Sintering behavior and mechanical properties of WC–Al2O3 composites prepared by spark plasma sintering (SPS)

Abstract

The sintering behavior of WC–Al2O3 composites prepared via spark plasma sintering (SPS) was investigated. The initial WC–Al2O3 nanocomposite powders were prepared via metal organic chemical vapor deposition in a spouted bed followed by carburization process. Then the nanocomposite powders were densified via SPS at 1400°C. The mechanical properties of sintered disks such as hardness and toughness were analyzed. The WC–Al2O3 composites show maximum toughness of 6.1MPa·m1/2 and hardness value of 24GPa, which are higher than those of monolithic alumina. Microstructure observations indicate that WC nanoparticles are dispersed within the alumina matrix which limit the grain growth of alumina matrix. The fracture mode changes from intergranular in the case of monolithic Al2O3 to transgranular mode for nanocomposites to reinforce their mechanical properties.