  Nanocrystalline materials are well known for their beneficial mechanical and
physical properties. However, it is of utmost importance to stabilize the
microstructure at elevated temperatures to broaden the window of application
e.g. by pinning grain boundaries through impurities or oxides. CuCo alloys,
severe plastically deformed using high-pressure torsion, were used to
investigate the evolution of oxides upon annealing. These investigations were
performed using electron microscopy, synchrotron high-energy X-ray scattering
and atom probe tomography. Monitoring the evolution of oxides by in-situ small
angle scattering investigations indicates the growth of primary oxides as well
as the formation of another species of oxide at elevated temperatures. Slightly
different coarsening can be observed in heat-treated samples, which can be
traced back to the influence of different oxide amounts. The initially
supersaturated CuCo matrix changes by the decomposition process as well as Co-
and Cu-based oxides formation and growth. It has been found that the major
number of oxides which are present after annealing, can already be found in the
starting materials.

Materials Science