On the opening of a class of fatigue cracks due to thermo-mechanical fatigue testing of thermal barrier coatings

Coated single crystal superalloys: processing, characterization, and modeling of protective coatings

“…Further mechanical experiments on the same type of coated specimens were performed with a compact radiation furnace in situ in a synchrotron facility [95,105] in order to observe the deformation behaviour of each coating layer during mechanical loading. With these results, it was possible to explain the damage behaviour in TGMF testing and to validate predictive simulation models, which captured the observed behaviour [78,77].…”

“…Figure 1.23: Exemplary damages observed under different thermal and mechanical testing conditions, (a) APS BC and TC after LCF test with R ε =-1 [173], (b) APS BC only, LC after LCF test with R ε =-1, and T=850 • C [88] (c) EB-PVD TC and APS BC, IP-TMF test: R ε =0, ε a =0.7% and 100¡T¡1000 • C [190] (d) IP-TGMF test: R σ =0, σ a =100 MPa and 100¡T¡1000 • C with ∆T=170 • C (through thickness)[77], (e) Coating system after burner rig test in combustion environnement , OP-TGMF test: R σ =0, σ a =800 MPa and 500¡T¡1100 • C with ∆T=150 • C (surface) and ∆T=50-70 • C (through thickness)[106] …”

Simulations Mapping Stress Evolution in High Temperature Ceramic Coatings under Thermal-Mechanical Conditions

“…Numerous studies have been done on modeling crack propagation and delamination of the TBC coatings under various thermal and mechanical fatigue conditions 4,5,6,7 . It has been found that the failure of the coating system often occurs, resulting from the high stresses developed in and around the TGO-Bond Coat interface.…”

Capturing the Competing Influence of Thermal and Mechanical Loads on the Strain of Turbine Blade Coatings via High Energy X-rays

“…Further work with tubular specimens and simultaneous thermal and mechanical loading and adding a thermal gradient has been performed to apply more realistic loading conditions in laboratory testing [19], resulting in spallation and specific crack patterns enhancing spallation [20]. Computational analyses of the experimental findings in [20] provided reasonable explanations for the observed damage features [21,22]; however, for validation of the numerical results, in situ measurement of the strain in all layers of the TBC system was needed. The technique used in [19] has been adapted in [23][24][25] to reveal, by in situ X-ray diffraction, the role of loading variations on the strain of the different layers of a TBC coating system.…”