Mechanical and microstructural analysis of AA7075/B4C/ZrO2 hybrid composite

Abstract The primary objective of this study is to examine the impact of incorporating boron carbide (B 4 C) and zirconium oxide (ZrO₂) on the mechanical characteristics of AA7075 composites. Different weight fractions of B 4 C and ZrO₂ were used to fabricate the composites via powder metallurgy, and mechanical tests, including hardness and compression strength, were performed to assess their properties. Microstructural analysis was conducted to evaluate the dispersion and interfacial bonding of the reinforcements within the matrix. The results revealed a significant enhancement in mechanical properties, with a maximum compression strength of 252 MPa, representing a 165% increase compared to the unreinforced alloy. This improvement is attributed to key strengthening mechanisms, including strain hardening induced by dislocation-particle interactions, grain boundary strengthening through refinement, effective load transfer between the matrix and reinforcements, and Zener pinning that stabilized the microstructure during sintering. The addition of ZrO₂ as a secondary reinforcement further enhanced these effects, leading to optimized mechanical performance. These findings provide valuable insights into the design and development of advanced hybrid composites for industrial applications.