Effect of B₄C_p Volume Fraction on Microstructure and Properties of B₄C_p/SiC_p Hybrid Reinforced 2000 Series Aluminum Matrix Composites

Micron boron carbide particle (B₄C_p) and 2 vol % nano silicon carbide particle (SiC_p) reinforced 2000 series aluminum matrix composites (AMCs) with different volume fractions of B₄C_p (10, 15, and 20 vol %) were fabricated by powder metallurgy. In this study, the microstructure of B₄C_p/SiC_p reinforced 2000 series AMCs was analyzed using an optical microscopy (OM), scanning electron microscopy (SEM), and energy dispersive spectroscopy (EDS). Additionally, X-ray diffraction (XRD) analysis was adopted to identify inter-metallic phases that were formed during the heat treatment. The hardness, electrical conductivity, and compressive properties of AMCs were systematically investigated. The results indicate that the reinforcements of 10 and 15 vol % B₄C_p are uniformly distributed, while the reinforcements of 20 vol % B₄C_p present agglomeration in the Al matrix. The hardness of B₄C_p/SiC_p reinforced 2000 series AMCs decreased after increasing, in which the composite with 15 vol % B₄C_p possessed the maximum hardness of 331.9 ± 16.6 HV. In addition, the electrical conductivity of composites decreased with the increase of B₄C_p content. The aluminum matrix composites containing 15 vol % B₄C_p achieved the maximum compressive strength and fracture strain values of 788 MPa and 6.23%, respectively.