Microstructural and tribological properties of Al5083 based surface hybrid composite produced by friction stir processing

In this study, a self-lubricating and wear resistant surface hybrid Al-base composite reinforced with a mixture of SiC and MoS2 particles has been successfully fabricated by Friction Stir Processing (FSP). Microstructure, hardness and dry sliding wear behavior of the hybrid composite have been investigated and compared with those of base metal and Al/SiC and Al/MoS2 composites. Microstructural analyses of the hybrid composite showed a uniform distribution of reinforcing particles inside the processed zone and a good bonding between surface processed layer and base material. The tribological studies showed that surface hybrid composite has the highest wear resistance in comparison to other samples. Moreover, dominant wear mechanisms operating in dry sliding conditions of samples were studied. The results indicated that light delamination and light abrasion mechanisms operated simultaneously during wear of the hybrid composite. The wear mechanisms confirmed that the formation of hybrid composite on the surface could significantly reduce the wear damages and improve the wear resistance of the alloy. (C) 2012 Elsevier B.V. All rights reserved.