Investigation on the Effect of Al ₂ O ₃ and B ₄ C Ceramic Particles on Mechanical Properties of AA7075 Metal Matrix Composites

The present research work aims to investigate the mechanical properties of AA7075 hybrid composite reinforced with aluminum oxide (Al₂O₃) and boron carbide (B₄C). In this research, fabrication of composites is completed in two stages: In the first stage, the Al₂O₃ composites were fabricated and mechanical properties were tested. The reinforcement weight percentage (wt%) of Al₂O₃ having the maximum value of tensile strength, hardness, and flexural strength and impact energy is selected and reinforced with a different weight percentage of B₄C to investigate the effect. The internal structure of the composite is observed using a scanning electron microscope to analyze the fracture mechanism. The tensile strength, flexural strength, and hardness of the composites increased with an increase in the weight percentage of reinforcement. The tensile strength of the composites increased to 279 MPa, flexural strength increased to 340 N/mm², and elongation percentage of the composites decreased up to 4.6% by reinforcement of 12 wt% Al₂O₃ and 2 wt% B₄C. The impact energy of the composites decreased up to 4.4 J while the hardness of the composites increased to 143 BHN with 12 wt% Al₂O₃ and 3 wt% B₄C. Scanning electron microscopy (SEM) showed uniform distribution of reinforcement particles and grain refinement of the matrix.