Abstract:
An attempt is made to fabricate nacre-type alumina/epoxy (cerepoxy) composites using ice-templated alumina
scaffolds. A polydimethylsiloxane (PDMS) wedge with varying angles (0◦, 5◦, 10◦, and 20◦) is used to modulate
the temperature gradients during the freezing. While a 2D nucleation is observed in uni-directional freezing (0◦
wedge angle), bi-directional freezing in non-zero wedge angles shows 1D nucleation. The lamellae thickness and
interlamellar spacing increase with the increase in PDMS wedge angle. Moreover, the density of scaffolds varies
along the freezing direction, with denser microstructure recorded at the bottom location (closer to the cold
finger). The quasi-static and high strain rate compression testing reveals the anisotropy in the compressive
mechanical properties of cerepoxy samples. The compressive strength and energy-absorbing capacity increase at
higher loading rates. Finally, the present study establishes the structure-property relationship and shows that bidirectional freezing is an efficient route to design and fabricate cerepoxy composites having nacre-type
microstructure
