Deformation Behavior of La ₂ O ₃ ‐Doped Copper during Equal Channel Angular Pressing

Pure copper has a very low strength of not more than 20 MPa. Nevertheless, its mechanical properties can be enhanced by (micro)alloying, additions of strengthening particles/elements, or imparting structure modifications/grain refinement via (severe) shear strain. The presented study proposes a way of strengthening commercially pure copper by combining 5 wt% addition of La 2 O 3 particles and deformation processing. The composite is vacuum induction cast and subsequently processed by the equal channel angular pressing (ECAP) severe plastic deformation method. Single‐pass ECAP through a die with 110° angle is selected to observe the effect of La 2 O 3 addition on the development of substructure at the beginning of plastic deformation. The results show that the addition of oxide particles not only enhances the microhardness, but also efficiently supports the development of subgrains and shear bands during deformation, which finally results in an increase in the microhardness of the composite to more than double the original copper value. Although the presence of La 2 O 3 particles slightly decreases the electric conductivity, the subsequent ECAP processing provides the final composite with a conductivity of 97.9% IACS (International Annealed Copper Standard), as it promotes the alignment of the strengthening particles along the developed shear bands.