Effect of CNTs on precipitation hardening behavior of CNT/Al-Cu composites

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 GMT/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. (C) 2012 Elsevier Ltd. All rights reserved.