Near-net shaping of laminated Al/Al2O3 composites by direct ink writing and pressure infiltration

Abstract

We developed a novel approach involving a combination of direct ink writing and magnet-assisted pressure infiltration to the fabrication of near-net-shape laminated Al/Al2O3 composites. Furthermore, we investigated the effects of the sintering temperature and metal layer thickness on the microstructure and mechanical properties of the resultant composites. With an increase in the sintering temperature and a decrease in the metal layer thickness, the composite's bending strength increased, but its crack-growth toughness decreased. Notably, the fracture behavior of the composite depended on the structural orientation. When the loading direction was parallel to the ceramic lamellae, a crack was initiated in the metal layer since the Al layer was weaker than the ceramic layer. By contrast, a crack was initiated in the ceramic layer when the loading direction was perpendicular to the ceramic lamellae. The toughening mechanisms mainly included plastic deformation of the metal matrix, crack deflection, and ligament bridging.