Hardness and Indentation Fracture Toughness in a Novel Silicon Composite Synthesized by Spark Plasma Sintering

A composite of 90 wt pct silicon and 10 wt pct of the multi-component Mo44Si26Ta5Zr5Fe3Co12Y5 was synthesized using spark plasma sintering at a temperature of 1423 K and applied pressure of 75 MPa. The relative density of the composite following the spark plasma sintering was found to be 99 pct. Indentation fracture toughness measurements in the composite using a Vickers diamond indenter yielded a value of 2.29 MPa m1/2 which is higher than that of elemental silicon at 1.43 MPa m1/2. The second phase provided an average hardness of 14 GPa, while silicon demonstrated hardness of 12 GPa.