Fig. 1. Summary of defect types during selective laser melting process (the inset figures are collected from references[4，17，28])

Fig. 2. Effects of several energy density indicators on relative density of selective laser melted materials (experimental data in the figures are collected from references [45，48-57] and the thermo-physical parameters used to calculate energy density indicators are collected from references [58-60])

Fig. 3. Effects of several dimensionless numbers on relative density of selective laser melted materials (experimental data in the figures are collected from references [45，48-51，56-58] and the thermo-physical parameters used to calculate the dimensionless numbers are collected from references [58-60])

Fig. 4. Microstructures of selective laser melted 316L sample^[19], where nano-inclusions are indicated by the blue arrows. (a) Melt pool; (b) cell structure; (c) nano-inclusions

Fig. 5. Melt pool shape at various energy densities. (a)(b) Melt pool morphologies at different area energy densities^[25]；(c)(d) melt pool morphologies at volume energy density of 81 J/mm³ and 150 J/mm³, respectively^[73]

Fig. 6. Single tracks morphologies at different volume energy densities^[74]. (a) Top views; (b) cross-sectional views

Fig. 7. Melt pool morphologies at various process parameters(dark blue arrows indicate keyhole defects, while the green ones represent irregular defects)^[26]

Fig. 8. Texture control by modulation of melt pool morphologies. (a)-(f) Melt pools and textures under different laser beams and laser powers^[14]; (g)-(k) melt pools and textures observed in the specimens fabricated with low and high energy densities^[82]

Fig. 9. Effect of process parameters on cellular structure and tensile property of an selective laser melted 316L stainless steel^[26].(a) Effect of process parameters on cellular structure size; (b) engineering stress-strain curves at low energy density

Fig. 10. Typical morphology of indent with the load of 0.98 N and of 9.8 N, respectively^[28]

Fig. 11. A summary of academic viewpoints on high strength and high ductility mechanisms of selective laser melted 316L stainless steel^{[14,19,21,24,88]}

Fig. 12. Microstructures of 316L fabricated by selective laser melting. As-built part: (a) melt pool morphology; (b) cellular structure. As-fractured samples: (c) melt pool morphology; (d) optical microscopy (OM) image showing the debonding of melt pool; (e) a high magnified scanning electron microscopy (SEM) image showing the seriously elongated cellular structure after tensile test; (f) SEM image showing the fractured location occurs at both cellularstructure and cellular dendrite structure

Fig. 13. Grain maps of selective laser melted 316L stainless steel at different strain levels. (a) As-built; (b) 15%；(c) 30%; (d) 46%

Fig. 14. Melt pool, crystalline grain, and cellular structure of selective laser melted 316L stainless steel evolution as a function of annealing temperature^[83]

Fig. 15. Variation of yield strength of selective laser melted 316L with annealing temperature^[83], and the data in the figure are from the literatures[18，84-85，87，90，92，117，123，133], where the blue dashed lines indicate the general variation trend

Fig. 16. Applications of selective laser melted 316L stainless steel^[135-140]