Properties and spot welding behaviour of copper-alumina composites through ball milling and mechanical alloying

This paper aims to study effect of compaction pressure on properties and spot welding behaviour of Cu-10 wt%Al2O3 composite prepared via two powder mixing methods, i.e. ball milling and mechanical alloying. The composite is either mixed in a low energy ball mill or by mechanical alloying in a high energy planetary mill for 45 min. The mixture was then compacted at 100, 200, 300 and 400 MPa and sintered in argon atmosphere at 950 degrees C for 1 h. Results showed that composite prepared via mechanical alloying has better hardness and lower electrical conductivity and density than its counterpart due to powder refinement. Higher compaction pressure increases the hardness, electrical conductivity and density of the composite prepared by both methods. The mechanical alloyed composite compacted at higher pressure imparts material flow during spot welding operation. Thus, spot weld with higher strength was obtained. (C) 2007 Elsevier Ltd. All rights reserved.