Tunable architectures in Al/Al2O3 composites for enhanced damage tolerance using zirconium acetate-mediated ice-templating

Achieving lightweight, robust, and resilient materials is a sought-after goal, yet concurrently achieving these attributes presents a substantial challenge. A biomimetic design approach opens doors to innovative possibilities in this domain. In this paper, we use the ice-shaping properties of zirconium acetate (ZRA) to obtain Al/Al2O3 composites with tunable architectures through freeze casting and pressure infiltration. The concentration of ZRA in the initial slurry is critical in controlling the final structure of the composites. The composites' bending strength, compressive strength, and crack-initiation fracture toughness KIc improve with increasing ZRA concentration in the initial slurry. Interestingly, the crack-extension fracture toughness KJc demonstrates an initial decrease followed by subsequent improvement. In addition, the relationship between cracking mode and structural features in the composites is elucidated to explain the underlying strengthening and toughening mechanisms. This tunable and scale-able ice-templating and manufacturing approach opens new doors for developing high-performance metal-ceramic composites.