Connected ceramic preforms （B4C） with porosity of 46.8% were fabricated by pressureless sintering in vacuum

then B4C/Al-Si composites with high ceramic fraction were prepared by pressureless infiltrating aluminum alloy A356 into the boron carbide preforms B4C

whose relative density

compressive strength and flexure strength are more than 99%

453MPa and 294MPa

respectively. Microstructural observation reveals that prepared composites exhibit compact structure and desirable interface bonding

in which formed Al

Si and Al3BC phases are uniformly distributed. Al phase is mainly distributed in the cavity of B4C frames and Si mainly existed in the interface of B4C and Al phase

which results in the tough combination of B4C and Al phases

meanwhile

uniformly distributed Al phase can be observed in surface and inner of composite samples. B4C ceramics is formed continuous frame in the fabricated B4C/Al-Si composites and metallic phase existed in the cavity plays the role in toughening and strengthening effects.