Effect of CNTs on precipitation hardening behavior of CNT/Al–Cu composites Original Research Article

The precipitation hardening behavior of CNT/Al–Cu composites was investigated by characterization of microstructure and mechanical properties after aging heat treatment. It was found that CNTs accelerated the precipitation hardening behavior of CNT/Al–Cu composites due to the generation of excess dislocations. The CNT/Al–Cu composites; after aging heat treatment, show significant increase of yield and ultimate tensile strength compared to those values for the Al–Cu matrix; the composites also show an increase rate similar to that of CNT/Al–Cu composites without aging heat treatment. It was thought that the CNT/Al–Cu composites were strengthened by both the load transfer from the Al–Cu matrix to the CNTs and by precipitation hardening of the Al–Cu matrix.