Fig. 1. Microstructure and particle size distribution of TC4 powder. (a) Powder morphology; (b) percentage of powder particle size

Fig. 2. Forming process of SLM sample

Fig. 3. Geometric dimension of tensile sample

Fig. 4. Typical surface morphologies and measured roughness values of TC4 samples with different laser remelting times. (a) Upper surface not remelted; (b) side surface not remelted; (c) upper surface remelting once; (d) side surface remelting once;(e) upper surface remelting twice; (f) side surface remelting twice

Fig. 5. Schematic diagram of sampling observation

Fig. 6. Section defects of TC4 samples with different remelting times. (a1)(a2) Not remelted; (b1)(b2) remelting once; (c1)(c2) remelting twice

Fig. 7. Tensile strength and elongation of TC4 samples with different remelting times. (a) Relationship between remelting times and elongation; (b) relationship between remelting times and tensile strength

Fig. 8. Fracture morphology of tensile samples with different remelting times. (a1)(a2) Not remelted; (b1)(b2) remelting once; (c1)(c2) remelting twice

Fig. 9. Microstructure of TC4 formed by SLM with different laser remelting times. (a) Not remelted; (b) remelting once; (c) remelting twice

Table 1. Mass fraction of each component of TC4 titanium alloy powder