In many fields of industry, materials science and engineering is the driving force pushing limits of applications. Innovative branches, such as aerospace, biomedical, nuclear fusion and tools engineering, increasingly replace traditional materials by tailored ones. Tailoring materials is possible on many scales. A popular method is mixing micrometre-sized powders of different materials and consolidating the powder mix to so-called composite materials. In such composite materials, the tailored properties are strongly influenced by the interfaces of the constituents. For instance, heat conduction and strength are usually low when interfaces are weak.
In my Gateway Fellowship (GF) project, I will study the impact of interfaces on thermo-physical and mechanical properties in detail, using the composite system iron/tungsten (Fe/W). A variety of composites, differing in the Fe/W ratio, fabrication parameters and heat treatments will be prepared. Following a microstructural evaluation, microscopic cantilevers will be cut from the composites. Using a micro-actuator, implemented in a scanning electron microscope, the cantilevers will be bent until they fracture at the weakest spot – the Fe/W interface.
The combination of diverse sample preparation and specialised testing set up allows a unique assessment of interfaces in such material systems. Simultaneous microscopic observations and bending experiments allow relating interface qualities, fabrication parameters and macroscopic properties. The outcome of my research will help understanding how interfaces influence composite materials properties and how to fine-tune fabrication parameters to adjust specific properties.
During my GF project, I will be working with Dr David Armstrong who is Professor and Royal Academy of Engineering Research Fellow at the Department of Materials of the University of Oxford. His work is centred around developing mechanical testing techniques at the nano and micro scale. While this topic has only started to gather attention, he looks back at years of expertise and numerous publications in important journals.