Abstract
The study compares microstructural characteristics of Cu-CuAl₂O₄ and Cu-MgO composite materials where the secondary oxide phase represents 3 % of volume. The effect of both dispersoid types on preservation of the initial nanostructure of copper powder particles after their consolidation is analysed. Selection of the secondary phase is one of the most important factors influencing the stability at the powder interface. Fine and uniformly distributed CuAl₂O₄ particles with a good bonding to the Cu matrix fulfil their main role -- they limit the grain growth and maintain its nanometric size during the entire thermo-deformation material treatment. Due to the weak Cu/MgO interface during thermal loading conditions, Cu matrix is not sufficiently controlled by MgO. MgO agglomerates into coarser particles of the size of above 50 nm. The large MgO particles do not strengthen grain boundaries and negatively influence all microstructural parameters investigated in our study.

Key words
nanocrystalline copper, composite material, dispersoid, microstructure, interface stability

Full text not available