Current Research Projects

3D and 4D imaging of materials

Ria L Mitchell

I run the Sheffield Tomography Centre (STC) X-ray imaging facility at the University of Sheffield, and am interested in 3D and 4D imaging across a range of geological and biological materials, as well as human-made materials. Of particular interest is using our selection of mechanical testing rigs to create 3D and 4D datasets from in-situ tensile and compression experiments, and correlative microscopy across numerous imaging and analytical techniques at various length scales and across dimensions (e.g. X-ray CT/XRM, SEM, SEM-EDS, EBSD, FIB-SEM, optical microscopy). Particular research interests include early plant evolution and their effect on soil development, weathering, and biogeochemical cycling, palaeosols, and bioinspiration for human-made materials.

Characterising Micro- and Nano-mechanical Properties of Additive Manufacture Alloys

İdris Tuğrul Gülenç

Currently, my research is about exploring the effects of different processing conditions on the surface finish, tribological performance and mechanical properties of additively manufactured alloys. It involves manufacturing parts using selective laser melting, characterisation of their mechanical properties, and testing their tribological response depending on different surface characteristics. The research aims to identify the mechanism behind surface topography, improve the usability of additive manufacture alloys in as-built condition and define the best tribological response depending on processing parameters.

Investigating high voltage Li-ion battery (mainly cathode) degradation via in-situ microscopy funded by the Faraday Institution

Ashutosh Jangde

This work aims to implement and develop in-situ SEM mechanical testing methodologies to evaluate the mechanical resilience and cracking behaviour of a range of modern, nickel-rich Li-ion battery chemistry electrodes as a function of its electrochemical history. This mechanical degradation will be corroborated with various structural, chemical, microstructural, and electrochemical characterization techniques.

Structural Degradation Studies of High Voltage Li-ion Battery Materials

Laura Wheatcroft

High voltage Li-ion battery materials are being developed for new high energy storage applications such as electric vehicles and grid scale storage. Higher operating potentials could reduce the number of cells needed, and hence the price of large batteries. However, high operating potentials lead to degradation mechanisms.

My research involves using different microscopy techniques to study degradation in high voltage Li-ion battery materials. I have used electron energy loss spectroscopy (EELS) to visualise lithiation mechanisms (how Li shuttles in and out of particles during cycling) by looking at changes in Co oxidation state. I have also used helium ion microscopy and secondary ion mass spectrometry (HIM and SIMS) to analyse the surface layers which result from the degradation of electrolyte when operating at high potentials.

My research has been sponsored and performed in collaboration with Johnson Matthey. The HIM and SIMS work was funded by PicoFIB and performed with HZDR, Germany.

The Investigation into Silicon Based Nano Contacts

Arron Bird

Looking to explore new and innovative in-situ nano-dentation techniques as well as more traditional wear testing the main aim of this project is to map and explore the behaviour of Silicon based materials at a nano scale. Various coatings and wear environments will be tested in an aim to complete a full map of the behaviour of Si at a Nano level.