High temperature fracture toughness and residual stress in thermal barrier coatings evaluated by an in-situ indentation method. Issue 7 (May 2018)

• Record Type: Journal Article
• Authors: Qu, Zhaoliang; Wei, Kai; He, Qing; He, Rujie; Pei, Yongmao; Wang, Shixing; Fang, Daining
• Is Part Of: Ceramics international. Volume 44:Issue 7(2018)
• Page Start: 7926
• Page End: 7929
• Publication Date: 2018-05
• Subjects: TBCs -- In-situ indentation method -- High temperature fracture toughness -- High temperature residual stress; Ceramics -- Periodicals; Céramique industrielle -- Périodiques; Ceramics; Periodicals; Electronic journals; 666
• DOI: 10.1016/j.ceramint.2018.01.230
• Languages: English
• ISSNs: 0272-8842

Abstract

Abstract: High temperature fracture toughness and residual stress are important for the evaluation of TBCs. In this paper, an in-situ high temperature indentation method was originally developed to investigate the high temperature fracture toughness and residual stress in a typical TBC, nanostructured 8 wt% yttria partially stabilized zirconia (YSZ) coating. The cracks caused by in-situ high temperature indentation tests were observed, and high temperature fracture toughness and residual stress were experimentally measured. The fracture toughness was measured to be 1.25, 0.91 and 0.75 MPa*m 1/2 at 25, 800 and 1000 °C, respectively. The residual stress was measured to be − 131.3, − 55.5 and − 45.5 MPa, correspondingly. Moreover, the residual stress and fracture toughness both decrease with increasing environmental temperature. It is also found that the fracture toughness without consideration of residual stress is significantly larger than the intrinsic fracture toughness, which may result from the compressive stress state.