Microstructure and mechanical properties of AZ91D/Si3N4 composites using squeeze casting method

The material utilized in the aerospace and automotive industries must be capable of withstanding significant loads while maintaining a minimal structural weight. In pursuit of novel lightweight materials for industrial applications, magnesium is quickly displacing aluminum-based alloys. In this study, a magnesium (AZ91D) matrix composite reinforced with nano ceramic silicon nitride (Si3N4) of varying weight proportion (2 wt%,4 wt% and 6 wt%) was synthesized using vacuum stir casting method. The microstructural study of uniform distribution of nano Si3N4 particles are revealed by an optical microscope. Micro hardness (26.8%) and tensile strength (32.12%) increased with increasing weight percentages of Si3N4 particles in a magnesium alloy matrix, whereas percentage of elongation decreased (6.52%). With an increase in weight% of Si3N4 particles in the magnesium matrix, the porosity of composites decreased (1.02%) and density of composites increased to minimum (0.06%). The corrosion characteristics were examined using B117 salt spray test. The test illustrated that an increase in percentage of reinforcement accelerates corrosion resistance (17.52%) due to induced segregation, dislocation, and micro crevice formation. Based on the results, it can be concluded that the manufactured composite can be employed in a variety of industrial applications where lighter structural materials are required.