Damage mechanisms of C/SiC composites subjected to constant load and thermal cycling in oxidizing atmosphere
Damage mechanisms of C/SiC composites subjected to constant load and thermal cycling in oxidizing atmosphere
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DOI：
10.1016/j.scriptamat.2005.09.044
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发表时间：
2006
影响因子：
6
通讯作者：
H. Mei;Lai-fei Cheng;Litong Zhang
中科院分区：
文献类型：
--
作者：
H. Mei;Lai-fei Cheng;Litong Zhang
在恒定负载、热循环和湿氧气氛等受控环境下研究了碳纤维增强碳化硅基复合材料的性能。通过残余机械性能和扫描电子显微镜表征来评估损坏。结果表明，热应变会随着同一时期（120 秒）内的循环温度而变化。在测试的短时间内，应变变化大约从初始线性弹性应变 0.63% 到最终不可逆损伤应变 1.6%。两个选定温度的实验应变差约为0.16%，理论计算值为0.1566%。经过50次热循环后，复合材料的杨氏模量降低了0.5倍，而残余强度仍保持初始强度的82%。观察到涂层表面存在横向的基体裂纹和呈波浪状的裂纹，且裂纹间距较为规则。沿着涂层下方的开口和扩展裂纹可以发现典型的表面氧化。
Properties of a carbon fiber reinforced silicon carbide matrix composite were investigated in controlled environments including constant load, thermal cycling and wet oxygen atmosphere. Damage was assessed by residual mechanical properties and scanning electron microscopy characterization. Thermal strain was shown to change with cyclic temperatures over the same period (120s). Strain varies approximately from the initial linear elastic strain of 0.63% to the final nonreversible damage strain of 1.6% during the short time of the test. The experimental strain difference between two selected temperatures is about 0.16% and the theoretical calculation value is 0.1566%. After 50 thermal cycles, the Young’s modulus of the composites is reduced by a factor of 0.5 while the residual strength still retains 82% of the initial strength. It is observed that matrix cracks transversely and wave-shaped cracks are arranged on the coating surface at relatively regular spacing. A typical superficial oxidation can be found along the opening and propagating cracks beneath the coating.