Preparation method and mechanical properties of high-strength, high-toughness, and wear-resistant Cu/316L interpenetrating composites based on ink direct writing and melt infiltration

Inspired by the three-dimensional interpenetrating structure of natural materials in nature, this work aimed to explore and develop metal matrix composites that combine high performance with complex structures. A method combining Direct Ink Writing (DIW) technology and pressureless melt infiltration process was employed. First, a porous 316L metal skeleton with a preset configuration was precisely printed using DIW technology. Then, by leveraging the excellent wettability between Cu and 316L at high temperatures, the molten Cu was driven by capillary force to infiltrate into the pores of the skeleton, forming a dual-phase three-dimensional interpenetrating composite structure. The effects of different sintering temperatures on the microstructure and compressive strength of the porous 316L metal skeleton, as well as the mechanical properties and wear resistance of the composite, were investigated. The results showed that at a sintering temperature of 1200℃, the skeleton surface was relatively smooth and flat, while at 1400℃, the maximum compressive strength was achieved when loaded perpendicular to the layer stacking direction (T direction) of the skeleton. As the sintering temperature increased, both the surface roughness and compressive strength of the skeleton increased. The mechanical properties of the composite exhibited significant anisotropy, with excellent flexural strength demonstrated when loaded in the T direction, which increased with the rotation angle of the printed skeleton. When loaded parallel to the layer stacking direction (L direction), the flexural strength decreased, but the strength differences among samples with different rotation angles were relatively small. Additionally, the composite exhibited good wear resistance.