Abstract:The strengthening effect of fullerenes in aluminum matrix composites was investigated. The composites are produced using a two-step ball-milling technique combined with a hot rolling process. First, fullerene aggregates, where fullerene molecules initially come together to form giant particles (~200 μm in diameter) via van der Waals bonding, are shattered into smaller particles (~1 μm in diameter) by planetary milling. Second, primarily ball-milled fullerenes are dispersed in aluminum powder via attrition milling. Finally, aluminum/fullerene composite powder is consolidated by hot-rolling at 480 °C. For the composite sheet, grain refinement strengthening and dispersion hardening by fullerenes are accomplished at the same time, thereby exhibiting HV ~222 of Vickers hardness (e.g., ~740 MPa of yield strength) with only 2% (volume fraction) of fullerenes.

Key words: aluminum; fullerenes; ball-milling; powder metallurgy; composites