CORROSION KINETIC AND LIFE PREDICTION EQUATION OF AN SiC-C/SiC COMPOSITE UNDER LOW FREQUENCY CYCLE STRESS AT HIGH TEMPERATURES
-
摘要: 研究了SiC涂层连续碳纤维增韧的SiC基复合材料(SiC-C/SiC)在低频拉-拉循环应力下,干氧环境、水蒸气环境、湿氧环境以及含硫酸钠蒸气环境中,1000℃、1200℃和1300℃高温下的应力氧化与应力腐蚀情况。通过比较复合材料在相同循环应力条件下、不同温度和环境中的寿命,揭示了复合材料在高温、循环应力状态下的腐蚀机理。研究发现,在循环应力状态下,氧气是导致SiC-C/SiC复合材料寿命下降的主要因素。1000℃<T<1300℃时,循环应力作用下SiC-C/SiC复合材料的失效机制是由碳纤维和氧气的反应机制控制的,其寿命随温度升高而线性下降。提出了SiC-C/SiC复合材料在拉-拉循环应力作用下的寿命预测公式,并利用试验结果验证了其正确性。Abstract: Stress oxidation and stress corrosion of an SiC-C/SiC composite under low frequency tensile-tensile cycle stress in multi-atmospheres at 1000℃, 1200℃ and 1300℃ were studied. The atmospheres include dry oxygen, water vapor, wet oxygen and Na2SO4 vapor mixed gas.The stress corrosion kinetic of the composite at 1300℃ was discussed by comparing the differences of lives when the specimens were exposed at different temperatures and in different atmospheres under the same cycle stress. It was found that oxygen is the major factor decreasing the life of the SiC-C/SiC composite under low frequency cycle stress at 1300℃. And the oxidation kinetic is controlled by the reaction between carbon fibers and oxygen under low frequency cycle stress between 1000℃ and 1300℃. The life prediction equation of SiC-C/SiC composites under cycle stress is suggested and validated well by experimental results.
-
-
计量
- 文章访问数: 1664
- HTML全文浏览量: 68
- PDF下载量: 914
下载:
