Ablation behavior of SiCf/SiC composites in arc wind tunnel

Purpose Continuous SiC fiber-reinforced SiC matrix composites (SiCf/SiC) have a wide application prospect in aerospace fields due to their excellent high-temperature performance, corrosion resistance and oxidation resistance. SiCf/SiC composites face significant challenges under extreme aerothermal environments, which will cause oxidation-induced interphase degradation, thermal stress and surface ablation damage. The paper aims to investigate the ablation behavior of SiCf/SiC composites by using the arc wind tunnel test for the application of the material. Design/methodology/approach SiCf/SiC composites are subjected to single and five cycles of ablation by using the arc wind tunnel tests. The influence of machining processes on ablation resistance is investigated via comparative analysis of mechanical properties. Microstructural evolution before and after ablation is characterized using scanning electron microscopy, and the ablation mechanism is further revealed. Findings The results reveal that after single ablation, the composites exhibit negligible changes in tensile and flexural strengths. After five-cycle ablations, the tensile strength exhibits a substantial enhancement. Microstructural analysis suggests that passive oxidation predominantly occurred during the process of ablation, resulting in low ablation rates and the formation of dense oxide layers. These oxide layers effectively seal surface pores and microcracks, leading to maintain or even improve the mechanical properties. Originality/value This research provides essential experimental data and theoretical insights for understanding the ablation mechanisms of SiCf/SiC composites in high-temperature gas flow environments, while also offering technical support for their advanced aerospace applications.