Microstructural and mechanical properties of CDA/SiC reinforced Al7075 hybrid composite synthesized by stir-casting

In this study, a hybrid metal matrix composite reinforced with a combination of ceramic (SiC) and agro-waste (CDA) particles is developed using stir-casting technique coupled with an ultrasonic transducer. Developed samples were thoroughly examined on microstructural aspects using Optical Microscopy (OM), Field Emission Scanning Electron Microscopy (FESEM) with elemental mapping, and X-ray diffraction (XRD) techniques, which revealed reinforcement particle presence and their homogeneous dispersion throughout the matrix. The synthesized samples were examined for their physical and mechanical characteristics, revealing that the porosity of all samples was less than 2%. The composite containing an equal weight percentage (2.5% CDA and 2.5% SiC) of reinforcement exhibits a 32.72% increase in hardness and a 46.48% increase in tensile strength compared to the as-cast alloy. The FESEM analysis of tensile fractured surfaces revealed the presence of ductile dimples, river lines, cleavage features, particle cracks, and pull-out fractures indicating different mode of fractures. The study demonstrates that the Al7075-CDA/SiC hybrid composite offers superior mechanical performance compared to conventional Al7075, making it a promising material for applications in automobile piston, brake caliper and wheels.