In order to reveal the effect of matrix cracks resulted from thermal residual stresses (TRS) on the thermal expansion behavior of ceramic matrix composites, SiBC matrix was introduced into C_f/SiC and SiC_f/SiC by liquid silicon infiltration. The TRS in both two composites were enlarged with incorporating SiBC matrix which has higher coefficients of thermal expansion (CTEs) than SiC matrix. Due to the relatively high TRS, matrix cracks and fiber/matrix (f/m) debonding exist in C_f/SiC-SiBC, which would provide the space for the expansion of matrix with higher CTEs. For SiC_f/SiC, no matrix cracking and f/m debonding took place due to the close CTEs between fiber and matrix. Accordingly, with the incorporation of SiBC matrix, the in-plane CTE of C_f/SiC between room temperature to 1100 °C decreases from 3.65 × 10⁻⁶ to 3.19 × 10⁻⁶ K^-1, while the in-plane CTE of SiC_f/SiC between room temperature to 1100 °C increases slightly from 4.97 × 10⁻⁶ to 5.03 × 10⁻⁶ K^-1.

为了揭示由残余热应力（TRS）引起的基体裂纹对陶瓷基复合材料热膨胀行为的影响，通过液硅渗透将SiBC基体引入C _f / SiC和SiC _f / SiC中。两种复合材料的TRS均通过掺入SiBC基体而得以扩大，而SiBC基体的热膨胀系数（CTE）比SiC基体高。由于较高的TRS，C _f / SiC-SiBC中存在基体裂纹和纤维/基体（f / m）脱胶，这将为具有较高CTE的基体扩展提供空间。对于SiC _f/ SiC，由于纤维和基体之间的CTE紧密，因此不会发生基体开裂和f / m剥离。因此，通过掺入SiBC矩阵，室温至1100°C时C _f / SiC的面内CTE从3.65×10 ^-6降低到3.19×10 ^-6  K ^-1，而Cf / SiC的面内CTE降低。室温至1100°C之间的SiC _f / SiC从4.97×10 ^-6略增至5.03×10 ^-6  K ^-1。