Fig. 1. Morphology and particle size distribution of gas atomized 15-5PH powder. (a) Powder morphology; (b) particle size distribution; (c) scanning electron microscope image of powder; (d) microstructure of powder

Fig. 2. Schematic diagram of 15-5PH sample prepared by L-DED and sampling positions. (a) Schematic diagram of samples and sampling positions in different forming directions; (b) schematic diagram of scanning strategy; (c) dimensions of tensile test specimens

Fig. 3. XRD patterns of different regions in 15-5PH samples prepared by L-DED

Fig. 4. Optical micrographs of 15-5PH stainless steel prepared by L-DED in different forming directions. (a) Optical micrograph in xy direction; (b) optical micrograph in z direction

Fig. 5. Microstructure of 15-5PH stainless steel prepared by L-DED in parallel to scanning direction. (a) Macroscopic morphology of microstructure in xy direction; (b) microstructure of top region; (c) microstructure of middle region; (d) microstructure of bottom region

Fig. 6. Different regions with orientation imaging maps parallel to scanning direction. (a) Top region; (b) middle region; (c) bottom region

Fig. 7. Distribution of grain sizes in different regions parallel to scanning direction. (a) Top region; (b) middle region; (c) bottom region

Fig. 8. Microstructural evolution of 15-5PH samples prepared by L-DED along deposition direction. (a)‒(c) Microstructure of top region; (d)‒(f) microstructure of middle region; (g)‒(i) microstructure of bottom region

Fig. 9. Orientation map along deposition direction of 15-5PH stainless steel and temperature distribution curves at different positions. (a) Sample orientation imaging map in z direction; (b) schematic diagram of feature point locations; (c) numerical simulation of temperature distribution curves at different positions for 15-5PH stainless steel

Fig. 10. Distribution of grain sizes along deposition direction

Fig. 11. Vickers hardness values and indentation morphology along deposition direction. (a) Vickers hardness values and indentation morphology in z direction; (b) microscopic image of hardness indentation morphology in horizontal direction at S₃; (c) Vickers hardness values in the horizontal direction at S₃; (d) Vickers hardness values in z direction after heat treatment

Fig. 12. Room temperature tensile properties of 15-5PH samples prepared by L-DED in different directions. (a) Tensile curves; (b) tensile performance bar chart

Fig. 13. Fracture morphologies of 15-5PH samples prepared by L-DED in different forming directions. (a)‒(c) SEM images of fracture surfaces in xy direction; (d)‒(f) SEM images of fracture surfaces in z direction