Full-field characterisation of oxide-oxide ceramic-matrix composites using X-ray computed micro-tomography and digital volume correlation under load at high temperatures

Materials & Design

Dong Liu¹  Jon Ell²  Talha J. Pirzada³  J. Paul Forna-Kreutzer⁴  Robert O. Ritchie⁵  Harold Barnard⁶ 

[1] Department of Materials, University of Oxford, UK;School of Physics, University of Bristol, Bristol, UK;Advanced Light Source, Lawrence Berkeley National Laboratory, Berkeley, CA, USA;Bristol Composites Institute (ACCIS), University of Bristol, Bristol, UK;Cross Manufacturing Company, Bath, UK;Department of Materials Science and Engineering, University of California, Berkeley, CA, USA;

关键词: Oxide-oxide ceramic-matrix composites;    In situ full-field characterisation;    High-temperature X-ray computed micro-tomography;    Digital volume correlation;    Deformation and fracture;   

DOI  :  

来源: DOAJ

【 摘 要 】

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 °C of two Nextel™720/alumina oxide-oxide ceramic-matrix composites (CMCs), termed materials A and B, sintered respectively at 1200 °C and ~1250 °C. At both test temperatures, three-point-bending strengths were ~55–58 MPa for material A and ~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 °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°/90° 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.

【 授权许可】

Unknown