Synthesis and characteristics of precipitation hardened Cu-Cr alloy and multiply hardened Cu-Cr-Al2O3 nanocomposite obtained using powder metallurgy techniques

The hardening of copper alloy by using powder metallurgy techniques and analysis of its effects on the strength of obtained material are discussed. Prealloyed Cu-0.5 wt.% Cr powder and mechanically alloyed Cu-0.5 wt.% Cr-3 wt.% Al2O3 powder were consolidated by means of hot pressing. Optical microscopy, scanning electron microscopy and transmission electron microscopy were used for microstructure characterization of compacts. Hardness and electrical conductivity of both compacts were compared. High strengthening of the Cu-Cr compacts is achieved by aging as a consequence of the influence of precipitation particles rich in chromium. In the case of the Cu-Cr-Al2O3 composite it is a consequence of precipitation of particles rich in chromium and the presence of Al2O3 dispersoid nanopartidies