Microstructure and mechanical properties of wear-resistant SiCp/Al composite layers on 6061 aluminum alloy fabricated by additive friction stir deposition

Due to the excellent wear properties of the SiC particles reinforced aluminum matrix composites(SiC_p/Al) and its good compatibility with the aluminum alloy substrate, the fabrication of a SiC_p/Al layer is an effective way to improve the surface wear resistance of aluminum alloys. In this study, the microstructure and mechanical properties of a 20 vol% SiC_p+ZL101 composite deposition layer on the surface of 6061-T6 fabricated by the additive friction stir deposition (AFSD) process. The results show that plastic deformation leads to approximately 97 % grain refinement in the deposition layer compared to the rod material (RM). SiC_p are fragmented and refined, with an average size reduction from 4.54 μm × 2.80 μm (RM) to 2.40 μm × 1.52 μm, achieving a uniform distribution. The tensile strength of deposition layer reaches 300 MPa, a 47 % improvement over the RM. A defect-free metallurgical bond is formed at the interface, and fine-grained regions at the interface enhance crack resistance, with a shear strength of 177 MPa. Both RM and the deposition layer exhibited characteristics of abrasive wear and oxidative wear. Compared to the RM, the deposition layer showed a ∼10 % reduction in wear rate. The tensile strength of the deposit layer has been enhanced without compromising wear resistance. This study provides insights for using AFSD in fabricating wear-resistant surface layers or surface-modified components.