Fracture behavior under mixed-mode loading of ceramic plasma-sprayed thermal barrier coatings at ambient and elevated temperatures

• Published in: Engineering fracture mechanics 2005-09, Vol.72 (13), p.2144-2158
• Main Authors: Choi, S.R., Zhu, D., Miller, R.A.
• Format: Article
• Language: English
• Subjects: Asymmetric four-point flexure; Ceramic thermal barrier coatings; Exact sciences and technology; Fracture mechanics (crack, fatigue, damage...); Fracture toughness testing; Fundamental areas of phenomenology (including applications); Mixed modes I and II loading; Physics; Plasma-sprayed ZrO 2–8wt%Y 2O 3; Solid mechanics; Static elasticity (thermoelasticity...); Structural and continuum mechanics
• ISSN: 0013-7944; 1873-7315
• DOI: 10.1016/j.engfracmech.2005.01.010

The fracture behavior under modes I and II loading of ceramic plasma-sprayed thermal barrier coatings was determined in air at 25 and 1316 °C in asymmetric four-point flexure. The mode I fracture toughness was found to be K Ic = 1.15 ± 0.07 and 0.98 ± 0.13 MPa m , respectively, at 25 and 1316 °C. The respective ‘ nominal’ mode II fracture toughness values were K IIc = 0.73 ± 0.10 and 0.65 ± 0.04 MPa m . The empirical mixed-mode fracture criterion best described the coatings’ fracture behavior under mixed-mode loading. The angle of crack propagation was in reasonable agreement with the minimum strain energy density criterion.