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In this paper, the two‐dimensional (2D) (0°/90°) plain‐woven Amosic‐3 SiC/SiC turbine guide vane (TGV) was fabricated using the chemical vapor infiltration method. Thermal and stress analysis of the TGV was conducted using the finite element method analysis. Multiple thermal shock tests at T = 1250, 1350, 1400, 1420, 1450, 1470, and 1480°C were conducted for N = 100, 100, 400, 300, 200, 200, and 700 cycles. After thermal shock tests, the surface damage of the TGV was observed visually, and the micro damage mechanism was analyzed using the scanning electronic microscopy. Micro X‐ray computed tomography was adopted to characterize the internal damages in the SiC/SiC guide vanes. The delamination occurred at the positions approaching internal hollow, due to the weak binding force along the thickness direction and the high thermal shock stress caused by the temperature change. The diameter, area, volume, and sphericity distributions of the pores inside of the guide vanes were also obtained. [ABSTRACT FROM AUTHOR]

Carbon fiber-reinforced carbon matrix (C/C) composites were prepared by chemical vapor infiltration, and then they were subjected to silicon (Si) reactive melt infiltration to obtain C/C–SiC–Si composites. The ablation behavior of these two types of composites was evaluated by high-energy (500w) carbon dioxide laser irradiation under argon atmosphere. The depths and three-dimensional (3D) profiles of laser ablation holes were measured by laser confocal microscopy. The results showed that the depth of ablation hole of C/C composites gradually increased, and the ablation rate decreased with ablation time. The temperature distribution on C/C composite surface was simulated by 3D finite element analysis. The C/C–SiC–Si composites exhibited a rapid ablation rate during the ablation process within 7 s; however, no further ablation damage on carbon matrix was observed after 7 s. Si was found to dissipate energy through phase change, transpiration cooling, and smog attenuation. A laser ablation model was proposed based on the energy dissipation mechanism. C/C–SiC–Si composite showed better performance of laser ablation resistance in 100 s than pure C/C composite. Image 1 • A long time (max-100s) and strong power (500w) laser ablation test was carried out on carbon/carbon composite. • Laser ablation behavior of carbon/carbon composite in inert atmosphere was studied. • Silicon-modified carbon/carbon material can produce the double effects of sweating cooling and smoke attenuation to the laser energy. • The material has skeleton phase and filling phase structure can effectively resist laser ablation. [ABSTRACT FROM AUTHOR]

Abstract: Tensile test was used upon a 3D-C/SiC composite under air or nitrogen atmosphere to characterize its mechanical behaviors and associated damage evolutions from room to cryogenic temperatures. The tensile strength relatively weakened most at −40°C, however, that is recovered as temperature decreasing to −100°C. The mismatch of coefficient of thermal expansions between carbon fiber and SiC matrix plays a role in this mechanical response. An interfacial damage model based on microscopic observation is proposed. Finite element method is used to analysis C/SiC deformations. Some generalizations were provided under the cryogenic environment. [Copyright &y& Elsevier]