Abstract: The B4 C/Al-Mg composites were prepared by compression molding method , the crystal phases and micrographs were analyzed by XRD and SEM .The effect of Mg content and the sinter temperature on the volume density and mechanical properties of composite were studied .The results show:when Al and Mg contents are 37%and 3%, the sintering temperature is 1150 ℃,the mechanical properties of B 4 C/Al-Mg composites are best .The bending strength is 303.67 MPa, hardness is 79.4 HRC and volume density is 2 .40 g/cm3 .

Key words: B4 C/Al-Mg composite material;molding processing method;mechanical property