Effect of Dimensional Compatibility Between rGO Sheets and B4C Particles on the Microstructure and Mechanical Properties of rGO–B4C Composites

The effect of dimensional compatibility between rGO sheets and B4C particles plays a critical role in governing the microstructure evolution and mechanical performance of rGO–B4C composites. In this work, rGO–B4C composites (5 wt.% GO addition) with varied initial B4C particle sizes were fabricated via self-assembly polymerization combined with spark plasma sintering. The influence of B4C powder particle size on the microstructure and mechanical properties of rGO–B4C composite ceramics was investigated, and the dimensional compatibility of B4C powder particle size to rGO sheet size was analyzed, further verifying the toughening mechanism of rGO–B4C composite ceramics. The study showed that the dimensional compatibility of rGO sheet size to W3.5 B4C raw material powder particle size is the best. Through self-assembly polymerization combined with spark plasma sintering, a uniformly dispersed and interconnected network structure of rGO in W3.5 rGO–B4C composite ceramics can be obtained. This dense microstructure with an interconnected rGO network helps rGO–B4C composite ceramics achieve optimal mechanical properties, with the highest relative density, hardness, bending strength, and fracture toughness, which are 99.67%, 31.07 GPa, 496 MPa, and 5.45 MPa·m1/2, respectively.