Influence of Post-heat Treatment on Friction Stir-Processed AA7075/SiC Surface Composite Properties

The effect of post-aging treatment on the evolution of microstructure and the properties of silicon carbide reinforced AA7075 surface composite manufactured by friction stir processing (FSP) were explored in this study. For this purpose, FSPed surface composites were subjected to aging treatment at 150, 180, and 210 degrees C for 8 and 16-h duration. The microstructure and properties such as microhardness and wear resistance were evaluated after aging treatment. The results showed that the grain refinement and homogenous distribution of SiC in matrix together with the precipitation strengthening enhanced the properties of FSPed surface composites. Hardness was found to be decreased at higher aging temperature and duration, due to the abnormal grain growth and the formation of stable precipitated particles in the microstructure. Surface composite samples age-treated to 180 degrees C for 8 h, and 150 degrees C for 16 h have exhibited good wear resistance and frictional characteristics. This study demonstrated that the FSP process combined with aging treatment had a significant influence on the microhardness and wear resistance of AA7075/SiC surface composite.