Rate-Dependent and Temperature-Sensitive Behavior of Selective Laser Melting 316L Stainless Steel: Dynamic Impact Modeling of a Hat-Shaped Specimen

This study systematically investigates the mechanical properties and failure behavior of selective laser melted (SLM) 316L stainless steel (SS316L), with particular emphasis on the effects of strain rate, temperature, and stress state. Vertically oriented SS316L specimens were fabricated using SLM technology and subjected to comprehensive mechanical characterization. The experimental program included evaluating static tensile properties at elevated temperatures and analyzing notch sensitivity under varying stress states. The results demonstrate that SLM SS316L displays ductile failure characteristics at 24 °C, along with notable strain-hardening and temperature-softening behaviors. However, it manifests a mixed mode of failure at 600 °C, exhibiting both ductile and brittle characteristics, which can be attributed to the effects of dynamic strain aging. A significant notch-strengthening effect was observed, with notched specimens showing superior tensile strength compared to smooth specimens. Moreover, an inverse relationship was identified between notch size and tensile strength (R_m), accompanied by enhanced fracture toughness (K_c). Dynamic mechanical testing revealed pronounced strain rate, temperature sensitivity, and notable tension–compression asymmetry in SLM SS316L. The Johnson–Cook (JC) parameters for yield and failure were established based on the experimental data. The study further investigated adiabatic shear band (ASB) formation through numerical analysis of hat-shaped specimens under dynamic compression. The numerical simulations correlated with previous experimental observations across multiple scales, accurately capturing shear stress–strain responses, macroscopic deformation patterns, and ASB characteristics. These results provide fundamental insights into the mechanical behavior of SLM SS316L, establishing a foundation for its reliable implementation in engineering applications requiring dynamic loading performance.