Investigation on microstructural, mechanical and damping properties of SiC/TiO2, SiC/Li4Ti5O12 reinforced Al matrix

Abstract

The material response and composite functionality are controlled by matrix-ceramic particulate interface. It is unfortunate that silicon carbide (SiC) dispersoid exhibit inferior wettability in molten aluminium matrix. Herein, we effectively synthesize titanium oxide (TiO2) and nanocrystalline lithium titanate (Li4Ti5O12 abbreviated as LTO) spinel coated core-shell structures of SiC via novel hydrothermal technique for enhancing the dispersoids wettability. Various characterization techniques like field emission scanning electron microscope (FE-SEM), energy-dispersive X-ray spectroscopy (EDX), transmission electron microscope (TEM) were employed for thorough analysis of core-shell structures. Furthermore, the aluminium metal matrix composites (AMMCs) were fabricated by incorporating pristine SiC, TiO2 encapsulated SiC and Li4Ti5O12 encapsulated SiC, respectively via stir casting process. Additionally, friction stir process was carried out on the composite castings to obtained refined grains and adequate dispersion of reinforced particles which can further create opportunity to study the effect of refined grains on damping and mechanical (tensile and hardness) properties. Microstructural analysis was conducted through electron back scattered diffraction (EBSD). The composites were examined for their thermal and mechanical cyclic damping performance in the temperature range from −100 to 400 °C. Finally, the improved material properties can be attributed to the customized SiC particles with reduced agglomeration, stabilization and good dispersion with the aluminium matrix.