Fig. 1. Aerosolized IN718 alloy powder. (a) Morphology captured by microscopy; (b) particle size distribution

Fig. 2. Heat treatment processes used in selective laser melted IN718 alloy

Fig. 3. Fatigue sample. (a) Dimension of fatigue specimen; (b) photo of selective laser melted IN718 fatigue specimen

Fig. 4. Strain changes with loading time at the beginning of low cycle fatigue of IN718 alloy

Fig. 5. Microstructures of heat-treated IN718 alloy captured by microscopy. (a) SA specimen; (b) HA specimen; (c) HSA specimen; (d) electron microscopy observation diagram

Fig. 6. Fatigue testing results of IN718 alloy with different heat treatment processes

Fig. 7. Fracture images of heat-treated specimens after fatigue test. (a) SA specimen; (b) HA specimen; (c) HSA specimen; (d) fatigue source area; (e) fatigue expansion area; (f) transient fracture area

Fig. 8. EBSD analysis of specimens after different heat treatments. (a)(d)(g) Grain orientation diagrams; (b)(e)(h) contrast and grain boundary composite diagrams; (c)(f)(i) KAM diagrams

Fig. 9. Strengthening mechanism and profile images of specimens after heat treatments. (a) Strengthening mechanism of fatigue performance; (b) profile image of SA specimen; (c) profile image of HA specimen; (d) profile image of HSA specimen; (e) fracture of HSA specimen