY768 alloy processed by LPBF under the optimized processing parameters. (a) Vertical section; (b) horizontal section

Fig. 14. SEM images of microstructure in the grains of ECY768 alloy processed by LPBF under the optimized processing parameters. (a) (c) (e) Vertical sections; (b) (d) (f) horizontal sections

Fig. 15. X-ray diffraction spectra of ECY768 alloy processed by LPBF under the optimized processing parameters

Fig. 16. TEM analysis results of ECY768 alloy processed by LPBF under the optimized processing parameters. (a) HADDF image of sub-grain; (b) EDS maps for Co, Ni, Cr, Ta, Ti, and C elements; (c) HRTEM image of MC type carbide phase and its atomic arrangement along the [0 -1 1] crystal axis of the matrix; (d) HRTEM image of M₂₃C₆ type carbide phase and its atomic arrangement along the [0 -1 1] crystal axis of the matrix; (e) dislocation-carbide interactions

Fig. 17. Microhardness distribution of ECY768 alloy processed by LPBF under the optimized processing parameters

Fig. 18. Tensile engineering stress-strain curves at room temperature for ECY768 alloy processed by LPBF under the optimized processing parameters