Inhomogeneous elasticity to toughen brittle systems

Ceramics are widely used as protective coatings in high temperature applications. However, the lifetime of these materials is limited by their brittleness, and they often fail by cracking.
A possible method to increase the fracture resistance is by making plastic flow easier. Recent studies based on density functional theory calculations showed that the yield stress can be significantly reduced if a crystal unit cell elastically deforms in an inhomogeneous manner. It has been demonstrated that the basis for this behaviour lies in electronegativity differences within the unit cell, which lead to a shift of electron density. The regions with lower electron density allow slip to occur more readily.
The project is designed to understand the limits of this behaviour and the structures that are likely to lead to materials with higher toughness. Moreover, it will be explored how other properties (e.g. creep resistance, thermal stability) may be controlled, eventually aiming the development of novel strategies for controlling strength.