Microstructure and Mechanical Properties Analysis of Al-6061/B4C Composites Fabricated by Conventional and Bobbin Tool Friction Stir Processing

Friction stir processing (FSP) is one of the solid-state processing technique that has gained significant attention from researchers and engineers for fabricating composites. Bobbin tool friction stir processing (BTFSP) is a novel version of conventional FSP. In the present paper, 6 mm thick plates of Al-Mg-Si (6061Al –T6) were subjected to BTFSP and CFSP using B4C reinforcement particles for comparison. The reinforcement particle distribution and mechanical properties were investigated in the fabricated composites. Agglomeration was observed in BTFSP composites. The crack formation in the BTFSP was due to the absence of forging action, which deposited the B4C particles in the crack. CFSP composites obtained uniform distribution of the B4C particles at the top surface. The tilt of the tool in CFSP helped in effective forging action by the shoulder at the trailing edge. Micro-hardness results indicated improved hardness at the top surface for both the processed composites.