Metal-oxide nanoclusters in Fe-10%Cr alloy by ion implantation

High contents of Al+ and O+ ions were implanted sequentially into high purity Fe-10%Cr alloy thin foils at room temperature. The as-implanted foils were then studied by transmission electron microscopy (TEM) using the conventional TEM, energy dispersive X-ray (EDX), energy-filtered TEM (EFTEM) and high-resolution TEM (HRTEM) methods. In contrast to the conventional precipitate ensemble synthesis by implantation/annealing, the synthesis of clusters took place already at the implantation stage without requiring any subsequent thermal annealing in our case. The observed precipitates with diameters in the range of 3-25 nm were enriched in Al and O. The crystal lattice of precipitates corresponded to a cubic crystallographic structure of aluminium-rich oxide. The precipitate lattice alignment with the matrix was revealed for at least a part of precipitates. The early stage of nucleation outside thermal treatment is discussed in terms of point defect enhanced diffusion ensuring sufficient atomic transport to allow solute atom precipitation.