This group is led by Dr Stella Pedrazzini.

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Developing in-situ and ex-situ approaches to explore corrosion mechanisms in industrial systems

Dr Chris Bilsland (Research Associate)

Co-supervised by Prof Mary Ryan

In collaboration with Shell and QNRF

 

Development of methods to explore and understand the underlying mechanism of corrosion occurring within different industrial systems and investigating preventative solutions. Implementing correlative methods including Raman, EDS and SEM with standardised corrosion experiments with the application of analytical and statistical approaches to the experimental and model system data will probe the mechanisms for these systems and provide the basis for understanding the preventative methods available.

Effect of alloying additions Mo and W on microstructural properties and hot corrosion of Ni-based superalloys

Cynthia Rodenkirchen (Research Postgraduate)

Co-supervised by Prof Mary Ryan

In collaboration with Rolls-Royce plc

 

 

Ni-based superalloys, commonly used e.g. in turbines for aircraft engines, are an important material class for operations at high temperature and high stress. They exhibit high mechanical strength and resistance to thermal creep deformation even at temperatures close to their melting points. Another essential characteristic of these superalloys is corrosion resistance. By investigation of several superalloys with varying Mo and W compositions, this study aims to understand the effect of Mo and W on type-2 hot corrosion of Ni-based superalloys.

Corrosion of additively manufactured Ti alloys for custom orthopaedic implants

Jessica Tjandra (Research Postgraduate)

Co-supervised by Dr Enrique Alabort, Dr Daniel Barba and Dr Minh-son Pham

In collaboration with Alloyed Ltd

Member of Advanced Characterisation of Materials CDT

Additively manufactured (AM) titanium alloys are increasingly used in biomedical applications, such as in bone replacements and joint implants. This project aims to understand the degradation mechanisms of AM titanium alloys when exposed to body fluid, under static exposure, corrosion wear and corrosion fatigue. Of particular interest is the effect of different AM lattices on the mechanical properties and material performance of these alloys. Advanced characterisation techniques such as atom probe tomography will be utilised to investigate corrosion mechanisms due to body fluid in AM Ti lattices.

Under deposit corrosion

Parul Bishnoi (Research Postgraduate)

Co-supervised by Prof Mary Ryan

In collaboration with Shell

 

Corrosion-related failures have substantial impacts on industrial plants, including environmental, safety, and economic consequences. One particular concern is Under Deposit Corrosion (UDC), which poses a significant risk to steam generator tubes. Maintaining the structural integrity of these tubes is crucial for the energy sector in order to mitigate expensive part replacements and enhance sustainability. However, understanding the fundamental mechanisms of UDC is challenging due to its unpredictable and highly localized nature, as well as experimental limitations. This thesis aims to uncover the mechanism behind UDC by subjecting a low Cr-Mo steel alloy sample to autoclave treatment under varying parameters, simulating boiler-like conditions. The formation of a multi-laminate layer, a characteristic feature of this corrosion type, will be studied in relation to different parameters.

Alloying for impurity tolerance

Katlo Batsile (Research Postgraduate)

Co-supervised by Dr Daniele Dini and Prof Fionn Dunne

Member of Science Solutions for a Changing Planet Doctoral Training Partners & Transition to Zero Pollution

 

Recycling is an important aspect of the steel and iron industry's effort to attain circularity. However, one of the challenges pertains to the presence of impurity elements which accumulate with continued recycling, causing the deterioration of important mechanical properties like ductility and impact toughness of the steel. As a result, recycled steel has limited potential in high-value applications. In uncontrolled amounts, copper can be particularly detrimental, and understanding its effects on steels, the influence of elemental additions, and thermo-mechanical processing on mechanical properties is key to the design of impurity tolerant alloys. Through the use of advanced microscopy techniques and atom probe tomography, we aim to characterise the segregation of this impurity element and any changes as a result of alloying additions.

Towards intelligent monitoring and efficient operation of steam-methane reformers: Measurement and modeling of variation in emissivity

Jiaqi Liu (Research Postgraduate)

Co-supervised by Prof Mary Ryan

In collaboration with Dr. Wouter Hamer (SRTC), Dr. Nick Laycock (QSRTC) and Dr. Bilal Mansoor (TAMUQ)

 

Under the background of the energy transition, steam-methane reforming (SMR) plays an important role as a key method to produce blue hydrogen. To prevent creep damage of reformer tubes, the surface temperature of the reformer tubes is monitored to diagnose material conditions and predict the tube lifetime, usually by infrared (IR) thermography. However, the emissivity of the tube changes with surface properties changes because of material oxidation and this then leads to inaccuracy of IR thermography, which is the problem that this project focuses on. High-temperature oxidation on pure metals (Fe, Cr, Ni and Nb) and SMR tube material (HP40 steel) is replicated in controlled conditions, and all pristine, oxidised, and ex-service materials are tested for surface properties by characterisation techniques and for total-hemispherical emissivity according to standard ASTM C835-06. The aim of this PhD project is to correlate surface conditions and emissivity evolution, then provide baseline data as guidance for IR thermography in the real world.

 

New approaches to understanding hydrogen embrittlement of steels

Chao Sun (Research Postgraduate)

In collaboration with Shell

 

 

 

The project aims to develop a fundamental understanding of hydrogen embrittlement in steels via various characterization techniques including cryogenic Atom Probe Tomography (APT). Hydrogen is a promising candidate for fossil fuels whose combustion product, water, is environmentally friendly. One of the biggest challenges of the hydrogen economy is storage and transport. A highly cost-effective storage technology is to store hydrogen in steel canisters under high pressure and low temperature. However, they may be embrittled by the cryogenic temperatures and hydrogen exposures- or the synergistic effects of both. Hydrogen embrittlement in steel at cryogenic temperatures is poorly understood, thus material selection or bespoke alloy development remains challenging. With atom-scale resolution characterization methods like APT, an improved fundamental understanding of the processes of hydrogen dissolution in the metal, and the role of microstructural features that act as hydrogen trap sites, will assist in screening steels for hydrogen service. This project will therefore focus on the experimental investigation of hydrogen dissolution, diffusion, and distribution in different steels – with the steels studied and characterized under cryo-conditions. The experimental work will be supported by numerical modelling, leading to a workflow for characterizing candidate steels for hydrogen service.

Atom probe tomography and microscale mechanical testing of neutron irradiated PWR reactor pressure vessel steel

Ryan Stroud (Research Postgraduate)

Co-supervised by Dr Mark Wenman

In collaboration with EdF Energy

Member of Nuclear Energy Futures CDT

My project uses the hot cells and active focus ion beam facilities at the Materials Research Facility (MRF) in Culham and the active materials atom probe facility at Oxford University to study irradiated material from a PWR. The aim is to study how the neutron irradiation damage has evolved at the nano-scale and compare how microstructural changes, made by pre-straining the material, before irradiation, has changed the radiation response of the steel. My end goal is to use the results to extend the lifetime of current LWRs, which in turn will help mitigate the release of CO2 emissions.

H2S cracking in pipeline TMCP steel

Sarah Hiew Sze Kei (Research Postgraduate)

Co-supervised by Dr Ben Britton, Dr Thibaut Dessolier, Willem Maarten van Haaften

In collaboration with Shell Global Solutions International B.V.

 

Thermo-Mechanical Control Process (TMCP) steels were used as pipeline structures within the oil and natural gas industry due to its high strength, toughness and weldability. Despite being long accepted for operation, there is a risk that TMCP steels can be susceptible to sulphide stress cracking (SSC) in the presence of aqueous H2S environment, leading to premature failure. This project aims to study the mechanistic behaviour of TMCP steel under such low pH environment using an in-situ cathodic charging rig designed in-house. Results obtained from the various crack monitoring techniques used during the experiment will be corelated with findings obtained from the post-mortem microstructural analysis. Finally, these observations will be assessed together with those obtained using the autoclave H2S gaseous method.

 

Molten Glass Corrosion and Cobalt Superalloys

Yin Lai Chan (Research Postgraduate)

Co-supervised by Dr Mary Ryan, Dr Paul Jackson and Ms Cynthia Rodenkirchen

In collaboration with Knauf Insulation

 

 

Glass fibres for insulation are spun into fibres via a component made from cobalt superalloys. However, the molten glass fed into these components is extremely corrosive. This project aims to develop the understanding of the underlying mechanisms of corrosion through electrochemical methods.

New approaches to understanding hydrogen embrittlement in steels

Hao Pei (Research Postgraduate)

Co-supervised by Prof Martin Trusler and Prof Mary Ryan

In collaboration with Shell

 

Hydrogen derived from non-fossil sources is recognized as a viable alternative to petroleum-based fuels due to its capacity to generate power with reduced environmental impact. Consequently, maximizing the utilization of hydrogen as a substitute for fossil fuels presents a pragmatic approach to mitigating the climate change and air pollution resulting from fossil fuel emissions. Moreover, the efficacy of power generation from hydrogen is contingent upon its physical state. Research indicates that liquid hydrogen can yield greater power or electricity output compared to gaseous hydrogen under equivalent pressure and volume conditions. However, a significant challenge in the application of hydrogen lies in its storage and transportation. The permeation of hydrogen into storage materials, such as steel canisters, induces a phenomenon known as hydrogen embrittlement, compromising the structural integrity of the steel. This deterioration in mechanical properties leads to the formation of cracks, resulting in potential leakage and explosion hazards during storage and transport processes. Nonetheless, the underlying mechanisms of hydrogen embrittlement in steels remain unclear and are known to vary across different steel categories. Given that liquid hydrogen exists in cryogenic conditions (below -252.9 ℃) and possesses substantial energy release potential, investigating hydrogen embrittlement under cryogenic temperatures is essential for ensuring the safe storage and transportation of liquid hydrogen.