The project will obtain fundamental knowledge about quasicrystal formation and growth from supersaturated solid solution. Two material systems are selected: Al-Mn-Si-(Cr) and Al-Mg-Cu-(Ag). The novel approach implies solving atomic structure of quasicrystal at selected growth stages in close reference to the Al host lattice. State-of-the-art analysis methods (Transmission Electron Microscopy and Atom Probe Tomography) will be used to image the smallest quasicrystal building blocks (molecular units), their subsequent aggregates, and the final quasicrystal phases after selected heat treatments. The techniques offer sufficient resolution that atomic models of the small aggregates can be made at each stage, together with the surrounding host. The project also has a novelty aspect related to use of Scanning Precession Electron Diffraction on small quasicrystal precipitates in a host lattice. Ab-initio quantum mechanical calculations will be used to test the structure models of the different stages. These calculations will be based on a novel on-the-fly machine learning force field methodology. The lattice kinetic Monte Carlo technique will be applied to model the time evolution of the QC growth. Results will be compiled into an experimentally verified set of growth rules for quasicrystals, a final sub-goal for the project. The most critical milestone for the project is the final validation of the selected materials' suitability for the study in terms of the kinetics of the quasicrystal formation.
Project leader: Sigmund Jarle Andersen
Category: Teknisk-industrielle institutter
Institution: SINTEF AS