Surface property enhancement of AA 6061-T6 alloy using friction stir processing with Fe-based chip and Zircoat powder

Friction stir processing (FSP) is a popular, easy-to-use and affordable solid-phase processing technique for changing the surface characteristics of materials. Aluminum metal matrix composites (AMMCs) are employed in a variety of engineering applications due to their increased stiffness, wear resistance and specific strength. Surface AMMCs are developed on AA 6061-T6 aluminum (Al) alloy using FSP for improving the surface characteristics, including grain refinement. In the present work, AMMCs were fabricated by dispersing Fe-based chips and Zircoat-M powder through the FSP route. The optical micrographs showed a uniform distribution of reinforcement in the base matrix. The maximum surface roughness of 6.18 µm was observed in the base matrix after FSP with an Fe-based chip, compared to 4.24 µm in the FSP of the base matrix without any reinforcement. By dispersing Fe-based chip and Zircoat-M together, a hardness of 294 HV could be achieved against 77 HV for the base Al alloy. The yield strength of this hybrid composite was 254 MPa compared to 212 MPa of the base Al alloy. The hybrid composite also provided low wear mass loss and wear depth.