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Postgraduate research project

Designing a simple section method to acquire large volume 3D microstructure of additively manufactured light alloys

Funding
Competition funded View fees and funding
Type of degree
Doctor of Philosophy
Entry requirements
2:1 honours degree
View full entry requirements
Faculty graduate school
Faculty of Engineering and Physical Sciences
Closing date

About the project

The microstructure evolution of alloys during additive manufacturing is expected to be complex and some feature sizes could range from tens of nanometers up to several hundreds of microns that need to be mapped in 3D. 2D microstructure information is insufficient to understand and develop models of the fundamental mechanisms that determine the properties of the alloys. Thus a combination of EBSD and Focused Ion Beam (FIB) milling is conventionally used to access 3D information. However, long milling times of Ga source FIBs have limited analysis volumes on the tens of micron dimensions, which cannot provide the required microstructure information. 

 

Even the most advanced Laser Plasma FIB only allows sample analysis just exceeding spatial dimensions of 1000 × 1000 × 500 µm³ with regular equipment time, which cannot provide typical microstructure information with grain size over 100 µm. Thus, developing a novel section method to acquire a large volume of 3D information using short equipment time with low cost is indispensable to analyse complex microstructures.  Our group has recently published several in-situ microstructure characterisation works in high quality journal papers [1-5]. 

These research outcomes enabled our group to win a UKRI Future Leaders Fellowship. Our most recent work published in Acta Materialia used this section method to obtain a large volume of microstructure information and disclosed new insight into deformation mechanisms in alloys [5].

This project aims to fully explore the complex and unique microstructure of additively manufactured magnesium and aluminium alloys.

Three specific objectives are:

  1. Design novel etching/ polishing strategies to uniformly etch/remove sample surface, and control surface reduction rate and depth.
  2. Employ electron microscopy techniques to obtain data after serial sectioning and reconstruct the data in 3D using open-source software.
  3. Develop scripts to process the microstructure data efficiently and extract the key information automatically.
  4. Correlate the microstructure information with the mechanical property testing results

Besides standard PhD training, this project will provide training experience including 1) solid training in light alloy metallurgy, advanced electron microscope characterisation, large dataset processing and corrosion science, 2) collaboration opportunities with our industry partners and academic collaborators; 3) Personal career development training courses funded by supervisor’s fellowship project, (4) PGR demonstrator experience, this will allow you to earn extra £3,000-4,000 salary per year and also could be used to support you for applying for Associate Fellowship awarded by AdvanceHE.


References:
[1] Twin recrystallization mechanisms and exceptional contribution to texture evolution during annealing in a magnesium alloy (2017). 
[2] Individual effect of recrystallisation nucleation sites on texture weakening in a magnesium alloy: Part 1- double twins (2017) 
[3] Individual effect of recrystallisation nucleation sites on texture weakening in a magnesium alloy: Part 2- shear bands (2018)  
[4] Basal slip mediated tension twin variant selection in magnesium WE43 alloy (2019)
[5] Three-dimensional study of grain scale tensile twinning activity in magnesium: A combination of microstructure characterization and mechanical modeling (2023)
 

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