Determination of Subcritical Crack Growth Parameters in Polymer‐Derived SiOC Ceramics by Biaxial Bending Tests in Water Environment
Determination of Subcritical Crack Growth Parameters in Polymer‐Derived SiOC Ceramics by Biaxial Bending Tests in Water Environment
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水环境中双轴弯曲试验测定聚合物衍生SiOC陶瓷中的亚临界裂纹扩展参数
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发表时间：
2010
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通讯作者：
Michael J. Hoffmann
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作者：
K. G. Schell;E. Bucharsky;R. Oberacker;Michael J. Hoffmann
在1600°C下采用场助烧结法制备了聚合物衍生的SiOC陶瓷。为了表征这种材料，进行了X射线衍射、密度测量和机械测试。经测定，该材料是致密的，并且主要是非晶的，具有β-SiC的精细结晶区域。单边V形缺口弯曲试验测得其断裂韧性为0.84MPa·m1/2。惰性强度和亚临界裂纹扩展参数来自于在不同加载速率下进行的球对三球试验。212 MPa的惰性强度和15的裂纹扩展指数n处于与通常预期的二氧化硅基玻璃相似的水平。由于增强的裂纹扩展参数A0，在给定的应力强度水平的SiOC材料的裂纹速度显着降低相比，二氧化硅玻璃。
Polymer-derived SiOC ceramics were prepared by field-assisted sintering at 1600°C. In order to characterize this material, X-ray diffractometry, density measurements, and mechanical tests were performed. It was determined that the material is dense and predominantly amorphous with fine crystalline regions of β-SiC. A fracture toughness of 0.84 MPa · m 1/2 was determined from single edge, v-notched bending tests. Inert strength and subcritical crack growth parameters were derived from the ball-on-three-balls tests carried out at different loading rates. The inert strength of 212 MPa and the crack growth exponent n of 15 are on a similar level as commonly expected for silica-based glasses. Because of an enhanced crack growth parameter A 0 , the crack velocity of the SiOC material at a given stress intensity level is significantly reduced compared with silica glasses.