Investigation on mechanical properties of silicon nitride composite reinforced by SiC nanoparticles

The design of silicon nitride reinforced by silicon nitride (SiC) nanoparticles is attractive due to its improved high-temperature strength and resistance to oxidation. The high-temperature mechanical behaviors of these composites are difficult to be investigated because it is hard to measure these structural changes in the mechanical test. In this paper, we applied the molecular dynamics simulations to study the effects of size and quantity of SiC clusters on mechanical properties of silicon nitride-based composites. The results show the model with a SiC diameter of 2.4 nm has the largest stress and Young’s modulus, and the stress and Young’s modulus tend to be smaller when the quantity of SiC clusters increases. With an increasing temperature, the Young’s modulus of the structure with the largest clusters decreases before 1300 K and then jumps to 97 GPa at 1500 K, both the loss and jump in Young modulus is related to the interfacial effects between matrix and clusters.