Microstructure and Tensile Behavior of Friction Stir Processed AA6061/Al3Fe Cast Aluminum Matrix Composites
By Sathiskumar Ramasamy (Coimbatore Institute of Technology), Balakrishnan M (Nehru Institute of Engineering and Technology), Murugan N (PSG College of Technology), Palanivel R (University of Johannesburg)

Aluminum matrix composites (AMCs) meet the requirement for light weight materials with high specific strength. AMCs possess several other covetable properties such as improved wear resistance, limited expansion to thermal heating and stability at elevated temperature. In this research, Al / (0 – 15 wt. %) Al3Fe AMCs were prepared by adding pure iron powder to molten aluminum and subjected to Friction Stir Processing (FSP). Friction stir processing (FSP) has emerged as an effective secondary processing technique to improve the microstructure and properties of AMCs. The microstructural changes before and after FSP were studied using OM, SEM, EBSD and TEM. Cast composites exhibited coarse grains, segregation, pores and sharp-edged particles. The distribution of particles was rearranged into a homogeneous distribution after FSP. Casting defects such as pores were eliminated. The sharp edges of Al3Fe particles were removed and rounded into near spherical shape. The grain size reduced remarkably due to severe plastic deformation and the pinning effect of reinforced particles. The density of dislocations increased considerably after FSP. The microstructural changes resulted in an improvement of tensile strength and ductility.