Development of AA5052/TiO2/SiC hybrid surface composites using upward material flow through multipass friction stir processing

Abstract

The present study employed upward material flow during friction stir processing (FSP) to develop AA5052/TiO2/SiC hybrid surface composites rather than the downward material flow that is conventionally used. The upward material flow was generated with the help of a right-handed threaded pin tool rotating in a clockwise direction causing plastically deformed material to flow in the three-dimensional region of the stir zone. The result showed that the upward material flow pattern and multipass significantly improved the properties of composites. Substantial grain refinement was obtained after each successive pass due to the uniform distribution of fragmented reinforcement particles and intense plastic deformation during FSP. The maximum microhardness of 88.73 HV and ultimate tensile strength of 220.8 MPa were obtained after the fourth FSP pass in developed hybrid surface composites. Additionally, the tribological analysis showed that wear resistance increased with the number of passes.