Characterization of dispersion strengthened copper with 3wt%Al2O3 by mechanical alloying

• Published in: Science of sintering Vol. 36; no. 3; pp. 205 - 211
• Main Authors: Rajkovic, V, Eric, O, Bozic, D, Mitkov, M, Romhanji, E
• Format: Journal Article
• Language: English
• Published: International Institute for the Science of Sintering, Beograd 01.09.2004
• Subjects: dispersion strengthened copper; mechanical alloying; micro hardness
• ISSN: 0350-820X; 1820-7413
• DOI: 10.2298/SOS0403205R

The copper matrix has been dispersion strengthened with 3wt. %Al2O3 by mechanical alloying. Commercial alumina powder with an average particle size of 0.75 mum was used for alloying. The mechanical alloying process was performed in a planetary ball mill up to 20h in air. After milling all powders were treated in 112 at 400DGC for 1h, and finally hot pressing was used for compaction (800DGC, 3h, Ar). Structure observations revealed a lamellar structure (Al2O3 particles largely restricted to interlamellar planes between adjacent copper lamellae) accompanied also by structure refinement. These structural changes were mostly completed in the early stage of milling, and retained after compaction. Micro hardness was found to progressively increase with milling time. So, after 5h of milling the micro hardness of the Cu+3twt%Al2O3 compact was 1540MPa, i.e. 2.5 times greater than for the as-received electrolytic copper powder (638MPa) compacted under identical conditions, while after 20h of milling it was 2370 MPa. However, after exposing the tested compact at 800DGC up to 5h, the achieved hardening effect vanished.