Synthesis and characterization of Al–B4C powders by mechanical alloying

Abstract

Boron carbide reinforced aluminum matrix composites are widely used as neutron absorption materials. Here we report that mechanical alloying has been successfully employed to synthesize metal matrix composite powders with Al as the matrix and B4C as the reinforcement. The effects of powder blending process, solid sintering and thermo-mechanical processes on the microstructure evolution and mechanical properties are studied. The results show that the density of the composites with 30 wt% boron carbide can reach 98.2% after sintering. Thermomechanical processing can increase the density further to 99.4% and remove the defects, leading to an increase in strength from 362.0 to 388.7 Mpa. The influences of boron carbide and processing routes on the mechanical properties and microstructure evolution, specifically the interface between boron carbide and matrix are discussed.