The Effect of adding Zirconium Carbide and Graphene Nanosheets on The Microstructure and Mechanical Properties of ZrB2 Base Composite

In this research,, in order to investigate the effect of adding ZrC on the microstructure and mechanical properties of ZrB2 composites reinforced with graphene nanoplates (GNP), three composites were sintered through spark plasma sintering (SPS) at a temperature of 1900°C for 7 minutes under a pressure of 40 MPa. The sintering behavior,, microstructure and mechanical properties of the resulting composite were also evaluated. The relative density was measured by the Archimedes method. XRD and EDS analysis were used to check the chemical composition and phase identification. Field emission scanning electron microscope (FE-SEM) was used to evaluate the microstructure (grain size and porosity). Bending strength,, hardness and fracture toughness were determined by three-point bending test,, Macro Vickers and Single Edge Notch Beam (SENB) respectively. The results showed that the presence of GNP alone and together with ZrC increases the relative density significantly (99.7%).In addition, full densification was achieved by adding 10 and 20% by volume of ZrC compared to pure ZrB2 ceramics with a relative density of 81%. The maximum hardness, bending strength and fracture toughness of 25.8 GPa, 597 MPa and 4.9 MPa m0.5 were obtained, respectively, for the ZrB2-GNP composite reinforced with 20% by volume of ZrC