Effect of tool shoulder geometry on fabrication of Al/Al₂O₃ surface nano composite by friction stir processing

Abstract

Friction stir processing (FSP) is used to fabricate nano Al₂O₃ reinforced 6061 Al surface nanocomposite with the aim to get defect-free surface nanocomposite with single-pass FSP. In this research work, the impact of tool shoulder geometry, rotational and traverse speeds of the tool on the microstructure, material flow, and microhardness of the fabricated surface nanocomposite was studied. At a particular combination of the process parameters, a uniform mixture of the aluminum matrix material and Al₂O₃ nano reinforcement particles were mixed well and exhibited good mechanical and hardness properties. The fabricated surface nanocomposite showed higher microhardness than the as- received 6061 Al alloy. The average microhardness of the composite was achieved as ∼132 Hv with 24 mm shoulder diameter of the tool. The results show that FSP is an effective way to produce Al/Al₂O₃ surface nanocomposite with excellent microstructural and mechanical properties.

Keywords:

• Friction stir processing
• tool geometry
• process parameters
• microstructure
• material flow
• mechanical properties

Acknowledgements

The authors would like to thank the authorities of National Institute of Technology (NIT), Warangal, INDIA for providing the facilities to carry out this work.