The aim is to design and manufacture the next generation metastable alloys by an additive manufacturing approach, i.e. by electron beam melting, so as to yield simultaneously (ultra-) high levels of mechanical strength and ductility not achievable by conventional metallurgical approaches. The key to achieve this goal resides in the presence of metastable phases (normally <20 vol.%) within very fine complex microstructures. The metastable phase transforms progressively under mechanical loading (either during component manufacturing or in-service) into a harder stable phase and/or is susceptible to the continuous formation of a high density of twin defects. This is the case of the metastable gamma-iron phase in high-performance automotive steels such as TRanformation Induced Plasticity (TRIP) or Twinning Induced Plasticity (TWIP) steels, or the beta-titanium phase in aerospace titanium alloys. Despite the potential material’s benefits, the conventional manufacturing processes of bulk quantities of material do not provide the opportunity to tailor the stability of those phases adequately. Besides that, the metastable phase behaviour tailored for low strain rates does not correspond to its response under the faster strain rates characteristic of industrial forming processes.
In this project, you will manufacture instead the next generation metastable alloys using electron beam melting (EBM), based on a systematic alloy design using thermodynamic and ab initio calculations, coupled with density functional theory simulations. EBM is a (near-)net shape technology based on the sequential deposition of a pre-alloyed or pre-mixed powder on a selected substrate, and the subsequent powder melting using a high power electron beam following a computer-controlled path. Its layer-by-layer approach permits to control and vary the microstructure as is being built. The EBM process is also characterised by fast cooling rates from the melt, therefore having the potential of retaining significant amounts of high-temperature phases in a metastable state in the alloy structure.
You will first optimise the EBM process parameters to produce standard metastable alloys, and compare their microstructure and mechanical performance with those currently in the market. This will constitute the foundation to design and produce new alloy chemistries and EBMed microstructures, ultimately producing hierarchical heterogeneous microstructures with controlled phase metastability for optimal local TRIP/TWIP effect. Those novel microstructures will be characterised by complementary electron microscopy techniques across length scales, and their mechanics tested in situ in synchrotron X-ray experiments under deformation.
This project is part of a collaboration between the University of Manchester and the Singapore Institute of Manufacturing Technology (A*STAR SIMTech). The first part of the project will be at the University of Manchester’s Materials Performance Centre, where you will complete the project-relevant training courses and characterise conventional EBMed alloys. You will then be based at SIMTech in Singapore for two years where you will design and manufacture new metastable alloys. You will return to Manchester to focus on the mechanics of the EBMed microstructures and also to write up your thesis.
Applicants must have obtained, or be about to obtain, at least an upper second class honours degree or the equivalent qualification gained outside the UK, in an appropriate area of science, engineering or technology.
UK applicants interested in this project should make direct contact with the Principal Supervisor to arrange to discuss the project further as soon as possible. International applicants (including EU nationals) must ensure they meet the academic eligibility criteria (including English Language) as outlined before contacting potential supervisors to express an interest in their project. Eligibility can be checked via the University Country Specific information page (https://www.manchester.ac.uk/study/international/country-specific-information/).
Some restrictions apply to applicants from certain Asian countries. In general, students from Europe, the Americas, Africa, Australia, New Zealand, Korea and Japan are eligible to apply for the programme. Unfortunately, we cannot accept applications from south-east Asian countries such as Singapore, China and Malaysia.
Following the review of your qualifications and with support from potential supervisor(s), you will be informed whether you can submit a formal online application.
Equality, diversity and inclusion is fundamental to the success of The University of Manchester and is at the heart of all of our activities. The full Equality, diversity and inclusion statement can be found on the website https://www.bmh.manchester.ac.uk/study/research/apply/equality-diversity-inclusion/
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