Spherical indentation of bilayer ceramic structures: Dense layer on porous substrate. Issue 15 (December 2017)

• Record Type: Journal Article
• Authors: Chen, Zhangwei; Wang, Xin; Brandon, Nigel; Atkinson, Alan
• Is Part Of: Journal of the European Ceramic Society. Volume 37:Issue 15(2017)
• Page Start: 4763
• Page End: 4772
• Publication Date: 2017-12
• Subjects: Bilayer structure -- Porous ceramic -- Spherical indentation -- Deformation -- FEM; Ceramic materials -- Periodicals; Composite materials -- Periodicals; Matériaux céramiques -- Périodiques; Composites -- Périodiques; Ceramic materials; Composite materials; Periodicals; Electronic journals; 666.05
• DOI: 10.1016/j.jeurceramsoc.2017.05.053
• Languages: English
• ISSNs: 0955-2219

Abstract

Abstract: Spherical indentation of thin 8YSZ ceramic layers on porous substrates (NiO/Ni-8YSZ) was studied. Indentation-induced elastic and plastic deformation and damage of the bilayer was experimentally analysed. FE simulations of the indentation process were carried out using the Gurson model to account for densification of the porous substrates. The simulated load-depth responses were in excellent agreement with the measured ones. The resulting stress distributions showed that the damage to the YSZ initiates in a tensile region near the interface due to bending during loading at a failure stress of ∼2 GPa, which is consistent with pores of ∼1 μm size seen in the YSZ. Delamination occurs on unloading due to the elastic recovery of YSZ being greater than that of the substrates at a de-bonding stress of 120 MPa. Residual compressive stress in the YSZ inhibits crack opening displacements normal to the layer plane which is beneficial for application of these structures in SOFCs.