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根据热防护系统的特征载荷,研究了气凝胶的室温、高温压缩和压缩蠕变性能。研究表明纤维增强SiO2气凝胶的压缩曲线可划分为三个阶段:线性阶段、屈服阶段和密实化阶段。相比纯气凝胶,该材料具有较高的强度、良好的断裂韧性。该材料存在明显的室温和高温蠕变行为。室温条件下240h内的蠕变历程可划分为三个阶段,在168h以后蠕变变形量达到稳定状态,基本不再继续增加。对比试样在试验前、热处理后和蠕变试验后的显微结构发现,气凝胶基体的密实化是加热后试样收缩和影响气凝胶蠕变性能的主要因素。
According to the characteristic load of the thermal protection system, the aerogels were studied at room temperature, high temperature compression and compressive creep properties. The research shows that the compression curve of fiber-reinforced SiO2 airgel can be divided into three stages: linear stage, yield stage and densification stage. Compared to pure airgel, the material has high strength, good fracture toughness. The material has obvious creep behavior at room temperature and high temperature. The creep course within 240 hours at room temperature can be divided into three stages. After 168 hours, the creep deformation reaches a steady state and basically no longer continues to increase. The microstructure of the control samples before and after the heat treatment and creep test found that the densification of the airgel matrix is the main factor that causes the shrinkage of the sample after heating and affects the creep properties of the airgel.