Full-field characterisation of oxide-oxide ceramic-matrix composites using X-ray computed micro-tomography and digital volume correlation under load at high temperatures
Full-field characterisation of oxide-oxide ceramic-matrix composites using X-ray computed micro-tomography and digital volume correlation under load at high temperatures
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DOI：
10.1016/j.matdes.2021.109899
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发表时间：
2021-06-19
影响因子：
8.4
通讯作者：
Liu, Dong
中科院分区：
文献类型：
--
作者：
Forna-Kreutzer, J. Paul;Ell, Jon;Liu, Dong
利用原位同步加速器x射线计算机微断层扫描和数字体积相关（DVC）来了解两种称为材料A和B的Nextel (TM) 720/氧化铝-氧化物陶瓷基复合材料（cmc）在室温和1050℃下的失效机制，这两种材料分别在1200℃和1250℃烧结。材料A的三点弯曲强度为55-58 MPa，材料b的三点弯曲强度为94-100 MPa。损伤与三种主要的开裂模式有关：界面剥离、纤维束内倾斜裂缝、现有基体收缩裂缝的打开。材料A表现出较高的收缩开裂，而材料B表现出更明显的对角基体微开裂。在1050℃时，两种体系都表现出较少的微裂纹，但更明显的分层。根据相应的三维DVC位移/应变场对这些损伤特征进行了合理化。具体来说，利用了全局DVC，破坏前的最大主应变位置（从0.005到0.01不等）与破裂起裂位置具有良好的相关性。此外，观察到剪切应变分量的突然正向负转变，这归因于0度/90度纤维与基体之间不同的结合强度。目前的研究表明，原位高温层析成像/DVC是研究氧化-氧化cmc变形和断裂的有力方法。(C) 2021作者。Elsevier Ltd.出版。
In situ synchrotron X-ray computed micro-tomography and digital volume correlation (DVC) were utilised to understand the failure mechanisms at room temperature and 1050 degrees C of two Nextel (TM) 720/alumina oxide-oxide ceramic-matrix composites (CMCs), termed materials A and B, sintered respectively at 1200 degrees C and similar to 1250 degrees C. At both test temperatures, three-point-bending strengths were similar to 55-58 MPa for material A and similar to 94-100 MPa for material B. Damage was associated with three primary types of cracking modes: interfacial delamination, inclined cracks within fibre tows, opening of existing matrix shrinkage cracks. Material A exhibited higher shrinkage cracking, whereas material B displayed more pronounced diagonal matrix microcracking. At 1050 degrees C, both systems showed less microcracking but more pronounced delamination. Such damage characteristics were rationalised in terms of the corresponding 3D DVC displacement/strain fields. Specifically, global DVC was utilised and maximum principal strain locations prior to failure, which varied from 0.005 to 0.01, correlated well to the fracture initiation sites. Further, abrupt positive to negative transitions of shear strain components were observed and were attributed to the different bonding strengths between 0 degrees/90 degrees fibres and the matrix. The current study demonstrates that in situ high-temperature tomography/DVC is a powerful method for studying the deformation and fracture of oxide-oxide CMCs. (C) 2021 The Authors. Published by Elsevier Ltd.