Fig. 1 a Morphology of the gas-atomized powders, b image of the SLM-produced 316L samples under argon protection, c a sketch of the heat treatment process, d laser scanning strategy, and e sketch of the as-fabricated specimens which the tensile specimen extraction scheme and the position selected for microstructure observation are clearly shown

Fig. 2 Optical microstructures of heat-treated samples at temperatures of 1328 K, 1123 K, and 873 K, respectively. a, c, e Top view; b, d, f side view

Fig. 3 SEM images of SLM-processed samples heat-treated at various temperatures

Fig. 4 EDS analysis result of the white particles

Fig. 5 Grains maps of as-built and annealed 316L SS samples. The grain maps on the side surfaces are similar to each other; hence only one map paralleling to build direction is presented in these figures. The grain size distribution is obtained from the top surface in the image. a As-built, b 873 K, c 1123 K, d 1328 K. e, f, g, h Corresponding grain size distributions for as-built, 873 K, 1123 K, and 1328 K sample, respectively

Fig. 6 Summary of average grain size and fraction of LAGBs as a function of annealing temperature. a Average grain size, b fraction of LAGBs

Fig. 7 Band contrast maps of as-built and annealed 316L SS samples. The misorientation angle distribution is obtained from the top surface in the image. A misorientation angle between 2° and 5° is colored in red, 5°-15° is colored in green, whereas 15°-180° is colored in blue. a As-built, b 873 K, c 1123 K, d 1328 K. e, f, g h Corresponding misorientation angle distributions for as-built, 873 K, 1123 K, and 1328 K sample, respectively

Fig. 8 Effect of annealing temperature on the mechanical property of SLM-processed parts. a and b Representative engineering tensile stress-strain curves and the corresponding true stress-true strain curves at various annealing temperatures. c and d Summary of tensile properties and microhardness of SLM-produced parts as a function of annealing temperature, respectively. e Variation of yield strength with annealing temperature including our work and data reported in the literature. The blue dashed lines indicate the general variation trend. f Ultimate tensile strength as a function of annealing temperature based on reported values in the literature. g Hardness as a function of annealing temperature for our work and researches reported in the literature. h Comparison between the obtained mechanical properties in this study and wrought 316L (including cold finished and solution treated) reported in the literature. The red dashed lines indicate the general trend of mechanical response for samples annealed at different temperatures. The above data are collected from references [2,7,19,22,25,26,28,35,36,37,39,40,41,42,43,44,45,46,47]

Fig. 9 Effect of annealing temperatures on strain hardening behavior of SLM-produced parts. a Normalized work hardening rate curves as a function of annealing temperature, b logarithmic plots of true stress versus true strain for the SLMed parts at various annealing temperatures

Fig. 10 Fracture surfaces of SLMed 316L SS at different annealing temperatures

Fig. 11 a Representative engineering tensile stress-strain curves at different strain rates. b Summary of tensile properties of SLM-produced part at different strain rates. c Logarithmic plots of true stress versus true strain for the SLMed material at different strain rates. d Logarithmic plots of tensile strength versus strain rate for the SLMed material

Fig. 12 Optical micrographs of polished sections showing porosity in as-built sample

Fig. 13 Fracture surfaces of SLM-produced parts at different strain rates