Developing high-performance aluminum matrix composites with directionally aligned carbon nanotubes by combining friction stir processing and subsequent rolling

A route combining friction stir processing and subsequent rolling processing was established to fabricate 1.5–4.5 vol.% carbon nanotube (CNT)-reinforced 2009Al composites. Microstructural observations indicated that CNTs were individually dispersed and directionally aligned in the aluminum matrix of the CNT/2009Al composites. The tube structure of the CNTs was retained and the CNT–Al interface was bonded without pores. As a result, great increases in yield strength, ultimate tensile strength, and Young’s modulus were achieved when a higher concentration of CNTs was incorporated. Moreover, the composites exhibited good ductility. In particular, 3 vol.% CNT/2009Al composite exhibited an ultimate tensile strength of 600 MPa and elongation of 10%, much higher strength–ductility than the corresponding values for CNT/Al composites fabricated by other processes.