Enhanced mechanical properties and ablation resistance of ZrC_w/ZrB₂-SiC composites

In this paper, ZrC whisker reinforced ZrB₂-SiC (ZrC_w/ZrB₂-SiC) composites were prepared by the spark plasma sintering (SPS) method. The results show that the relative density （RD） of composites decreases with the increase of whisker content due to the overlapping of whiskers. When the whisker content increases from 0 % to 20 %, RD decreases from 97.2 % to 93.2 %. The decrease in density resulted in a slight decrease in the strength of the composite from 597.1 to 562.9 MPa. However, the toughness increased significantly from 6.27 MPa·m^1/2 to 8.46 MPa·m^1/2. When the whisker content is 10 %, ZrC_w/ZrB₂-SiC composite shows the best comprehensive ablation resistance. After ablation at 4.18 MW/m² for 40 s, it can remain intact without cracking and the mass ablation rate decreases from 2.0 mg/s to 1.5 mg/s.