Mechanical behavior of 3D printed stainless steel evaluated by miniaturized small punch testing

Additive manufacturing (AM) has enabled the production of intricately shaped, high-performance components, yet the characterization of new AM alloys is often challenged by high material demands and lengthy test protocols. The Small Punch Test (SPT), as a miniaturized mechanical test, offers a practical solution for situations where specimen volume is restricted, reducing both material use and evaluation time. While SPT has been broadly validated for conventional alloys, its application to 3D-printed materials, such as selective laser melted (SLM) stainless steels, remains limited and non-standardized. In this work, the mechanical response of SLM-fabricated SS 316L is evaluated via miniaturized SPT specimens. Key factors including surface roughness, punch geometry, and displacement rate are systematically investigated for their influence on test outcomes. Smaller punch diameters generated higher peak loads due to localized stress concentration, whereas lower displacement rates yielded smoother and more stable load–displacement curves. A suite of empirical models for ultimate tensile strength (UTS) prediction from SPT data is developed and benchmarked against standard tensile test values. The proposed multi-parameter model, incorporating surface and process variables, achieves excellent agreement with experimental results and surpasses the accuracy of conventional SPT models. These findings underscore the critical impact of print orientation and surface condition on SPT derived mechanical properties, and demonstrate the capability of SPT as a rapid and efficient tool for the qualification of 3D-printed alloys. The methodology developed here offers a streamlined path for mechanical assessment and process optimization in additive manufacturing.