Microstructure dependent physical and mechanical properties of spark plasma sintered ZrB2-MoSi2-SiCw composites

A comparative evaluation has been carried out off the physical and mechanical properties of ZrB2-20 vol% MoSi2 composites reinforced with 5, 10 and 20 vol% SiC whiskers (SiCw). The abovementioned hybrid composites have been densified by spark plasma sintering (SPS) at 1600 degrees C for 10 min. The present study focuses on the effect of the quantity of SiCw on the densification, electrical conductivity, hardness, and fracture toughness ZrB2-MoSi2-SiCw composites in detail. Microstructural characterization suggests that SiCw restricts the grain growth of ZrB2 during densification. The electrical conductivities of the ZrB2-MoSi2-SiCw composites have been found to vary in the range similar to 2.4-3.5 x 10(6) S/m, and it reduce with increasing SiCw content. Results exhibit that the indentation fracture toughness of ZrB2-20 vol% MoSi2 improves similar to 70%, similar to 112% and similar to 130% with an addition of 5, 10 and 20 vol% SiCw, respectively. An increase in SiCw content leads to more amount of crack deflection and crack arrest that successively improves the fracture toughness of the composites.