In-Situ Study of Turbostratic Disorder in High-Purity Ti3AlC2 and Ti2AlC by PDF analysis

This proposal seeks to investigate the turbostratic disorder in high-purity Ti3AlC2 and Ti2AlC MAX-phase powders using Pair Distribution Function (PDF) analysis. Turbostratic disorder is the rotational misalignment between crystallographic layers, and produces characteristic asymmetric broadening of diffraction peaks. This can complicate conventional diffraction techniques such as Rietveld refinement. MAX-phases exhibit significant turbostratic disorder, impacting their mechanical properties and suitability for nuclear applications. This study builds upon previous neutron diffraction experiments at Engin-X and Electron Backscatter diffraction (EBSD), which confirmed the presence of turbostratic disorder features in the diffraction data. However, limitations of the Rietveld refinement method suggest that PDF analysis may be superior in isolating and characterising the turbostratic disorder. The proposed beamtime calls for in situ neutron diffraction at a range of temperatures (25-1000°C) to isolate and analyse features identifying turbostratic broadening. This will provide crucial experimental data against which models of diffraction and mechanical behaviour may be tested. These results could therefore enhance data fitting techniques for a range of turbostratically-disordered materials.