A new spallation mechanism of thermal barrier coatings on aero-engine turbine blades. Issue 1 (January 2018)

• Record Type: Journal Article
• Authors: Yuan, Bo; Harvey, Christopher M.; Thomson, Rachel C.; Critchlow, Gary W.; Wang, Simon
• Is Part Of: Theoretical & applied mechanics letters. Volume 8:Issue 1(2018)
• Page Start: 7
• Page End: 11
• Publication Date: 2018-01
• Subjects: Thermal barrier coating -- Interface fracture -- Spallation -- Pockets of energy concentration -- Buckling; Mechanics, Applied -- Periodicals; Mechanics, Analytic -- Periodicals; Mechanics, Analytic; Mechanics, Applied; Periodicals; 620.1
• DOI: 10.1016/j.taml.2018.01.007
• Languages: English
• ISSNs: 2095-0349

Abstract

HIGHLIGHTS: EB-PVD TBCs can spall off at room temperature under constant residual stresses. The mechanism of blister growth relies on pockets of energy concentration (PECs). The nucleation and stable growth of the blister are driven by PECs. The unstable growth and spallation of the blister are driven by PECs and buckling. ABSTRACT: Laboratory experiments were conducted to study the spallation behaviour of thermal barrier coatings (TBCs) on aero-engine turbine blades manufactured by the electron-beam physical vapour deposition technique (EB-PVD). Intact blades were heated at temperature 1135°C in a furnace for certain time and then cooled to the room temperature in the laboratory condition. It was found that no spallation occurred during cooling, but spallation happened at constant room temperature after cooling. The spallation mechanism is studied by using the mechanical model developed (Harvey 2017 and Wang 2017), which are based on the hypothesis of pockets of energy concentration (PECs). Some observations of the spallation behaviour are well predicted by the model.