Self-lubricating properties of digital light processing 3D printed porous AISI 316L stainless steel by impregnated PAO10 oil

Porous oil-containing materials achieve self-lubrication through pore-stored oil, making them suitable for demanding applications such as vacuum, high-speed and maintenance-free systems. While 3D printing combines the advantages of complex structure fabrication and performance regulation, research on its application in porous metal fabrication remains limited. This study integrates digital light processing (DLP) 3D printing with vacuum impregnation to fabricate porous AISI 316L stainless steel materials impregnated with PAO10 oil. By adjusting the slurry solid loading (82 wt.%–88 wt.%) and sintering temperature (1200°C–1350°C), 12 groups of materials with controlled porosity were fabricated. DLP technology enables precise regulation of oil impregnation rate (10 wt.%–40 wt.%) and achieves high open porosity exceeding 80%. The mechanical properties improve progressively with elevated process parameters, accompanied by fracture morphology evolution from interparticle fractures to dimple-dominated ductile fractures. Both oil impregnation rate and mechanical strength are critical to self-lubricating performance, showing a notable synergistic effect. Optimal self-lubricating performance requires a tensile strength of 250 MPa and an oil impregnation rate of 15%. S1-1350°C sample demonstrates the best performance, with a friction coefficient of 0.09 and an ultralow wear rate of 3.30 × 10−6mm3/(N m) under a 30 N load and 0.04 m/s sliding speed against Si3N4counterpart. These results will provide valuable insights for advancing the digital design and precision manufacturing of self-lubricating porous materials.