3German Aerospace Center (DLR), Cologne, Germany ...
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Introduction Objectives References Acknowledgements Future Work Analysis Synchrotron X-ray Measurement Techniques 1 Mechanical, and Aerospace Engineering, College of Engineering and Computer Science, University of Central Florida, Orlando, FL 32816, USA 2 Advanced Photon Source, Argonne National Laboratory, Argonne, IL, USA 3 German Aerospace Center (DLR), Cologne, Germany In-situ Synchrotron Analysis of Thermal Barrier Coatings under Thermal Gradients and Mechanical Loads Pascal Fouquet 1 , Frank Ramirez 1 , Stephen Sofronsky 1 , Albert Manero 1 , Kevin Knipe 1 , Carla Meid 3 , Janine Wischek 3 , John Okasinski 2 , Jonathan Almer 2 , Marion Bartsch 3 , and Seetha Raghavan 1 Develop techniques to apply thermal gradient and mechanical loading while maintaining access to high energy x-ray measurements Develop measurement techniques to accurately obtain in-situ X-ray diffraction (XRD) strain measurements of each internal layer of the tubular sample Determine strain behavior of coating layers under thermal gradient and mechanical loading conditions Results Thermal Gradient and Mechanical Single Cycles Aged samples have a thicker and more developed TGO layer due to repeated cycling Analyze strains in aged samples to establish quantitative strain relief and observe damage mechanisms Crack formation in an aged sample, by M. Bartsch et al., 2008 K. Knipe, A. Manero, S. Siddiqui, C. Meid, J. Wischek, J. Okasinski, J. Almer, A. Karlsson, M. Bartsch, and S. Raghavan, Effects of Thermal Gradient and Mechanical Loading on In-Cycle Strains for Thermal Barrier Coatings Determined through Synchrotron XRD Measurements , (In Review) M. Bartsch, B. Baufeld, S. Dalkiliç, L. Chernova, M. Heinzelmann, Fatigue cracks in a thermal barrier coating system on a superalloy in multiaxial thermomechanical testing International Journal of Fatigue , 30(2008), p. 211 S. Siddiqui, K. Knipe, A. Manero, C. Meid, J. Wischek, J. Okasinski, J. Almer, J. Schneider, M. Bartsch, S. Raghavan, Synchrotron X-ray Measurement Techniques for Thermal Barrier Coated Cylindrical Samples Rev Sci Instrum, 84(2013), p. 8 There is an increasing need to extend the operational temperature limits of turbine components. Thermal barrier coatings combined with internal substrate cooling allow for operating temperatures exceeding the melting temperatures of the turbine substrate. The thermal expansion mismatch between the different materials however, result in large residual stresses that are linked to failure. In-situ synchrotron diffraction provides the means to establish the evolution of strain at high resolution. The X-rays diffract onto a high resolution 2-D detector in the form of distorted rings The elliptical state of the ring is indicative of strain X-Ray Scan Through Coating Thickness Window Size 30 x 300 microns 10 Window Scan BC YSZ Exhaust Air Controller /Computer Thermocouples Flow Controller Coolant: Compressed Air X-ray Beam Heat to Sample Coolant Experimental Diagram MTS MTS This material is based upon work supported by the National Science Foundation grants (Grant Nos. OISE 1157619 and CMMI 1125696) and by the German Science Foundation (DFG) grant (Grant No. SFB-TRR103), Project A3 Use of the Advanced Photon Source at Argonne National Laboratory was supported by the U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences, under Contract No. DE-AC02-06CH11357 1.6 1.8 2 2.2 2.4 2.6 2.8 3 3.2 0 2 4 6 8 10 Plot of d spacing vs intensity of material peaks scanned with the highlighted section showing the thermal expansion of the bond coat due to the increasing thermal gradient Loading Conditions A) At room temperature, YSZ expresses compressive in-plane strain (e22) B) The bond coat expresses tensile in-plane strain (e22) As the surface temperature is ramped up to high temperature, both layers then relaxes to zero strain A) A) When strain is induced on a lattice structure, the diffraction angle is altered due to Braggs Law B) The change in diffraction angle results in an elliptical distortion of the diffraction ring C) Identifying the zero strain reference angle D) Bond coat strain results at an individual measurement for the experiment with a 128Mpa load and 40 liters/min flow rate The thermal barrier coating (TBC) is adhered to the surface of the turbine blade by a nickel based bond coat and the blade is forced cooled with air by an internal coolant channel. Experiment in progress Variations in Thermal Gradients With increasing thermal gradient, the YSZ demonstrates minimal change in strain from the outer surface into the middle of the layer The inner region of the YSZ displays a significantly increasing compressive strain and thus higher strain gradient Inner YSZ Radius Outer YSZ Radius YSZ (111) e22 strain displayed the YSZ thickness at various thermal gradients Variations in Mechanical Load Strain relationships of YSZ and bond coat with respect to axial load at various temperatures The YSZ and NiAl in the bond coat gradually bear less of the applied load as temperature increases Inelastic behavior is experienced in the bond coat above 800 o C, as is displayed by the flat strain response to mechanical load Loading Conditions The experiment was conducted at Argonne National Laboratory Orientation of e22 and e11 with respect to the sample A) B) 2-D Unstrained Ring 2-D Strained Ring Azimuthal Angle Zero Strain Reference Angle B) C) Azimuthal Angle 50 100 150 200 250 300 350 511.5 512 512.5 513 513.5 514 514.5 Radial Position (Pixels) Increasing Load Ro η* Sample IN 100 Substrate Outside Diameter = 8mm Inside Diameter = 4mm NiCoCrAlY Bond Coat 80 μm EB-PVD Coating α-Al2O3 Oxide Layer (TGO) As-Coated 0.5 μm Thickness Yttria Stabilized Zirconia (YSZ) EB-PVD 240 μm Coating Cylindrical sample manufactured at DLR Pratt and Whitney F-119 engine Lockheed Martin F-22 Raptor Turbine Blade metal alloy Bond Coat TGO TBC Combustion gases Temperature Displacement Operating Temperature Blade Melting point Cross Section of Turbine Blade Coolant Channel D) Bond Coat YSZ 45 90 135 180 225 270 315 -5 0 5 10 x 10 -4 Diffraction Strain (Ro-R)/Ro ε 22 ε 11 η* Azimuthal Angle
Transcript of 3German Aerospace Center (DLR), Cologne, Germany ...
Introduction
ObjectivesReferences
Acknowledgements
Future Work
AnalysisSynchrotron X-ray Measurement Techniques
1Mechanical, and Aerospace Engineering, College of Engineering and Computer Science, University of Central Florida, Orlando, FL 32816, USA2Advanced Photon Source, Argonne National Laboratory, Argonne, IL, USA
3German Aerospace Center (DLR), Cologne, Germany
In-situ Synchrotron Analysis of Thermal Barrier Coatings under Thermal Gradients and Mechanical LoadsPascal Fouquet1, Frank Ramirez1, Stephen Sofronsky1, Albert Manero1, Kevin Knipe1, Carla Meid3, Janine Wischek3,
John Okasinski2, Jonathan Almer2, Marion Bartsch3, and Seetha Raghavan1
Develop techniques to apply thermal gradient and mechanical loading while maintaining access to high energy x-ray measurements
Develop measurement techniques to accurately obtain in-situ X-ray diffraction (XRD) strain measurements of each internal layer of the tubular sample
Determine strain behavior of coating layers under thermal gradient and mechanical loading conditions
ResultsThermal Gradient and Mechanical Single Cycles
Aged samples have a thicker and more developed TGO layer due to repeated cycling
Analyze strains in aged samples to establish quantitative strain relief and observe damage mechanisms
Crack formation in an aged sample, by M. Bartsch et al., 2008
K. Knipe, A. Manero, S. Siddiqui, C. Meid, J. Wischek, J. Okasinski, J. Almer, A. Karlsson, M. Bartsch, and S. Raghavan, Effects of Thermal Gradient and Mechanical Loading on In-Cycle Strains for Thermal Barrier Coatings Determined through Synchrotron XRD Measurements , (In Review)
M. Bartsch, B. Baufeld, S. Dalkiliç, L. Chernova, M. Heinzelmann, Fatigue cracks in a thermal barrier coating system on a superalloy in multiaxial thermomechanical testing International Journal of Fatigue, 30(2008), p. 211
S. Siddiqui, K. Knipe, A. Manero, C. Meid, J. Wischek, J. Okasinski, J. Almer, J. Schneider, M. Bartsch, S. Raghavan, Synchrotron X-ray Measurement Techniques for Thermal Barrier Coated Cylindrical Samples Rev Sci Instrum, 84(2013), p. 8
There is an increasing need to extend the operational temperature limits of turbine components. Thermal barrier coatings combined with internal substrate cooling allow for operating temperatures exceeding the melting temperatures of the turbine substrate. The thermal expansion mismatch between the different materials however, result in large residual stresses that are linked to failure. In-situ synchrotron diffraction provides the means to establish the evolution of strain at high resolution.
The X-rays diffract onto a high resolution 2-D detector in the form of distorted rings
The elliptical state of the ring is indicative of strain
X-Ray Scan Through Coating Thickness
Window Size 30 x 300 microns
10 Window Scan
BC YSZ
Exhaust Air
Co
ntroller
/Co
mp
ute
r
The
rmo
cou
ple
s
Flow ControllerCoolant: Compressed Air
X-ray Beam
Heat toSample
Coolant
Experimental DiagramMTS
MTS
This material is based upon work supported by the National Science Foundation grants (Grant Nos. OISE 1157619 and CMMI 1125696) and by the German Science Foundation (DFG) grant (Grant No. SFB-TRR103), Project A3
Use of the Advanced Photon Source at Argonne National Laboratory was supported by the U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences, under Contract No. DE-AC02-06CH11357
1.6 1.8 2 2.2 2.4 2.6 2.8 3 3.2
0
2
4
6
8
10
Plot of d spacing vs intensity of material peaks scanned with the highlighted section showing the thermal expansion of the bond coat due to the increasing thermal gradient
Loading Conditions
A) At room temperature, YSZ expresses compressive in-plane strain (e22)
B) The bond coat expresses tensile in-plane strain (e22) As the surface temperature is ramped up to high
temperature, both layers then relaxes to zero strain
A)
A) When strain is induced on a lattice structure, the diffraction angle is altered due to Bragg s Law
B) The change in diffraction angle results in an elliptical distortion of the diffraction ring
C) Identifying the zero strain reference angle
D) Bond coat strain results at an individual measurement for the experiment with a 128Mpa load and 40 liters/min flow rate
The thermal barrier coating (TBC) is adhered to the surface of the turbine blade by a nickel based bond coat and the blade is forced cooled with air by an internal coolant channel.
Experiment in progress
Variations in Thermal Gradients
With increasing thermal gradient, the YSZ demonstrates minimal change in strain from the outer surface into the middle of the layer
The inner region of the YSZ displays a significantly increasing compressive strain and thus higher strain gradient
Inner YSZ Radius Outer YSZ Radius
YSZ (111) e22 strain displayed the YSZ thickness at various thermal gradients
Variations in Mechanical Load
Strain relationships of YSZ and bond coat with respect to axial load at various temperatures
The YSZ and NiAl in the bond coat gradually bear less of the applied load as temperature increases
Inelastic behavior is experienced in the bond coat above 800oC, as is displayed by the flat strain response to mechanical load
Loading Conditions
The experiment was conducted at Argonne National Laboratory
Orientation of e22 and e11 with respect to the sample
A)
B)
2-D Unstrained Ring2-D Strained Ring
Azimuthal Angle
Zero Strain Reference Angle
B)
C)
Azimuthal Angle50 100 150 200 250 300 350
511.5
512
512.5
513
513.5
514
514.5
Radia
l P
ositi
on (
Pix
els
)
Increasing
Load
Ro
η*
Sample IN 100 Substrate
Outside Diameter = 8mmInside Diameter = 4mm
NiCoCrAlY Bond Coat80 µm EB-PVD Coating
α-Al2O3 Oxide Layer (TGO)As-Coated 0.5 µm Thickness
Yttria Stabilized Zirconia (YSZ)EB-PVD 240 µm Coating
Cylindrical sample manufactured at DLR
Pratt and Whitney F-119 engine
Lockheed Martin F-22 Raptor
Turbine Blade metal alloy
Bond Coat
TGO
TBC
Combustion gases
Tem
per
atu
re
Displacement
Operating Temperature
Blade Melting point
Cross Section of Turbine Blade
Coolant Channel
D)
Bond CoatYSZ
45 90 135 180 225 270 315
-5
0
5
10
x 10-4
Dif
frac
tion
Str
ain
(R
o-R
)/R
o ε22
ε11
η*
Azimuthal Angle
