A physics-based life prediction methodology for thermal barrier coating systems

Research output: Contribution to journalArticle

Authors

  • EP Busso
  • L Wright
  • LN McCartney
  • SRJ Saunders
  • S Osgerby
  • J Nunn

Colleges, School and Institutes

Abstract

A novel mechanistic approach is proposed for the prediction of the life of thermal barrier coating (TBC) systems. The life prediction methodology is based on a criterion linked directly to the dominant failure mechanism. It relies on a statistical treatment of the TBC's morphological characteristics, non-destructive stress measurements and on a continuum mechanics framework to quantify the stresses that promote the nucleation and growth of microcracks within the TBC. The last of these accounts for the effects of TBC constituents' elasto-visco-plastic properties, the stiffening of the ceramic due to sintering and the oxidation at the interface between the thermally insulating yttria stabilized zirconia (YSZ) layer and the metallic bond coat. The mechanistic approach is used to investigate the effects on TBC life of the properties and morphology of the top YSZ coating, metallic low-pressure plasma sprayed bond coat and the thermally grown oxide. Its calibration is based on TBC damage inferred from non-destructive fluorescence measurements using piezo-spectroscopy and on the numerically predicted local TBC stresses responsible for the initiation of such damage. The potential applicability of the methodology to other types of TBC coatings and thermal loading conditions is also discussed. (c) 2006 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

Details

Original languageEnglish
Pages (from-to)1491-1503
Number of pages13
JournalActa Materialia
Volume55
Issue number5
Publication statusPublished - 1 Mar 2007

Keywords

  • MCrAlY, life prediction model, finite element modelling, TBC