Effects of copper and Al2O3 particles on characteristics of Cu–Al2O3 composites

• Published in: Materials in engineering 2010-04, Vol.31 (4), p.1962-1970
• Main Authors: Rajkovic, Viseslava, Bozic, Dusan, Jovanovic, Milan T.
• Format: Article
• Language: English
• ISSN: 0261-3069
• DOI: 10.1016/j.matdes.2009.10.037

High-energy milling was used to produce Cu-Al2O3 composites. An inert gas-atomised prealloyed copper powder containing 2 wt% Al and a mixture of different sized electrolytic copper powders with 4 wt% commercial Al2O3 powders served as starting materials. Milling of prealloyed copper powders promotes formation of nano-sized Al2O3 particles by internal oxidation with oxygen from air. Hot-pressed compacts of composites obtained from 5 and 20 h milled powders were subjected to high-temperature exposure in argon at 800 C for 1 and 5 h. Characterisation was performed by optical microscopy and SEM, XRD, microhardness, and density and electrical conductivity measurements. Due to the nano-sized Al2O3 particles, microhardness and thermal stability of composites processed from milled prealloyed powders were higher than the corresponding properties of composites processed from the milled powder mixtures. The results are discussed in terms of the effects of different sizes of starting copper powders and Al2O3 particles on the structure, strengthening of the copper matrix, thermal stability and electrical conductivity of Cu-Al2O3 composites.