Relationships between the accumulative damage and dielectric properties of woven BN-coated Hi-Nicalon™ SiC fibre-reinforced SiC matrix composites
Relationships between the accumulative damage and dielectric properties of woven BN-coated Hi-Nicalon™ SiC fibre-reinforced SiC matrix composites
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DOI：
10.1016/j.ceramint.2015.02.043
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发表时间：
2015-07
影响因子：
5.2
通讯作者：
Shuqi Guo;Y. Kagawa
中科院分区：
文献类型：
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作者：
Shuqi Guo;Y. Kagawa
研究了bn涂层Hi-Nicalon™SiC纤维增强SiC基复合材料在室温和高温拉伸循环载荷下的累积损伤行为。利用迟滞回线得到的损伤参数，定量表征了循环加载过程中的累积损伤。损伤参数随外加应力的增加而增加，直至断裂前基本保持不变。在1 ~ 1000 MHz频率范围内测量了复合材料断裂前后的介电常数、介电损耗和损耗正切。断裂前后介质的介电性能具有相似的频率依赖性。而断裂后试样的介电常数、介电损耗和损耗切线均低于原状试样。介质性能的降低与试样中累积的损伤有关。此外，还详细描述了介质性能与损伤参数之间的关系。
The accumulative damage behaviour of BN-coated Hi-Nicalon™ SiC fibre-reinforced SiC matrix composite was examined under tensile cyclic loading at room and elevated temperatures. The accumulative damage occurring during the cyclic loading was quantitatively characterised using the damage parameter obtained by the hysteresis loop curves. The damage parameter increased with increasing applied stress beyond the matrix cracking stress, and it subsequently retained a nearly constant value until just before fracture. Moreover, the dielectric constant, dielectric loss and loss tangent of the composite were measured before and after the fracture in the frequency range 1–1000 MHz. The dielectric properties had similar frequency dependency before and after the fracture. However, the dielectric constant, dielectric loss and loss tangent were lower in the post-fractured specimens than in the pristine ones. The reduction of the dielectric properties was associated with the accumulative damage stored in the specimens. In addition, the relationships between the dielectric properties and the damage parameter were described in detail.