Fabrication of Al5083 surface hybrid nanocomposite reinforced by CNTs and Al ₂ O ₃ nanoparticles using friction stir processing

Abstract

In the present study, friction stir processing was adopted for surface treatment of Al5083 by incorporation of CNT and Al 2 O 3 nanoparticles. Microstructural, mechanical and tribological properties of the surface of Al5083/CNT, Al5083/Al 2 O 3 and hybrid Al5083/CNT/Al 2 O 3 nanocomposite were investigated and compared. The friction stir processing yielded a nearly uniform dispersion of CNTs and Al 2 O 3 nanoparticles, irrespective of nanoparticle reinforcements and their weight fraction. Microstructural observations revealed that Al 2 O 3 nanoparticles have dispersed in different zones including intra-grain and grain boundary zones while, CNTs are pinned into grain boundaries during friction stir processing. From mechanical point of view, hybridization of CNT/Al 2 O 3 enhances the hardness (126 HV at stirred zone), strength (UTS of ∼487 MPa) and also wear resistance of Al5083/CNT/Al 2 O 3 nanocomposites. The enhancement is attributed to the presence and combination of features of both CNT and Al 2 O 3 nanoparticles which are different in nature; one spherical oxide and one nanotube.