Fig. 1. Principles of (a) traditional L-PBF and (b) area laser exposure PBF

Fig. 2. 3D powder bed model

Fig. 3. Flat-top light source amplitude distribution characteristics

Fig. 4. Gaussian light source amplitude distribution characteristics

Fig. 5. Forming process of (a) area laser exposure PBF and (b) traditional L-PBF

Fig. 6. Simulated area laser exposure PBF forming process. (a) t=20 μs; (b) t=100 μs; (c) t=200 μs; (d) t=500 μs

Fig. 7. Simulated L-PBF forming process. (a) t=200 μs; (b) t=400 μs; (c) t=1000 μs; (d) t=2000 μs

Fig. 8. Node temperature of the molten pool varies with time. (a) Flat top heat source; (b) Gaussian heat source

Fig. 9. Simulation of temperature field distribution in molten pool cross-section of area laser exposure PBF. (a) t=50 μs; (b) t=100 μs; (c) t=200 μs; (d) t=500 μs

Fig. 10. Simulation of temperature field distribution in YZ section of L-PBF molten pool. (a) t=100 μs; (b) t=200 μs; (c) t=300 μs; (d) t=400 μs

Fig. 11. Simulation of temperature field distribution in XZ section of L-PBF molten pool. (a) t=180 μs; (b) t=200 μs; (c) t=250 μs; (d) t=300 μs

Fig. 12. Surface morphology of molten pool. (a) Y=-200 μm; (b) Y=0 μm; (c) Y=200 μm

Fig. 13. Surface morphology of molten pool formed by PBF forming by area laser exposure in three groups under the same conditions. (a)‒(c) Optical micrograph; (d) molten pool cross-sectional height diagram

Fig. 14. Surface morphology of three groups of L-PBF forming molten pools under the same conditions. (a) (c) (e) Optical micrograph; (b) (d) (f) molten pool cross-sectional height diagram

Fig. 15. Stress state at the solidification interface