Effect of SiC on the Microstructure and Properties of SiC/Al6061 Composites Fabricated by Additive Friction Stir Deposition

In this study, SiC particle-reinforced aluminum matrix composites were fabricated by additive friction stir deposition (AFSD). The effect of SiC particle fraction on the microstructure and mechanical properties was systematically investigated using scanning electron microscopy (SEM), electron backscattering diffraction (EBSD) and tensile testing. The results showed that grain refinement is most significant when the SiC content is 15%, and the microhardness of the composite reaches a significantly higher value of 83.75 HV. This enhancement is primarily attributed to the pinning effect of SiC particles on grain boundary migration and the promotion of dynamic recrystallization during the AFSD process. However, the addition of 15% SiC in the composite caused agglomeration, which degrades the plastic deformation capacity and leads to a reduction in elongation.