TY  - JOUR
AU  - Wallis, David
AU  - Harris, Joe
AU  - Böhm, Corinna F.
AU  - Wang, Di
AU  - Zavattieri, Pablo
AU  - Feldner, Patrick
AU  - Merle, Benoit
AU  - Pipich, Vitaliy
AU  - Hurle, Katrin
AU  - Leupold, Simon
AU  - Hansen, Lars N.
AU  - Marin, Frédéric
AU  - Wolf, Stephan E.
TI  - Progressive changes in crystallographic textures of biominerals generate functionally graded ceramics
JO  - Materials advances
VL  - 3
IS  - 3
SN  - 2633-5409
CY  - Cambridge
PB  - Royal Society of Chemistry
M1  - FZJ-2022-00784
SP  - 1527
PY  - 2022
AB  - Biomineralizing organisms are widely praised for their ability to generate structural materials with exceptional crystallographic control. While earlier studies highlighted near-to single-crystalline biominerals, complex polycrystalline features are more widespread yet challenging to account for. Here, we propose that biominerals whose crystal texture varies with depth are functionally graded materials. Using the exemplary case of the nacro-prismatic pearl oyster Pinctada margaritifera, we demonstrate systematic textural changes in a biogenic ceramic. This bivalve employs three synergistic mechanisms to generate a texture gradient across its outer calcitic shell layer. This prismatic layer transitions from an initially weakly-textured to a strongly-textured material. Such changes in texture cause a variation in Young's modulus normal to the shell, owing to the anisotropic mechanical properties of the composing crystallites. Based on finite-element simulations and indentation experiments on the bivalve shell, we conclude that such graded bioceramics yield intrinsic toughening properties similar to those found in compositionally-graded synthetic materials. Notwithstanding, the gradation concept of Pinctada margaritifera is unparalleled among synthetic materials as it rests solely upon elastic anisotropy, making oyster shells potential blueprints for future bioinspired functional materials and damage-resistant ceramics.
LB  - PUB:(DE-HGF)16
UR  - <Go to ISI:>//WOS:000739565700001
DO  - DOI:10.1039/D1MA01031J
UR  - https://juser.fz-juelich.de/record/905543
ER  -