Fig. 1. Surface morphology of 12CrNi2 alloy steel powder

Fig. 2. Heat treatment procedure for the LAM 12CrNi2 alloy steel

Fig. 3. Schematic of tensile sample

Fig. 4. Microstructure of the as-deposited LAM 12CrNi2 alloy steel. (a) Low magnification of OM image; (b) magnified OM image inserted with high-magnification SEM image

Fig. 5. Microstructure of LAM 12CrNi2 alloy steel after isothermal quenching at 200-400 ℃ for different time

Fig. 6. SEM images of LAM 12CrNi2 alloy steel after isothermal quenching at 200 ℃. (a) 5 s; (b) 20 s

Fig. 7. TEM images of LAM alloy steel isothermal quenching at temperature 200 ℃ for 20 s. (a) Bright-field image; (b) selected-area electron diffraction patterns of area 1; (c) selected-area electron diffraction patterns of area 2

Fig. 8. Stress-strain curves of samples before and after isothermal quenching

Fig. 9. Tensile fracture morphologies of LAM steel before and after heat treatment. (a)-(c) As-deposited state; (d)(e) 860 ℃/30 min+200 ℃/10 s; (f)(g) 860 ℃/30 min+200 ℃/20 s; (h)(i) 860 ℃/30 min+400 ℃/20 s