Tailoring Microstructure and Architecture to Build Ceramic Components with Unprecedented Damage Tolerance

Descripción del proyecto

Componentes cerámicos con tolerancia a los daños

Desde bioimplantes para artroplastias de cadera a actuadores para dispositivos de inyección en vehículos, la cerámica avanzada puede combinarse con metales, polímeros u otros materiales cerámicos para desarrollar sistemas funcionales y estructurales con magníficas propiedades. El proyecto financiado con fondos europeos CeraText mejorará la funcionalidad de los sistemas previniendo la formación de grietas en piezas cerámicas frágiles. Desarrollará «diseños multicapa» combinando microestructura con arquitectura para alcanzar el nivel de tolerancia a los daños propio de materiales naturales como la madera, el hueso o las conchas de molusco. Para ello, el proyecto adoptará un método biomimético que imita la estructura jerárquica de las conchas. Se prevé que CeraText defina unas directrices de diseño que permitan la producción de los futuros componentes cerámicos en 3D, elaborados mediante procesos como la fabricación por adición.

Objetivo

Advanced ceramics are often combined with metals, polymers or other ceramics to produce structural and functional systems with exceptional properties. Examples are resistors and capacitors in microelectronics, piezo-ceramic actuators in car injection devices, and bio-implants for hip joint replacements. However, a critical issue affecting the functionality, lifetime and reliability of such systems is the initiation and uncontrolled propagation of cracks in the brittle ceramic parts, yielding in some cases rejection rates up to 70% of components production.
The remarkable “damage tolerance” found in natural materials such as wood, bone or mollusc, has yet to be achieved in technical ceramics, where incipient damage is synonymous with catastrophic failure. Novel “multilayer designs” combining microstructure and architecture could change this situation. Recent work of the PI has shown that tuning the location of “protective” layers within a 3D multilayer ceramic can increase its fracture resistance by five times (from ~3.5 to ~17 MPa∙m1/2) relative to constituent bulk ceramic layers, while retaining high strength (~500 MPa). By orienting the grain structure, similar to the textured and organized microstructure found in natural systems such as nacre, the PI has shown that crack propagation can be controlled within the textured ceramic layer. Thus, I believe tailored microstructures with controlled grain boundaries engineered in a layer-by-layer 3D architectural design hold the key to a new generation of “damage tolerant” ceramics.
This proposal outlines a research program to establish new scientific principles for the fabrication of innovative ceramic components that exhibit unprecedented damage tolerance. The successful implementation of microstructural features (e.g. texture degree, tailored internal stresses, second phases, interfaces) in a layer-by-layer architecture will provide outstanding lifetime and reliability in both structural and functional ceramic devices.