Inhomogeneous elasticity to toughen brittle systems
Lead Research Organisation:
University of Cambridge
Department Name: Materials Science & Metallurgy
Abstract
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.
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.
People |
ORCID iD |
Nicholas Gwilym Jones (Primary Supervisor) | |
Julia Puerstl (Student) |
Publications
Pürstl J
(2021)
On the extraction of yield stresses from micro-compression experiments
in Materials Science and Engineering: A
Pürstl J
(2023)
On the Plasticity of Layered Crystals