材料期刊网

The ablation properties of C/C composites with four different needled preforms prepared by isothermal chemical vapor infiltration (ICVI), which are super-thin mat lay-up, 0 degrees/90 degrees weftless fabric lay-up, 0 degrees/45 degrees weftless fabric lay-up and 0 degrees/45 degrees twill fabric lay-up, were quantitatively evaluated by performing the ablation tests with an engine torch. And their ablation discrepancies were analyzed according to the surface characteristic, porosity and thermal diffusivity. The results show that the 0 degrees/45 degrees weftless composite has a flat eroded surface with no obvious macroscopic pits. Its thickness and mass erosion rates are decreased by about 46.8% and 34.8%, 25.0% and 27.5%, and 17.5% and 19.4% compared with those of the mat, the 0 degrees/90 degrees weftless and the 0 degrees/45 degrees twill composites, respectively. The ablation properties are mainly controlled by the thermo-chemical effect (oxidation), and a little by the thermo-mechanical effect (mechanical denudation). The needling fiber bundles play an important role in accelerating the ablation process and resulting in the heterogeneous ablation.