Investigation of Nano-Al2O3 and Micro-coconut Shell Ash (CSA) Reinforced AA7075 Hybrid Metal–Matrix Composite Using Two-Stage Stir Casting.

The present work is focused on the influences of reinforced particles on mechanical, microstructural, and tribological performances of AA7075 hybrid metal–matrix composites (HMMCs). Al2O3 and coconut shell ash (CSA) were reinforced using two-stage stir casting by varying the wt% (0–5) of reinforcement. Microstructural analysis and various phase identifications were examined with the help of scanning electron microscope (SEM) equipped with EDX and optical microscope. Various mechanical testing such as tensile, hardness, 3-point bend test, and tribological behaviors were carried out to know the HMMCs properties. Microstructural images revealed a homogeneous distribution of reinforced particles in the metal–matrix and EDX confirmed the presence of dispersed reinforcements (Al2O3 and CSA) in the HMMCs. It was seen that mechanical properties and tribological behavior have been increased after addition of Al2O3 and CSA reinforced particles whereas slightly decreased in impact strength. Transgranular cleavage facets, micro-void coalescence, dimples, and crack were shown in SEM images of fractured specimens during impact and tensile testing. [ABSTRACT FROM AUTHOR]