A piston-on-three-ball assembly is employed to evaluate the biaxial strength of the ceramic top-coat in thermal barrier coating system (TBCs). The design of bi-axial experiment is presented, in which the effects of the specimen geometric parameters, the contact between the specimen and the support, and the plastic deformation of substrate are numerically analyzed. Then, the piston-on-three-ball tests and Scanning Electron Microscopy (SEM) observations are carried out to measure the bi-axial strength and the failure patterns of the ceramic top-coat in TBCs, respectively. We experimentally obtained the bi-axial fracture strength of the ceramic top-coat in thermal barrier coating system, which obeys Weibull distribution function. The fracture patterns of the ceramic top-coat under bi-axial loading exhibit a typical channel network. © 2015 Elsevier Ltd and Techna Group S.r.l. All rights reserved.
Bibliographical noteThis work is supported by China 973 Program (2013CB035701) and NSFC (11321062 and 11172227). XC acknowledges additional support from NSFC (11172231 and 11372241) and AFOSR (FA9550-12-1-0159). LCS is supported by China Scholarship Council as a visiting scholar at Columbia University.
- Bi-axial strength
- Piston-on-three-ball test
- Thermal barrier coating