Effect of Microstructure on Mechanical Behaviors of Al6061 Metal Matrix Composite Reinforced with Silicon Nitride (Si3N4) and Silicon Carbide (SiC) Micro Particles

The urge to obtain an excellent combination of properties in one material causes the development of new material. Present research work coincides with this mind set. The research work has involved the development of aluminum alloy hybrid composite using Al6061 as matrix and silicon nitride (Si3N4) and silicon carbide (SiC) as hybrid reinforcement particles by dual step stir casting method. Micron SiC and submicron Si3N4 particles in varying weight proportion and percentage have been introduced into matrix for composite fabrication. Four hybrid composites along with the base alloy were casted. The microstructures of the composites examined under optical and field emission scanning electron microscope (FESEM) exhibited a homogeneous and uniform distribution of hybrid reinforcements with no significant porosity. X-ray diffraction (XRD) demonstrates that SiC and Si3N4 particles are thermodynamically stable during the processing and no undesirable phases are formed. Energy dispersive X-ray spectroscopy (EDX) was also done to confirm the elemental presence. All hybrid compositions reported an increase in hardness and ultimate tensile strength (UTS). Maximum increase in hardness was 54.64% while maximum UTS was 41.78%. Two out of four hybrid composition show a significant rise in ductility. Heat-treatment enhanced the hardness and tensile strength. The fractured surface of the tensile test was examined under FESEM to know the fracture mechanism.