  The architectures of biological hard materials reveal finely tailored complex
assemblies of mineral crystals. Numerous recent studies associate the design of
these local assemblies with impressive macroscopic response. Reproducing such
exquisite control in technical ceramics conflicts with commonly used processing
methods. Here, we circumvent this issue by combining the recently developed
Magnetically-Assisted Slip Casting (MASC) technique with the well-established
process of Templated Grain Growth (TGG). MASC enables the local control over
the orientation of platelets dispersed among smaller isotropic particles. After
a high temperature pressure-less treatment, the grains of the final ceramic
follow the same orientation of the initial platelets. This combination allows
us to produce 95 % dense alumina part with a grain orientation following any
deliberate orientation. We successfully fabricated microstructures inspired
from biological materials with ceramics that present periodically varying
patterns with a programmable pitch of a few tens of microns. We confirmed the
capacity of the process to tailor local mechanical properties through local
grains orientation using micro-indentation. This micrometer scale control over
the local mechanical properties could be applied to adapt ceramic structures to
complex loads using this inexpensive and scalable process. In systems where
functional properties also depend on anisotropic grain orientation, the
principle presented here could enable the creation of new multifunctional
ceramics.
