Supervisor: Peter Brommer

Student: Geraldine Anis

The extraordinary strength of superalloys is derived from precipitates – nanoscale inclusions embedded in the material. These strengthen the material by hindering the motion of dislocations, which are responsible for material deformation. This project explores the effect of variations of precipitate size and shape on the properties of the material. A better understanding of precipitates will lead to rational criteria for the design of new high strength alloys that would increase the efficiency of turbine products and new engine designs.

In this project, the effects of variations in precipitate properties in precipitation-hardened alloys will be studied using a hierarchy of simulation methods, from atomistic Molecular Dynamics to Discrete Dislocation Dynamics or Crystal Plasticity, where smaller scales will inform larger scale simulations. Potentially, computational homogenisation approaches will be employed. At the end of the project, we understand how variations in precipitate morphology impact the properties of the material, thus quantifying the sensitivity of macroscopic quantities on nanoscale properties (e.g., precipitation shape).

This project will be undertaken in collaboration with our international partners at FAU Erlangen-Nürnberg (Prof. Erik Bitzek) and Universität Stuttgart (Prof. Siegfried Schmauder).

The background image (by H. Lyu, E. Bitzek, FAU Erlangen-Nürnberg) shows a pair of dislocations (lines of red atoms) approaching irregularly shaped precipitates (dark grey). The inset image on the left shows pairs of dislocations crossing precipitates in different sizes. On the right, a pair of dislocations is shown crossing through precipitates. Inset images adapted from Kirchmayer, Lyu, et al., Adv. Eng. Mater 22: 2000149.