PhD Studentship - Understanding the influence of Oxide Dispersion strengthening on the Ductile-brittle transition temperature of EUROFER97

Funding: The studentship is open to both home and overseas applicants and will cover both the cost of tuition fee and a yearly stipend (at UKRI rate) over the course of the PhD programme.

Duration/ Funding of the project: 4 years
Industrial Sponsor: UKAEA

Supervisor: Dr Biao Cai (b.cai@bham.ac.uk)
Industrial Supervisor: John R. Echols, UKAEA

EUROFER97 (E97) is the leading candidate structural material for EU-DEMO; however, its susceptibility to thermal creep limits its upper operating temperature. Oxide dispersion strengthened (ODS) E97 promises to increase the thermal creep resistance relative to traditional E97, but early studies also reveal this ODS variant has a higher ductile-brittle transition temperature (DBTT), thus making it more susceptible to irradiation embrittlement. This PhD project aims to use in situ tensile testing with both synchrotron X-ray diffraction and scanning electron microscopy facilities, to understand the mechanism(s) driving the increase in DBTT for ODS E97. This work will inform the design of new ODS steels with lower DBTT temperatures.

The main objectives of this project are:

Objective 1: Understand the dislocation evolution in ODS E97 at temperatures around the DBTT. We will perform tensile testing of ODS E97 and non-ODS E97 steels in situ at a synchrotron X-ray diffraction facility, to examine dislocation evolution near the DBTT. We hypothesize that analysis of dislocation character (i.e., edge vs screw) and density at temperatures near the DBTT of ODS and non-ODS samples will reveal mechanisms governing the DBTT and how ODS particles affect the DBTT. We will examine ODS feature optimization based on this data.
Objective 2: Understand the influence of microstructure in ODS E97 near the crack tip at temperatures around the DBTT. We will perform tensile testing of ODS E97 and non-ODS E97 steels in situ under a scanning electron microscope (SEM), to examine microstructure-driven differences in fracture behavior. We will use electron backscatter detection (EBSD) to acquire micro-scale evolution during fracture, which will complement meso-scale synchrotron studies. We will extend ODS feature optimization to consider this micro-scale data.

Both sets of experiments (synchrotron and SEM) will use a common Deben testing rig established at the University of Birmingham. Doctor Biao Cai has developed a testing suite that allows us to carry out tensile tests at both synchrotron X-ray and microscopy facilities under a wide range of temperatures (-150 to 600 °C).

Eligibility Requirements:

An undergraduate degree in an appropriate branch of Engineering (e.g., Materials, Chemical), or the Physical Sciences (e.g., Bioscience, Physics, Chemistry), or other related disciplines with at least 2(i) honours or equivalent. 
An interest in interdisciplinary sciences and engineering, with an enthusiasm for communication. 
Evidenced mathematical ability appropriate to undergraduate discipline.
No prior knowledge of topology or topological physics is required. 
Strong supportive references and additional academic achievements (e.g., placements, research work, papers or presentations).

To apply, please click on the ‘Apply’ button above.

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