The 177th Structural Materials Seminar: Dr. Luke Hewitt (Senior Materials Scientist United Kingdom Atomic Energy Authority)
On October 06, 2025, Dr. Luke Hewitt, (Senior Materials Scientist United Kingdom Atomic Energy Authority) gave a lecture at NIMS as the 177th Structural Materials Seminar.
Dr. Luke Hewitt (front row, 3rd from right)
- Date and Time
-
Monday, Oct. 6, Mon, 2025. 13:30～14:30
- Location
-
Conference Room, 5th Floor, Advanced Structural Materials Building, NIMS Sengen Site
- Title
-
In-situ strain measurement of micro-mechanical specimens using digital image correlation
- Speaker
-
Dr. Luke Hewitt, Senior Materials Scientist United Kingdom Atomic Energy Authority
Abstract
The performance of materials under the harsh environments anticipated within a fusion reactor will be key to its success. In the absence of a representative environment such as a fusion energy spectrum neutron source, the traditional methods of materials assurance through empirical testing are not possible and alternatives must be sought.
Design by Fundamentals is a project to develop mechanistically informed, physically justified crystal plasticity models to link microstructure to mechanical properties, and predict the behaviour of materials in untestable environments. It relies on analysis of samples subject to surrogate irradiations such as in materials test reactors or with charged particles, which are typically not in the correct geometry for conventional, standardised mechanical testing and require the use of miniaturised specimens or micro-mechanical testing. Here we present work on the development of high fidelity micro-mechanical experiments to provide data for model calibration.
It is well known that there are challenges around alignment and knowledge of the exact boundary conditions in such micro-mechanical tests, and these can influence the measured response. This talk will present the use of Digital Image Correlation (DIC) to track displacements during testing of micro-pillar and micro-tensile specimens inside an SEM, enabling accurate strain measurement to mitigate these issues. Mapping of strain to study the effects of irradiation damage on deformation will also be presented.