Preparation of laminated Cr3C2/Cu composites by direct ink writing and pressureless infiltration

Cr3C2/Cu composites with laminated interpenetrating structures were prepared by direct ink writing and pres-sureless infiltration, exploiting the excellent wettability of Cr3C2 by molten Cu and using the concept of near-net shaping. The laminated structures had alternating soft and hard lamellae, and they imparted significant anisotropy to the composites. The composites had the highest bending strength when the loading plane was parallel to the lamellar orientation, and they showed the highest toughness when the loading plane was perpendicular to the lamellae and their stacking direction. Furthermore, ductile fracture characteristics were observed in both these cases, while brittle fracture characteristics were apparent when the loading plane was perpendicular to the lamellae but parallel to their stacking direction. The fracture behavior of the composites was analyzed on the basis of in situ observations of crack initiation and propagation. The toughening was mainly caused by internal and external processes such as plastic deformation of the ductile copper layer, crack deflection, ligament bridging, and multiple cracking. Overall, this work presents a simple, economical, and scalable route based on the concept of near-net shaping and a three-dimensional-printing technique for the preparation of ceramic/metal composites with desired structures.