Abstract
In order to understand the influence of the mechanisms of ZrC nanoparticles on the high-temperature mechanical properties of C-SiC ceramic matrix composites, the mechanical properties were measured from room temperature (RT) to 1600 °C under vacuum. The microstructures features were characterized by scanning electron microscopy. In comparison with the composites without ZrC nanoparticles, the ZrC-modified composite presented better mechanical properties at all temperatures, indicating that the mechanical properties could be improved by the ZrC nanoparticles. The ZrC nanoparticles could reduce the residual silicon and improve the microstructure integrity of composite. Furthermore, the variation of flexural strength and the flexural modulus showed an asynchronous trend with the increase of temperature. The flexural strength reached the maximum value at 1200 °C, but the highest elastic modulus was obtained at 800 °C. The strength increase was ascribed to the decrease of the thermally-induced residual stresses. The degradation of mechanical properties was observed at 1600 °C because of the microstructure deterioration and the formation of strongly bonded fiber–matrix interface. Therefore, it is concluded that the high temperature mechanical properties under vacuum were related to the consisting phase, the matrix microstructure, and the thermally-induced residual stresses.
Highlights
Carbon fiber-reinforced silicon carbide-based matrix (C/C-SiC) composites have been attracting increasing attention in the development of aerospace technology because of their lightweight, superior high-temperature mechanical properties, good oxidation resistance, and excellent thermal shock resistance [1,2,3,4,5,6]
The high-temperature mechanical properties of the ZrC-modified C-SiC composites fabricated by a hybrid process were measured from room temperature (RT) to 1600 °C under vacuum
The high-temperature mechanical properties of the ZrC-modified C-SiC composites fabricated by a hybrid process were measured from RT to 1600 ◦ C under vacuum
Summary
Carbon fiber-reinforced silicon carbide-based matrix (C/C-SiC) composites have been attracting increasing attention in the development of aerospace technology because of their lightweight, superior high-temperature mechanical properties, good oxidation resistance, and excellent thermal shock resistance [1,2,3,4,5,6]. Under the high temperature oxidative environments, it is difficult to understand the intrinsic influence mechanisms (related to the microstructure evolution and the internal stress variation etc.) on the mechanical properties of composites because of the multi-mechanisms activated in such environment. In previous work [19], it was found the introduction of ZrC could improve the anti-oxidation resistance and the high temperature mechanical properties of carbon fiber-reinforced C-SiC matrix composites under oxidative environment. Due to the obvious oxidation at high temperature, it is difficult to understand how the intrinsic microstructure, matrix phase and the internal stress variation impact the mechanical properties. Combining the mechanical properties with the microstructures and the analysis of residual stresses, the intrinsic mechanisms on the mechanical properties were analyzed and discussed
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