Almost all materials we use in our civilisation are crystals, and the things that make crystals interesting are their defects. One of the most important crystals defects are dislocations, and they are key to understanding how materials deform plastically. In some materials, for examples the tungsten used in fusion reactors, certain types of dislocations can behave in unusual ways, by having low mobility making the materials much more brittle. The explanation of this unusual behaviour probably lies in the detailed atomic arrangement at the core of the dislocation, but a full 3D characterisation of such defects has not before been possible. Here we make use of a novel “optical sectioning” procedure we have developed in our laboratory to determine the structure of dislocations at atomic resolution in 3D using electron microscopy. Using this approach to relate atomic structure to materials properties allows the rational design of alloys to improve the ductility of important structural materials.
This project would suit someone who enjoys challenging experiments but also wants to experience the excitement of seeing atoms in materials. In addition to hands on experiments, the project will involve data processing using scripting in software packages such as Matlab.