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NSYSU
1.
Wang , Jhao-Shun.
Analysis of Residual Stress Distribution in ITO Thin Film Coated on Si-Substrate by Applying DIC Technique and Taguchi Method.
Degree: Master, Mechanical and Electro-Mechanical Engineering, 2016, NSYSU
URL: http://etd.lib.nsysu.edu.tw/ETD-db/ETD-search/view_etd?URN=etd-0718116-153028 
► In the MEMS process, a thin film is likely to be coated on a substrate. Residual stress is established in the coating upon cooling to…
(more)
▼ In the MEMS process, a thin film is likely to be coated on a substrate.
Residual stress is established in the
coating upon cooling to room temperature because thermal expansion coefficients of the thin film and the substrate are different. The
residual stress in the
coating not only causes bending but also affects the quality of
coating. This thesis discusses the relationship of the
residual stress and its distribution with the parameters of the process and the thickness of the ITO thin film that is coated on the Si-substrate.
Four parameters of
coating process -
coating time, sputtering power, working pressure, and argon flow rate â are considered here. In the experiment, each parameter is set to one of three levels, consistent with the Taguchi Method, yielding nine combinations. For each of the nine combinations, three Si-substrates are used. Measurements are made at nine points on each Si-substrate. Two sets of the in-plane displacement of the
coating from two different angles of the screen can be measured by using digital image correlation technique. The obtained sets of in-plane displacements can be used to calculate the out-of-plane displacement, the components of
residual stress in the x-direction and the y-direction can be calculated using the modified Stoneyâs equation. The equivalent
residual stress is calculated from these components of
residual stresses, and the coefficient of variation is calculated from the average and standard deviation of the equivalent
residual stress at the nine points on the Si-substrate. Finally, the distribution of
residual stress in
coating is discussed with reference to the experimentally obtained coefficient of variation.
The experimental results indicate that the
coating time and the sputtering power importantly affect the magnitude of
residual stress, but the working pressure and the argon flow rate have very little effect. Additionally, the experimental results show that the
residual stress distribution is affected by
coating time, sputtering power, argon flow rate and working pressure, in order of declining strength of the effect. The
coating time most strongly affects the
coating process. As the
coating thickness increases, the
residual stress decreases and the variation among measurements made of three Si-substrates of same combination declines. Restated, the precision of the experimental measurements improves with the
coating thickness, but the distribution of
residual stress becomes less uniform.
Advisors/Committee Members: T. N. Shiau (chair), Jung-Hung Sun (chair), Chung-Ting Wang (chair), Chi-Hui Chien (committee member).
Subjects/Keywords: Digital Image Correlation Method; Indium Tin Oxide Film; Taguchi Method; Coating Residual Stress; Coating Distribution
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APA (6th Edition):
Wang , J. (2016). Analysis of Residual Stress Distribution in ITO Thin Film Coated on Si-Substrate by Applying DIC Technique and Taguchi Method. (Thesis). NSYSU. Retrieved from http://etd.lib.nsysu.edu.tw/ETD-db/ETD-search/view_etd?URN=etd-0718116-153028
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
Chicago Manual of Style (16th Edition):
Wang , Jhao-Shun. “Analysis of Residual Stress Distribution in ITO Thin Film Coated on Si-Substrate by Applying DIC Technique and Taguchi Method.” 2016. Thesis, NSYSU. Accessed February 26, 2021.
http://etd.lib.nsysu.edu.tw/ETD-db/ETD-search/view_etd?URN=etd-0718116-153028.
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
MLA Handbook (7th Edition):
Wang , Jhao-Shun. “Analysis of Residual Stress Distribution in ITO Thin Film Coated on Si-Substrate by Applying DIC Technique and Taguchi Method.” 2016. Web. 26 Feb 2021.
Vancouver:
Wang J. Analysis of Residual Stress Distribution in ITO Thin Film Coated on Si-Substrate by Applying DIC Technique and Taguchi Method. [Internet] [Thesis]. NSYSU; 2016. [cited 2021 Feb 26].
Available from: http://etd.lib.nsysu.edu.tw/ETD-db/ETD-search/view_etd?URN=etd-0718116-153028.
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
Council of Science Editors:
Wang J. Analysis of Residual Stress Distribution in ITO Thin Film Coated on Si-Substrate by Applying DIC Technique and Taguchi Method. [Thesis]. NSYSU; 2016. Available from: http://etd.lib.nsysu.edu.tw/ETD-db/ETD-search/view_etd?URN=etd-0718116-153028
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
NSYSU
2.
Gan, Jia-lun.
Measurement of the Residual Stress in Cr-Film by Using DIC.
Degree: Master, Mechanical and Electro-Mechanical Engineering, 2015, NSYSU
URL: http://etd.lib.nsysu.edu.tw/ETD-db/ETD-search/view_etd?URN=etd-0725115-143720
► In the past, if a researcher intended to measure the residual stress in a thin film coated on a substrate, the Stoney's equation was adopted…
(more)
▼ In the past, if a researcher intended to measure the
residual stress in a thin film coated on a substrate, the Stoney's equation was adopted and assumed that the
residual stresses on the interface between film and substrate were distributed uniformity. The purpose of this thesis was to discuss the flexibility of previously mentioned uniformly distributed
residual stresses assumption by investigating the distribution of
residual stresses in different thickness of Cr film coated on a silicon substrate. Also, the relationship between the film thickness and the magnitude and distribution of
residual stresses were studied. Firstly, a specific thickness of Cr film was coated on a cantilever beam made of silicon. Then, the
residual stress can be calculated by using modified Stoney's equation and the measured out-of-plane deformation of the cantilever beam which were caused by film
residual stresses. The out-of-plane deformation were measured by using digital image correlation technique with single CCD only. This thesis explored three
coating thicknesses, which were 1 μm, 2 μm and 3 μm, respectively, and there were three specimens corresponded to each thickness. In order to investigate the distribution of
residual stresses, the
residual stresses at nine different test points on each specimen were determined. The results showed a trend that the magnitude of
residual stress decreased with increasing film thickness. By combining the experimental results and statistical theory showed that the reliability of the magnitude of
residual stress corresponding to 3 μm film thickness smaller than 1 μm film thickness was 86.5%. The results also showed that the
residual stresses were distributed non-uniformity. The reliability of the
residual stresses corresponding to 1 μm film thickness distributed more non-uniform than 3 μm film thickness was 70.98%.
Advisors/Committee Members: Ting Nung Shiau (chair), Chi-Hui Chien (committee member), Jung-Hung Sun (chair).
Subjects/Keywords: digital image correlation; film thickness; residual stress; coating film; cantilever beam
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APA (6th Edition):
Gan, J. (2015). Measurement of the Residual Stress in Cr-Film by Using DIC. (Thesis). NSYSU. Retrieved from http://etd.lib.nsysu.edu.tw/ETD-db/ETD-search/view_etd?URN=etd-0725115-143720
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
Chicago Manual of Style (16th Edition):
Gan, Jia-lun. “Measurement of the Residual Stress in Cr-Film by Using DIC.” 2015. Thesis, NSYSU. Accessed February 26, 2021.
http://etd.lib.nsysu.edu.tw/ETD-db/ETD-search/view_etd?URN=etd-0725115-143720.
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
MLA Handbook (7th Edition):
Gan, Jia-lun. “Measurement of the Residual Stress in Cr-Film by Using DIC.” 2015. Web. 26 Feb 2021.
Vancouver:
Gan J. Measurement of the Residual Stress in Cr-Film by Using DIC. [Internet] [Thesis]. NSYSU; 2015. [cited 2021 Feb 26].
Available from: http://etd.lib.nsysu.edu.tw/ETD-db/ETD-search/view_etd?URN=etd-0725115-143720.
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
Council of Science Editors:
Gan J. Measurement of the Residual Stress in Cr-Film by Using DIC. [Thesis]. NSYSU; 2015. Available from: http://etd.lib.nsysu.edu.tw/ETD-db/ETD-search/view_etd?URN=etd-0725115-143720
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
University of Central Florida
3.
Knipe, Kevin.
In-situ synchrotron studies of turbine blade thermal barrier coatings under extreme environments.
Degree: 2014, University of Central Florida
URL: https://stars.library.ucf.edu/etd/1272
► Thermal Barrier Coatings have been used for decades to impose a thermal gradient between the hot combustion gases and the underlying superalloy substrate in engine…
(more)
▼ Thermal Barrier Coatings have been used for decades to impose a thermal gradient between the hot combustion gases and the underlying superalloy substrate in engine turbine blades. Yttria Stabilized Zirconia (YSZ) is an industry standard high temperature ceramic for turbine applications. The protective
coating is adhered to the substrate using a nickel based alloy bond coat. Through exposure to high temperature, a Thermally Grown Oxide (TGO) layer develops at the bond coat-YSZ interface. Large
residual stresses develop in these layers due to thermal expansion mismatch that occurs during cool down from high temperature spraying and cyclic operating conditions. Despite their standard use, much is to be determined as to how these
residual stresses are linked to the various failure modes. This study developed techniques to monitor the strain and
stress in these internal layers during thermal gradient and mechanical conditions representing operating conditions. The thermal gradient is applied across the
coating thickness of the tubular samples from infrared heating of the outer
coating and forced air internal cooling of the substrate. While thermal and mechanical loading conditions are applied, 2-dimensional diffraction measurements are taken using the high-energy Synchrotron X-Rays and analyzed to provide high-resolution depth-resolved strain. This study will include fatigue comparisons through use of samples, which are both 'as-coated' as well as aged to various stages in a TBC lifespan. Studies reveal that variations in thermal gradients and mechanical loads create corresponding trends in depth resolved strains with the largest effects displayed at or near the bond coat/TBC interface. Single cycles as well as experiments targeting thermal gradient and mechanical effects were conducted to capture these trends. Inelastic behavior such as creep was observed and quantified for the different layers at high temperatures. From these studies more accurate lifespan predictions, material behaviors, and causes of failure modes can be determined. The work further develops measurement and analysis techniques for diffraction measurements in internal layers on a coated tubular sample which can be used by various industries to analyze similar geometries with different applications.
Advisors/Committee Members: Raghavan, Seetha.
Subjects/Keywords: Tbc; thermal barrier coating; x ray diffraction; synchrotron; residual stress; tgmf; Engineering; Mechanical Engineering
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APA (6th Edition):
Knipe, K. (2014). In-situ synchrotron studies of turbine blade thermal barrier coatings under extreme environments. (Doctoral Dissertation). University of Central Florida. Retrieved from https://stars.library.ucf.edu/etd/1272
Chicago Manual of Style (16th Edition):
Knipe, Kevin. “In-situ synchrotron studies of turbine blade thermal barrier coatings under extreme environments.” 2014. Doctoral Dissertation, University of Central Florida. Accessed February 26, 2021.
https://stars.library.ucf.edu/etd/1272.
MLA Handbook (7th Edition):
Knipe, Kevin. “In-situ synchrotron studies of turbine blade thermal barrier coatings under extreme environments.” 2014. Web. 26 Feb 2021.
Vancouver:
Knipe K. In-situ synchrotron studies of turbine blade thermal barrier coatings under extreme environments. [Internet] [Doctoral dissertation]. University of Central Florida; 2014. [cited 2021 Feb 26].
Available from: https://stars.library.ucf.edu/etd/1272.
Council of Science Editors:
Knipe K. In-situ synchrotron studies of turbine blade thermal barrier coatings under extreme environments. [Doctoral Dissertation]. University of Central Florida; 2014. Available from: https://stars.library.ucf.edu/etd/1272
4.
Guinard, Caroline.
Influence des propriétés morphologiques et mécaniques des barrières thermiques sur la fissuration interfaciale induite par perçage laser impulsionnel : Influence of morphological and mechanical properties of thermal barrier coating on interfacial delamination induced by impulsionnal laser drilling.
Degree: Docteur es, Sciences et génie des matériaux, 2016, Paris Sciences et Lettres (ComUE)
URL: http://www.theses.fr/2016PSLEM068
► De nombreuses pièces aéronautiques telles que les chambres de combustion sont percées d'une multitudes de trous de refroidissement. Ce perçage, généralement effectué par un laser…
(more)
▼ De nombreuses pièces aéronautiques telles que les chambres de combustion sont percées d'une multitudes de trous de refroidissement. Ce perçage, généralement effectué par un laser de puissance peut induire des endommagements dans la matière percée. Sur les systèmes barrières thermiques, une fissuration pouvant conduire à l'écaillage de la barrière thermique se produit à l'interface céramique/sous-couche lors du perçage laser. Cette thèse présente des éléments de compréhension des phénomènes de formation et de propagation de la fissure interfaciale. Pour cela, un protocole spécifique a été utilisé, consistant en la réalisation de perçage interrompus. De plus, afin de comprendre l'influence de la sous-couche et de l'interface sous-couche / céramique sur cette fissuration, une large gamme d'échantillons aux propriétés morphologiques et mécaniques bien distincts ont été sélectionnés. Pour cela, la sous-couche a été modifiée par la variation des paramètres de projection, du procédé de projection ainsi que par des post traitements sur la sous-couche. Le lien entre ces interfaces et les endommagements liés au perçage laser sont présentés au travers d'observations 2D et 3D, destructives et non destructives ainsi que par l'étude des modifications des contraintes résiduelles avant et après perçage laser pour différentes barrières thermiques. De manière a réduire encore la fissure interfaciale, plusieurs stratégies de perçage sont étudiées via la variation de la puissance laser entre les différentes impulsions laser nécessaires pour percer le matériau multicouches. Les résultats obtenus offrent des perspectives intéressantes pour améliorer la résistance à la fissuration des pièces aéronautiques.
Many aircraft engines parts such as combustion chambers are drilled with numerous cooling holes. These holes, generally performed by a high power laser machine can induce damages in the part materials. On thermal barrier coatings systems, cracking can lead to spalling of the coating occurs at the ceramic / bond-coat layer interface during laser drilling. This thesis presents elements of understanding of the interfacial crack formation end propagation phenomena. In this purpose, a specific protocol was used, consisting of interrupted drilling process. Moreover, in order to understand the influence of the bond coat and the ceramic / bond coat interface on cracking, a wide range of samples with specific morphological and mechanical properties were selected. With this in mind, the bond coat was modified by varying spraying parameters, spraying process and also by post treatments on the bond coat. The link between these interfaces and the associated damages due to laser drilling are presented through 2D and 3D observations, destructive and non-destructive, as well as the study of residual stress modification before and after laser drilling for several thermal barrier coatings systems. For further reducing the interfacial crack, several drilling strategies are considered through the laser peak power variation between the different laser…
Advisors/Committee Members: Guipont, Vincent (thesis director).
Subjects/Keywords: Barrières thermiques; Plasma; Perçage laser; Fissuration; Laminographie; Contraintes résiduelles; Thermal barrier coating; Plasma spray; Laser drilling; Cracking; Laminographie; Residual stress; 620.11
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APA ·
Chicago ·
MLA ·
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CSE |
Export
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Manager
APA (6th Edition):
Guinard, C. (2016). Influence des propriétés morphologiques et mécaniques des barrières thermiques sur la fissuration interfaciale induite par perçage laser impulsionnel : Influence of morphological and mechanical properties of thermal barrier coating on interfacial delamination induced by impulsionnal laser drilling. (Doctoral Dissertation). Paris Sciences et Lettres (ComUE). Retrieved from http://www.theses.fr/2016PSLEM068
Chicago Manual of Style (16th Edition):
Guinard, Caroline. “Influence des propriétés morphologiques et mécaniques des barrières thermiques sur la fissuration interfaciale induite par perçage laser impulsionnel : Influence of morphological and mechanical properties of thermal barrier coating on interfacial delamination induced by impulsionnal laser drilling.” 2016. Doctoral Dissertation, Paris Sciences et Lettres (ComUE). Accessed February 26, 2021.
http://www.theses.fr/2016PSLEM068.
MLA Handbook (7th Edition):
Guinard, Caroline. “Influence des propriétés morphologiques et mécaniques des barrières thermiques sur la fissuration interfaciale induite par perçage laser impulsionnel : Influence of morphological and mechanical properties of thermal barrier coating on interfacial delamination induced by impulsionnal laser drilling.” 2016. Web. 26 Feb 2021.
Vancouver:
Guinard C. Influence des propriétés morphologiques et mécaniques des barrières thermiques sur la fissuration interfaciale induite par perçage laser impulsionnel : Influence of morphological and mechanical properties of thermal barrier coating on interfacial delamination induced by impulsionnal laser drilling. [Internet] [Doctoral dissertation]. Paris Sciences et Lettres (ComUE); 2016. [cited 2021 Feb 26].
Available from: http://www.theses.fr/2016PSLEM068.
Council of Science Editors:
Guinard C. Influence des propriétés morphologiques et mécaniques des barrières thermiques sur la fissuration interfaciale induite par perçage laser impulsionnel : Influence of morphological and mechanical properties of thermal barrier coating on interfacial delamination induced by impulsionnal laser drilling. [Doctoral Dissertation]. Paris Sciences et Lettres (ComUE); 2016. Available from: http://www.theses.fr/2016PSLEM068
5.
Li, Chun.
Measurement and Understanding the Residual Stress
Distribution as a Function of Depth in Atmosphere Plasma Sprayed
Thermal Barrier Coatings.
Degree: 2017, University of Manchester
URL: http://www.manchester.ac.uk/escholar/uk-ac-man-scw:310892
► Residual stresses are generally considered to be the driving forces for the failure of APS TBCs. In this thesis, the residual stress distribution as a…
(more)
▼ Residual stresses are generally considered to be
the driving forces for the failure of APS TBCs. In this thesis, the
residual stress distribution as a function of depth in APS TBC has
been measured by synchrotron XRD and explained by image based
modelling based on the microstructure detailed studied by SEM and
CT. The
residual stress/ strain distribution as a function of depth
was measured by synchrotron XRD in transmission and reflection
geometry. The
residual stress/ strain values were analysed using
full pattern Rietveld refinement, the sin square psi method and
XRD2 method. For the reflection geometry, a new method was
developed to deconvolute the
residual stress value in each depth
from the measured averaged values. Two types of
residual
stress/strain distribution were observed. The first kind of
residual stress was found to be compressive and followed a
non-linear trend, which increased from the surface to the
interface, decreased slightly and increased again to the interface.
This trend showed a jump feature near the interface. The second
kind of
residual stress distribution possessed two jump features:
one near the interface similar to the first kind and another jump
feature near the sample surface. The
residual stress in both beta
and gama phase in the bond coat were also investigated which showed
a tensile
stress state. The
stress trend predicted by our
analytical model followed a linear relationship. Comparing this
with the first kind of
residual stress distribution, two main
differences were shown. Firstly the jump feature near the interface
and secondly the much larger overall
stress gradient. The 3D and 2D
microstructure of the sample with the first kind of
residual stress
distribution was observed by X-ray CT and SEM. The effect of pores,
inter-splat cracks and the rumpling interface on the
residual
stress distribution was investigated by image based modelling. It
was proved that the pores and the inter-splat cracks had no large
influence on the
stress distribution and the jump feature near the
interface was a result of the rumpling interface. The much larger
stress gradient observed in the measured
residual stress
distribution was an indication of the
stress relaxation in the
coating which was proved by a specially designed mechanical test.
To explain the jump feature near the sample surface in the second
kind of
stress distribution. 3D microstructures of the measured
samples were observed using X-ray CT. The effect of vertical and
the side cracks on the
stress distribution were investigated by
image based modelling. It was found that the vertical crack had no
large influence on the
residual stress distribution and the jump
feature in the
stress trend near the surface could be attributed to
the side crack. The effect of other kinds of cracks that were not
directly observed in our samples, such as middle or through side
cracks, were also investigated. These results were used to develop
a semi-destructive method to determine the existence and
distribution of cracks in APS TBC
Advisors/Committee Members: XIAO, PING P, Cernik, Robert, Xiao, Ping.
Subjects/Keywords: Thermal Barrier Coating; Residual Stress; Synchrotron XRD; Computed Tomography; Image Based Modelling; Digital Image Correlation
…residual stress
distribution was an indication of the stress relaxation in the coating which was… …coating: top coat and bond coat, the failure phenomenon of APS TBC,
residual stress measurement… …residual stress and deconvoluted residual stress
distribution in the TBC as a function of depth… …surface to the interface. The deconvoluted
residual stress shows a similar trend to the average… …schematic picture of the geometry of the residual stress measurement by
synchrotron XRD. At the…
Record Details
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Record Details
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❌
APA ·
Chicago ·
MLA ·
Vancouver ·
CSE |
Export
to Zotero / EndNote / Reference
Manager
APA (6th Edition):
Li, C. (2017). Measurement and Understanding the Residual Stress
Distribution as a Function of Depth in Atmosphere Plasma Sprayed
Thermal Barrier Coatings. (Doctoral Dissertation). University of Manchester. Retrieved from http://www.manchester.ac.uk/escholar/uk-ac-man-scw:310892
Chicago Manual of Style (16th Edition):
Li, Chun. “Measurement and Understanding the Residual Stress
Distribution as a Function of Depth in Atmosphere Plasma Sprayed
Thermal Barrier Coatings.” 2017. Doctoral Dissertation, University of Manchester. Accessed February 26, 2021.
http://www.manchester.ac.uk/escholar/uk-ac-man-scw:310892.
MLA Handbook (7th Edition):
Li, Chun. “Measurement and Understanding the Residual Stress
Distribution as a Function of Depth in Atmosphere Plasma Sprayed
Thermal Barrier Coatings.” 2017. Web. 26 Feb 2021.
Vancouver:
Li C. Measurement and Understanding the Residual Stress
Distribution as a Function of Depth in Atmosphere Plasma Sprayed
Thermal Barrier Coatings. [Internet] [Doctoral dissertation]. University of Manchester; 2017. [cited 2021 Feb 26].
Available from: http://www.manchester.ac.uk/escholar/uk-ac-man-scw:310892.
Council of Science Editors:
Li C. Measurement and Understanding the Residual Stress
Distribution as a Function of Depth in Atmosphere Plasma Sprayed
Thermal Barrier Coatings. [Doctoral Dissertation]. University of Manchester; 2017. Available from: http://www.manchester.ac.uk/escholar/uk-ac-man-scw:310892
6.
Li, Chun.
Measurement and understanding the residual stress distribution as a function of depth in atmosphere plasma sprayed thermal barrier coatings.
Degree: PhD, 2018, University of Manchester
URL: https://www.research.manchester.ac.uk/portal/en/theses/measurement-and-understanding-the-residual-stress-distribution-as-a-function-of-depth-in-atmosphere-plasma-sprayed-thermal-barrier-coatings(e4dd38cc-2800-4719-bfe5-cccd0d6ff8c8).html
;
https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.724667
► Residual stresses are generally considered to be the driving forces for the failure of APS TBCs. In this thesis, the residual stress distribution as a…
(more)
▼ Residual stresses are generally considered to be the driving forces for the failure of APS TBCs. In this thesis, the residual stress distribution as a function of depth in APS TBC has been measured by synchrotron XRD and explained by image based modelling based on the microstructure detailed studied by SEM and CT. The residual stress/ strain distribution as a function of depth was measured by synchrotron XRD in transmission and reflection geometry. The residual stress/ strain values were analysed using full pattern Rietveld refinement, the sin square psi method and XRD2 method. For the reflection geometry, a new method was developed to deconvolute the residual stress value in each depth from the measured averaged values. Two types of residual stress/strain distribution were observed. The first kind of residual stress was found to be compressive and followed a non-linear trend, which increased from the surface to the interface, decreased slightly and increased again to the interface. This trend showed a jump feature near the interface. The second kind of residual stress distribution possessed two jump features: one near the interface similar to the first kind and another jump feature near the sample surface. The residual stress in both beta and gama phase in the bond coat were also investigated which showed a tensile stress state. The stress trend predicted by our analytical model followed a linear relationship. Comparing this with the first kind of residual stress distribution, two main differences were shown. Firstly the jump feature near the interface and secondly the much larger overall stress gradient. The 3D and 2D microstructure of the sample with the first kind of residual stress distribution was observed by X-ray CT and SEM. The effect of pores, inter-splat cracks and the rumpling interface on the residual stress distribution was investigated by image based modelling. It was proved that the pores and the inter-splat cracks had no large influence on the stress distribution and the jump feature near the interface was a result of the rumpling interface. The much larger stress gradient observed in the measured residual stress distribution was an indication of the stress relaxation in the coating which was proved by a specially designed mechanical test. To explain the jump feature near the sample surface in the second kind of stress distribution. 3D microstructures of the measured samples were observed using X-ray CT. The effect of vertical and the side cracks on the stress distribution were investigated by image based modelling. It was found that the vertical crack had no large influence on the residual stress distribution and the jump feature in the stress trend near the surface could be attributed to the side crack. The effect of other kinds of cracks that were not directly observed in our samples, such as middle or through side cracks, were also investigated. These results were used to develop a semi-destructive method to determine the existence and distribution of cracks in APS TBC.
Subjects/Keywords: 620.1; Thermal Barrier Coating; Residual Stress; Synchrotron XRD; Computed Tomography; Image Based Modelling; Digital Image Correlation
…residual stress
distribution was an indication of the stress relaxation in the coating which was… …coating: top coat and bond coat, the failure phenomenon of APS TBC,
residual stress measurement… …residual stress and deconvoluted residual stress
distribution in the TBC as a function of depth… …surface to the interface. The deconvoluted
residual stress shows a similar trend to the average… …schematic picture of the geometry of the residual stress measurement by
synchrotron XRD. At the…
Record Details
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Record Details
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❌
APA ·
Chicago ·
MLA ·
Vancouver ·
CSE |
Export
to Zotero / EndNote / Reference
Manager
APA (6th Edition):
Li, C. (2018). Measurement and understanding the residual stress distribution as a function of depth in atmosphere plasma sprayed thermal barrier coatings. (Doctoral Dissertation). University of Manchester. Retrieved from https://www.research.manchester.ac.uk/portal/en/theses/measurement-and-understanding-the-residual-stress-distribution-as-a-function-of-depth-in-atmosphere-plasma-sprayed-thermal-barrier-coatings(e4dd38cc-2800-4719-bfe5-cccd0d6ff8c8).html ; https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.724667
Chicago Manual of Style (16th Edition):
Li, Chun. “Measurement and understanding the residual stress distribution as a function of depth in atmosphere plasma sprayed thermal barrier coatings.” 2018. Doctoral Dissertation, University of Manchester. Accessed February 26, 2021.
https://www.research.manchester.ac.uk/portal/en/theses/measurement-and-understanding-the-residual-stress-distribution-as-a-function-of-depth-in-atmosphere-plasma-sprayed-thermal-barrier-coatings(e4dd38cc-2800-4719-bfe5-cccd0d6ff8c8).html ; https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.724667.
MLA Handbook (7th Edition):
Li, Chun. “Measurement and understanding the residual stress distribution as a function of depth in atmosphere plasma sprayed thermal barrier coatings.” 2018. Web. 26 Feb 2021.
Vancouver:
Li C. Measurement and understanding the residual stress distribution as a function of depth in atmosphere plasma sprayed thermal barrier coatings. [Internet] [Doctoral dissertation]. University of Manchester; 2018. [cited 2021 Feb 26].
Available from: https://www.research.manchester.ac.uk/portal/en/theses/measurement-and-understanding-the-residual-stress-distribution-as-a-function-of-depth-in-atmosphere-plasma-sprayed-thermal-barrier-coatings(e4dd38cc-2800-4719-bfe5-cccd0d6ff8c8).html ; https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.724667.
Council of Science Editors:
Li C. Measurement and understanding the residual stress distribution as a function of depth in atmosphere plasma sprayed thermal barrier coatings. [Doctoral Dissertation]. University of Manchester; 2018. Available from: https://www.research.manchester.ac.uk/portal/en/theses/measurement-and-understanding-the-residual-stress-distribution-as-a-function-of-depth-in-atmosphere-plasma-sprayed-thermal-barrier-coatings(e4dd38cc-2800-4719-bfe5-cccd0d6ff8c8).html ; https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.724667
University of Toronto
7.
Samadi, Hamed.
A Thick Multilayer Thermal Barrier Coating: Design, Deposition, and Internal Stresses.
Degree: 2009, University of Toronto
URL: http://hdl.handle.net/1807/19086
► Yttria Partially Stabilized Zirconia (Y-PSZ) plasma-sprayed coatings are widely used in turbine engines as thermal barrier coatings. However, in diesel engines Y-PSZ TBCs have not…
(more)
▼ Yttria Partially Stabilized Zirconia (Y-PSZ) plasma-sprayed coatings are widely used in turbine engines as thermal barrier coatings. However, in diesel engines Y-PSZ TBCs have not met with wide success. To reach the desirable temperature of 850-900˚C in the combustion chamber from the current temperature of 400-600˚C, a coating with a thickness of approximately 1mm is required. This introduces different considerations than in the case of turbine blade coatings, which are on the order of 100µm thick. Of the many factors affecting the durability and failure mechanism of TBCs, in service and residual stresses play an especially important role as the thickness of the coating increases. For decreasing the residual stress in the system, a multi-layer coating is helpful. The design of a multilayer coating employing relatively low cost materials with complementary thermal properties is described. Numerical models were used to describe the residual stress after deposition and under operating conditions for a multilayer coating that exhibited the desired temperature gradient. Results showed that the multilayer coating had a lower maximum stress under service conditions than a conventional Y-PSZ coating. Model validation with experiments showed a good match between the two.
PhD
Advisors/Committee Members: Coyle, Thomas W., Materials Science and Engineering.
Subjects/Keywords: Plasma sprayed coatings; ceramics; oxide; thermal barrier coating; residual stress; mullite; spinel; forsterite; 0794
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APA (6th Edition):
Samadi, H. (2009). A Thick Multilayer Thermal Barrier Coating: Design, Deposition, and Internal Stresses. (Doctoral Dissertation). University of Toronto. Retrieved from http://hdl.handle.net/1807/19086
Chicago Manual of Style (16th Edition):
Samadi, Hamed. “A Thick Multilayer Thermal Barrier Coating: Design, Deposition, and Internal Stresses.” 2009. Doctoral Dissertation, University of Toronto. Accessed February 26, 2021.
http://hdl.handle.net/1807/19086.
MLA Handbook (7th Edition):
Samadi, Hamed. “A Thick Multilayer Thermal Barrier Coating: Design, Deposition, and Internal Stresses.” 2009. Web. 26 Feb 2021.
Vancouver:
Samadi H. A Thick Multilayer Thermal Barrier Coating: Design, Deposition, and Internal Stresses. [Internet] [Doctoral dissertation]. University of Toronto; 2009. [cited 2021 Feb 26].
Available from: http://hdl.handle.net/1807/19086.
Council of Science Editors:
Samadi H. A Thick Multilayer Thermal Barrier Coating: Design, Deposition, and Internal Stresses. [Doctoral Dissertation]. University of Toronto; 2009. Available from: http://hdl.handle.net/1807/19086
The Ohio State University
8.
Yen, Yung-Chang.
Modeling of metal cutting and ball burnishing - prediction
of tool wear and surface properties.
Degree: PhD, Industrial and Systems Engineering, 2004, The Ohio State University
URL: http://rave.ohiolink.edu/etdc/view?acc_num=osu1073065455
► The main theme of the proposed research was centered on a broad scope of surface finishing processes, including conventional finish cutting to ball burnishing. In…
(more)
▼ The main theme of the proposed research was centered
on a broad scope of surface finishing processes, including
conventional finish cutting to ball burnishing. In finish cutting,
the effects of edge preparation and tool wear of the cutting tool
are considered most critical, as they directly determine surface
finish and properties of the subsurface layer (
residual stress,
microstructure, microhardness). Understanding of tool wear and the
capability of predicting it enable successful process optimization.
To work towards this goal, the effect of cutting edge designs (hone
and chamfer) on the cutting variables and process mechanics was
investigated using Finite Element Method (FEM) simulations. An
FEM-based methodology involving nodal wear rate calculations was
developed for uncoated carbide to predict the progression of tool
wear geometry during cutting. Cutting inserts with multilayer
coatings are used in every category of industrial cutting
applications. The analysis of the wear behavior of coated tools
largely relies on extensive experimental tests. To supplement
reliable process data and reduce the required experimental costs,
an FEM simulation model for coated tools was developed by modeling
the
coating structure as an effective composite layer. The thermal
insulation effect of the hard coatings (ex. Al2O3) was evaluated
using the model and qualitatively compared with the experimental
data in literature. The developed analysis model for coated tools
was applied to a selected industrial case in which a comparative
study of tool wear was required. The wear characteristics of the
1mm-TiN/9.5mm-Al2O3/4mm-TiCN coated tool against AISI 1080 and 8219
were analyzed through conventional turning experiments.
Correspondingly, an approximated 2-D simulation model was developed
based on fresh tool geometry. This model predicted the initial wear
rate at the start of cutting and allowed differentiation of the
tool wear at distinct cutting conditions. Another focus of this
research was on the surface enhancement by ball burnishing, which
is used following machining to improve surface finish and provide a
surface layer of compressive
residual stresses. The selection of
burnishing pressure, ball diameter, speed, and feed rate needs to
be optimized. A full 3-D FEM analysis model and a simplified 2-D
model were developed and their predictions of
residual stresses
were evaluated with limited experimental data. For the 2-D model,
the strong elastic recovery of the burnished surface during
unloading caused the simulation similar to a series of
“indentions”, whereas the 3-D model showed realistic surface
deformation and material flow. Furthermore, the effects of the
initial plastic strain and
residual stresses in the machined
surface, as opposed to uniform bulk material, were analyzed.
Results showed that they did not have significant effect on the
predicted
residual stresses after burnishing.
Advisors/Committee Members: Altan, Taylan (Advisor).
Subjects/Keywords: Metal cutting; FEM simulation; Edge preparation; Tool wear; Tool coating; Ball burnishing; Surface finish; Residual stress
Record Details
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APA ·
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MLA ·
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CSE |
Export
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Manager
APA (6th Edition):
Yen, Y. (2004). Modeling of metal cutting and ball burnishing - prediction
of tool wear and surface properties. (Doctoral Dissertation). The Ohio State University. Retrieved from http://rave.ohiolink.edu/etdc/view?acc_num=osu1073065455
Chicago Manual of Style (16th Edition):
Yen, Yung-Chang. “Modeling of metal cutting and ball burnishing - prediction
of tool wear and surface properties.” 2004. Doctoral Dissertation, The Ohio State University. Accessed February 26, 2021.
http://rave.ohiolink.edu/etdc/view?acc_num=osu1073065455.
MLA Handbook (7th Edition):
Yen, Yung-Chang. “Modeling of metal cutting and ball burnishing - prediction
of tool wear and surface properties.” 2004. Web. 26 Feb 2021.
Vancouver:
Yen Y. Modeling of metal cutting and ball burnishing - prediction
of tool wear and surface properties. [Internet] [Doctoral dissertation]. The Ohio State University; 2004. [cited 2021 Feb 26].
Available from: http://rave.ohiolink.edu/etdc/view?acc_num=osu1073065455.
Council of Science Editors:
Yen Y. Modeling of metal cutting and ball burnishing - prediction
of tool wear and surface properties. [Doctoral Dissertation]. The Ohio State University; 2004. Available from: http://rave.ohiolink.edu/etdc/view?acc_num=osu1073065455
9.
Tyler, Samson.
Modelling the Effects of Element Doping and Temperature Cycling on the Fracture Toughness of β-NiAl / α-Al2O3 Interfaces in Gas Turbine Engines
.
Degree: 2013, University of Ottawa
URL: http://hdl.handle.net/10393/23685
► This document describes work performed related to the determination of how elemental additions affect the interfacial fracture toughness of thermal barrier coatings at the bond…
(more)
▼ This document describes work performed related to the determination of how elemental additions
affect the interfacial fracture toughness of thermal barrier coatings at the bond coat/thermally grown oxide interface in gas turbines. These turbines are exposed to cyclical thermal loading, therefore a simulation was designed to model this interface in a temperature cycle between 200 K and 1000 K that included oxide growth between 2 μm and 27 μm. The fracture toughness of this interface was then determined to elucidate the function of elemental additions. It was shown that minimal concentrations of atomic species, such as hafnium and yttrium cause notable increases in the toughness of the bond coat/thermally grown oxide interface, while other species, such as sulphur, can dramatically reduce the toughness. Furthermore, it was shown that, contrary to some empirical results, the addition of platinum has a negligible effect on the fracture toughness of this interface.
Subjects/Keywords: Fracture;
Toughness;
Interface;
NiAl;
NiPtAl;
Modelling;
Alumina;
Buckling;
Spallation;
Turbine;
Thermal Barrier Coating;
Doping;
Adhesion;
Residual Stress
…Residual stress measurements; b) α-Al2 O3 signal intensity; c) ratio of α to θ… …61
3.7
Location of residual stress, determined from the previously noted approximation… …residual stress perpendicular to buckled interface [MPa]
σys :
bond coat yield… …residual stress fields, which
alter the global behaviour of these systems. Furthermore, these… …Bibliography
106
viii
List of Figures
1.1
Overview of a thermal barrier coating system on a…
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APA ·
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CSE |
Export
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Manager
APA (6th Edition):
Tyler, S. (2013). Modelling the Effects of Element Doping and Temperature Cycling on the Fracture Toughness of β-NiAl / α-Al2O3 Interfaces in Gas Turbine Engines
. (Thesis). University of Ottawa. Retrieved from http://hdl.handle.net/10393/23685
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
Chicago Manual of Style (16th Edition):
Tyler, Samson. “Modelling the Effects of Element Doping and Temperature Cycling on the Fracture Toughness of β-NiAl / α-Al2O3 Interfaces in Gas Turbine Engines
.” 2013. Thesis, University of Ottawa. Accessed February 26, 2021.
http://hdl.handle.net/10393/23685.
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
MLA Handbook (7th Edition):
Tyler, Samson. “Modelling the Effects of Element Doping and Temperature Cycling on the Fracture Toughness of β-NiAl / α-Al2O3 Interfaces in Gas Turbine Engines
.” 2013. Web. 26 Feb 2021.
Vancouver:
Tyler S. Modelling the Effects of Element Doping and Temperature Cycling on the Fracture Toughness of β-NiAl / α-Al2O3 Interfaces in Gas Turbine Engines
. [Internet] [Thesis]. University of Ottawa; 2013. [cited 2021 Feb 26].
Available from: http://hdl.handle.net/10393/23685.
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
Council of Science Editors:
Tyler S. Modelling the Effects of Element Doping and Temperature Cycling on the Fracture Toughness of β-NiAl / α-Al2O3 Interfaces in Gas Turbine Engines
. [Thesis]. University of Ottawa; 2013. Available from: http://hdl.handle.net/10393/23685
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
Virginia Tech
10.
Guo, Shu.
Experimental and Numerical Investigations on the Durability and Fracture Mechanics of the Bonded Systems for Microelectronics Application.
Degree: PhD, Engineering Science and Mechanics, 2003, Virginia Tech
URL: http://hdl.handle.net/10919/28743
► Water-assisted crack growth at an epoxy/glass interface was measured as a function of applied strain energy release rate, G, and temperature using a wedge test…
(more)
▼ Water-assisted crack growth at an epoxy/glass interface was measured as a function of applied strain energy release rate, G, and temperature using a wedge test geometry. The specimens consist of two glass plates bonded with a thin layer of proprietary epoxy adhesive. The crack fronts along the epoxy/glass interfaces were measured using an optical stereomicroscope. The relationship between G and the debonding rate, v, can be measured using this method, and the threshold value of strain energy release rate, Gth, can be determined from the measured data. Two types of testing procedures were conducted in this study: ex situ, i.e., pre-conditioned wedge tests and in situ ones, in which wedges were applied before the specimens were submerged into water. A preliminary model was developed based on the thermal activation barrier concept, and allows the prediction of Gth for the temperatures beyond the testing region.
Changes in interfacial strain energy release rate caused by thermal
residual stresses in a triple-layered specimen were analyzed in Chapter Three. The method is based on linear elastic fracture mechanics and simple beam theory. The curvature of a bimaterial strip was chosen to characterize the
residual stress in the specimen, and the strain energy release rate, caused by both tensile and compressive
residual stresses in the adhesive, was derived for an asymmetric double cantilever beam (ADCB) geometry. The contribution of the thermal
residual and mechanical
stress to the global energy release rate was analyzed. The thermally induced energy release rate, GT, is found to be independent of crack length, but is a function of
residual stress level and geometric and material parameters of the specimen.
The adhesion of films and coatings to rigid substrates is often measured using blister geometries, which are loaded either by an applied pressure or a central shaft. The measurement will be affected if there are
residual stresses that make a contribution to the energy release rate. This effect is investigated using analytical solutions based on the principle of virtual displacements. A geometrically nonlinear finite element analysis is conducted for comparison. Furthermore, the relationships among strain energy release rate, load, deflection, and fracture radius are discussed in detail in Chapter Four. Both analytical solutions and numerical results reveal that uniform tensile
residual stresses reduce a specimen's deflection if it experiences plate behavior under small loads. However, this effect diminishes when membrane behavior is dominant.
The mechanics of a single-lap joint with different boundary conditions subjected to tensile loading are investigated. Closed-form solutions are obtained for a specimen configuration considering different clamping methods. Based on the approach pioneered by Goland and Reissner, the solutions reported in this paper provide a simple but useful way to understand the effects of boundary conditions on this test geometry. The solutions in this study suggest that different…
Advisors/Committee Members: Dillard, David A. (committeechair), Ward, Thomas C. (committee member), Lesko, John J. (committee member), Batra, Romesh C. (committee member), Dillard, John G. (committee member).
Subjects/Keywords: : thermal residual stresses; stretching; wedge test; spacer.; single-lap joint; diffusion; boundary conditions; clamp; interfacial fracture energy; blister test; simply-supported; bending; subcritical crack growth; temperature; epoxy-glass interface; adhesion; delamination; residual stress; coating; thin film; adhesion; fracture mechanics
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APA ·
Chicago ·
MLA ·
Vancouver ·
CSE |
Export
to Zotero / EndNote / Reference
Manager
APA (6th Edition):
Guo, S. (2003). Experimental and Numerical Investigations on the Durability and Fracture Mechanics of the Bonded Systems for Microelectronics Application. (Doctoral Dissertation). Virginia Tech. Retrieved from http://hdl.handle.net/10919/28743
Chicago Manual of Style (16th Edition):
Guo, Shu. “Experimental and Numerical Investigations on the Durability and Fracture Mechanics of the Bonded Systems for Microelectronics Application.” 2003. Doctoral Dissertation, Virginia Tech. Accessed February 26, 2021.
http://hdl.handle.net/10919/28743.
MLA Handbook (7th Edition):
Guo, Shu. “Experimental and Numerical Investigations on the Durability and Fracture Mechanics of the Bonded Systems for Microelectronics Application.” 2003. Web. 26 Feb 2021.
Vancouver:
Guo S. Experimental and Numerical Investigations on the Durability and Fracture Mechanics of the Bonded Systems for Microelectronics Application. [Internet] [Doctoral dissertation]. Virginia Tech; 2003. [cited 2021 Feb 26].
Available from: http://hdl.handle.net/10919/28743.
Council of Science Editors:
Guo S. Experimental and Numerical Investigations on the Durability and Fracture Mechanics of the Bonded Systems for Microelectronics Application. [Doctoral Dissertation]. Virginia Tech; 2003. Available from: http://hdl.handle.net/10919/28743
. 
Open Access Theses and Dissertations
