Synergistic enhancement of properties via in-situ alloying 316L-SiC composites and multiscale mechanisms

Owing to its superior mechanical properties and corrosion resistance, 316L stainless steel is widely used in medical and industrial applications. Achieving a simultaneous improvement in the strength–ductility balance, wear resistance and corrosion resistance of 316L, however, remains challenging. Laser Powder Bed Fusion (L-PBF) has demonstrated considerable potential both for fabricating complex, fine-scale 316L architectures and for enabling in situ alloying. In this study, 316L was alloyed with silicon carbide (SiC) ceramic particles (average grain size 1 μm) via L-PBF, producing a refined, heterogeneous composite microstructure. Relative to L-PBF-processed 316L without SiC, the ultimate tensile strength of the 316L-4SiC sample reached 1.2 GPa, an increase of approximately 105.5%, while preserving a strain exceeding 12%. Vickers hardness rose from 271.183 HV to 419.913 HV, an increase of about 55%. Tribological performance was also substantially improved: wear-track depth fell from 101 μm to 74 μm (a reduction of approximately 27%) and the wear rate reached as low as 1.17 × 10 mm 3 /N·m, representing an improvement of roughly 51%. This study investigates the synergistic mechanisms that improve the mechanical properties and corrosion resistance of 316L stainless steel. The results show that the in-situ alloying method and the reinforcing phase particles interact closely, providing useful guidance for the design of 316L stainless steel with specialised functions.