Friction Stir Processing (FSP) of Multiwall Carbon Nanotubes and Boron Carbide Reinforced Aluminum Alloy (Al 5083) Composites

Abstract

Friction Stir Processing (FSP) is a novel solid-state processing technique for fabrication of high strength surface composites. In present study, FSP was used to compare the cold formability of individually reinforced, hybrid and reference FSP samples of aluminum alloy Al5083. A plate of alloy containing MultiWall Carbon NanoTubes (MWCNTs) and boron carbide particles (B4C) was processed by FSP and characterized. FSP composite containing MWCNTs was found to fracture during the bend-ductility test, while boron carbide particles reinforced FSP composites had superior cold bending formability along with the reference FSP sample. Cracking was also observed in hybrid FSP composite samples in lesser extent as compared to individually reinforced MWCNTs FSP composite. Possible cause of failure was identified as clustering of MWCNTs and weak interfacial bonding with the aluminum alloy matrix. Detailed metallographic and mechanical testing investigations revealed that the distribution of reinforcement at nanoscale and single pass processing played a vital role in generating defects and sinking of reinforcement particles in Al5083 matrix.