ERC - Shine

Summary of published results

On the technique side: 

• our article published in PLOS One describes the infrastructure for SHINE, namely the Laplace Project

• we have developed protocols for hydrogen charging of site specific specimens  in part using a novel gas-charging chamber that was developed in-house, in part in colalboration with Cameca, to heat-treat atom probe specimens in various gaseous environments. 

• we also keept developing approaches for APT and field-ion microscopy, looking at vacancies in particular, better understand imaging by FIM to target true atomic-resolution closely with colleagues from the GPM in Rouen, and also possible sources of energy deficits and trajectory aberrations assocaited to dynamic effects from the high-voltage pulsing. We also looked into using machine-learning approaches to help automate peak identification in mass spectra.

• the possibility of using cryogenic temperatures opens a possible route for the analysis of nanoparticles in ice, which would require plunge freezing. Dr Rusitzka joined the group for over a year, and used her background in biology to try set up capacity to perform such experiments on protein fibrils - preliminary results were published in Scientific Report, although results in ice will take more time to interpret.

• we are following up on the use of ice as a carry medium for nanomaterials - see our preprint on the analysis of frozen water by APT which was later published in Science Advances.

• We also kept investigating the deformation mechanisms in single crystal superalloys and polycristalline superalloys, and the next steps will be to investigate how these are affected by the presence of hydrogen

On the analysis of structural materials:

• our preliminary results on H in Ti published in Acta Materialia, which showed us that we could analyse bulk hydride phases but also that much hydrogen was introduced during the preparation of specimen by focused-ion beam. We studied a range of model and industrial alloys, with a range of composition – this was partly done in collaboration with Prof. Moody at Oxford and Prof. Dye at Imperial College London – and we hinted to an influence of the level of Al in the alloy on the pick-up of H. 

• This uncontrolled ingress of H was used to load samples of Ti-Mo with different microstructures, as shown in this letter in Scripta Materialia;

• we demonstrated that these issues can be avoided by performing the final steps of the specimen preparation at cryogenic temperatures, as shown in this article in Nature Communications and this is particularly relevant to the preparation of specimens from Ti- and Ti-based alloys in which hydrides have sometimes been confused for a new FCC-allotrope of Ti.

• We followed up on this with work aiming to disprove the existence of fcc-Ti - which we show is simply a Ti-hydride that has been mislabelled as fcc-Ti in many articles - this is discussed in this Scripta Materialia article.

• we started studying stable hydrides and deuterides of Zr, in a collaboration with Dr Ben Britton from Imperial College London, and we revealed interesting processes taking place between the hydride and the metallic matrix, namely a redistribution of Sn and the presence of an interfacial region with a different crystal structure and composition – published in Scripta Materialia – more on this front will come in the future;

• We went on to perform a systematic study of how well hydrogen or deuterium could be quantified in Zr-based hydrides and Ti-hydrides and laid out some of the associated challenges.

• We worked on pearlitic wire and optimised our workflow to minimise interference with – this is described in details in this article in Acta Materialia along with some implications from a materials science and resistance to hydrogen embrittlement standpoint. 

• We worked together with colleagues from other groups at MPIE to develop new steels that are resistant to hydrogen-embrittlement, by adjusting the composition of the alloy to maintain a high number density of austenite islands that act as hydrogen traps and again crack propagation – the paper is in Nature Materials and was discussed as a highlight on CORDIS.  

Finally, within SHINE, we started working jointly with groups at MPIE on the direct reduction of iron ore by hydrogen:

• we first looked at the evolution of the microstructure and atomic-scale chemistry on iron ore reduced  with hydrogen at 700°C  – paper is here

• and then when a H-containing plasma is used for the reduction- paper is here 

more has been  done on this front and can now be found in the literature :)