Wear characteristic of aluminum-based composites containing multi-walled carbon nanotubes

This study reports mechanical properties and wear characteristics of ultrafine-grained aluminum and aluminum-based composites, where well dispersed and aluminum atom-infiltrated multi-wall carbon nanotubes (MWCNTs) form a strong interface with the matrix by mechanical interlocking. Wear characteristics, varied according to the grain size and the MWCNT volume, are evaluated under the varied combinations of an applied load and a sliding speed. As grain size is reduced and the MWCNT volume increases, strength and wear resistance are significantly enhanced and the coefficient of friction is extremely reduced. The ultrafine-grained composite containing 4.5 vol. % of MWCNTs exhibits more than 600 MPa in yield stress and less than 0.1 in the coefficient of friction. The coefficient of friction and the wear rate increases with increasing the load, while they are reduced with increasing the sliding speed. The wear mechanism is considered to be micro-ploughing and delamination, irrespective of the MWCNT volume, applied load and sliding speed. This study demonstrates that MWCNTs are effective reinforcement for enhancing wear characteristics as well as mechanical properties.