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Failure Mechanisms Of Platinum Aluminide Bond Coat Electron Beam Physical Vapor Deposited Thermal Barrier Coatings
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Book Synopsis Failure Mechanisms of Platinum Aluminide Bond Coat/electron Beam-physical Vapor Deposited Thermal Barrier Coatings by : Krishnakumar Vaidyanathan
Download or read book Failure Mechanisms of Platinum Aluminide Bond Coat/electron Beam-physical Vapor Deposited Thermal Barrier Coatings written by Krishnakumar Vaidyanathan and published by . This book was released on 2001 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Thermal barrier coatings (TBCs) allow operation of structural components, such as turbine blades and vanes in industrial and aircraft gas engines, at temperatures close to the substrate melting temperatures. They consist of four different layers; a high strength creep-resistant nickel-based superalloy substrate, an oxidation resistant bond coat (BC), a low thermal conductivity ceramic topcoat and a thermally grown oxide (TGO), that is predominantly α-Al 2O3, that forms between the BC and the TBC. Compressive stresses (3–5 GPa) that are generated in the thin TGO (0.25–8 Î1⁄4m) due to the mismatch in thermal coefficient of expansion between the TGO and BC play a critical role in the failure of these coatings. In this study, the failure mechanisms of a commercial yttria-stabilized zirconia (7YSZ) electron beam-physical vapor deposited (EB-PVD) coating on platinum aluminide (Î2-(Ni,Pt)Al) bond coat have been identified. Two distinct mechanisms have been found responsible for the observed damage initiation and progression at the TGO/bond coat interface. The first mechanism leads to localized debonding at TGO/bond coat interface due to increased out-of-plane tensile stress, along bond coat features that manifest themselves as ridges. The second mechanism causes cavity formation at the TGO/bond coat interface, driven by cyclic plasticity of the bond coat. It has been found that the debonding at the TGO/bond coat interface due to the first mechanism is solely life determining. The final failure occurs by crack extension along either the TGO/bond coat interface or the TGO/YSZ interface or a combination of both, leading to large scale buckling. Based on these mechanisms, it is demonstrated that the bond coat grain size and the aspect ratio of the ridges have a profound influence on spallation lives of the coating. The removal of these ridges by fine polishing prior to TBC deposition led to a four-fold improvement in life. The failure mechanism identified for the improved coatings indicates absence of both the mechanisms that were responsible for damage initiation and progression and hence the final spallation was very different, accounting for the life improvement. The change in compressive residual stress in the TGO layer reflects the damage progression in the TGO layer. To this end, the TGO stresses were measured non-destructively as function of thermal cycles using the novel photoluminescence piezospectroscopy (PLPS) technique. The compressive stresses were found to increase in the first few cycles, (up to 10 cycles) and gradually decrease with increasing number of cycles, up to failure. The standard deviation of the measured stress, indicative of the damage evolution, is found to significantly increase just before the failure of the coating. The sensitivity of the TGO stress to the peak temperature amplitude is also established. Application of the PLPS technique was demonstrated for the first time, both on plasma-sprayed and EB-PVD thermal barrier coated turbine-blades.
Book Synopsis Failure Mechanisms of Platinum Aluminide Bond Coat by : Krishnakumar Vaidyanathan
Download or read book Failure Mechanisms of Platinum Aluminide Bond Coat written by Krishnakumar Vaidyanathan and published by . This book was released on 2001 with total page 612 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis The Effects of Oxidation-Induced Failures on Thermal Barrier Coatings with Platinum Aluminide and NiCoCrAlY Bond Coats by :
Download or read book The Effects of Oxidation-Induced Failures on Thermal Barrier Coatings with Platinum Aluminide and NiCoCrAlY Bond Coats written by and published by . This book was released on 2001 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: This program has been directed at determining the mechanisms by which oxidation causes failure of thermal barrier coatings (TBCs) and developing modified systems with improved resistance to Oxidation-induced failures. The thermal barrier coating was yttria stabilized zirconia (YSZ) deposited via electron beam vapor deposition (EBPVD). This TBC was deposited on both platinum aluminide and NiCoCrA1Y bond coats which in turn were deposited on superalloy substrates of Rare N5. The oxidation testing was performed at 1000 deg, 1100 deg and 1200 deg C in air using cyclic exposures. The approach consisted of initially examining state-of-the-art systems and based upon the results obtained to prepare modified TBCs. Emphasis was placed upon bond coat modifications. In the case of the NiCoCrA1Y bond coats it was found that defects in the as-processed coatings at the TBC-bond coat interface caused failures. Procedures to prevent the formation of such defects extended TBC lives. The lives of TBCs on platinum-aluminide bond coats were influenced by ratcheting of the bond coat at the bond coat-TBC interface. Polishing of bond coats prior to TBC deposition is proposed to inhibit ratcheting and extend TBC lives.
Book Synopsis Failure Mechanisms and Mechanisms-based Life Predictions for Electron Beam Physical Vapor Deposition Thermal Barrier Coatings by : Mei Wen
Download or read book Failure Mechanisms and Mechanisms-based Life Predictions for Electron Beam Physical Vapor Deposition Thermal Barrier Coatings written by Mei Wen and published by . This book was released on 2005 with total page 428 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Investigation of Critical Issues in Thermal Barrier Coating Durability by : Hyungjun Kim
Download or read book Investigation of Critical Issues in Thermal Barrier Coating Durability written by Hyungjun Kim and published by . This book was released on 2005 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Abstract: To more fully understand microstructural evolution and the development of damage in thermal barrier coating (TBC) systems, thermocyclic experiments were conducted on TBC specimens with and without top coats. The degradation of a PtAl (platinum modified aluminide) bond coat and a CMSX superalloy substrate were investigated for cyclic and quasi-isothermal heating to 1200 0C. To accelerate the oxidation of the specimens, the thermally grown oxide (TGO) was removed at 10 hour intervals. Scanning electron microscopy (SEM) and instrumented indentation were employed to investigate microstructural evolution and material property changes of the bond coat. The microstructural evolution of a PtAl bond coat is strongly affected by the type of thermal exposure and the presence of TGO. The differences between cyclic and quasi-isothermal heating indicate that stresses associated with cooling and heating significantly alter microstructural evolution. Damage to TBC specimens with EB-PVD (electron beam physical vapor deposition) processed YSZ (yttria stabilized zirconia) top coats, PtAl bond coats, and René N5 superalloy substrates was assessed during thermal cycling to 1200 0C. Acoustic emission (AE) techniques were used to temporally identify damage to the TBC. For automated, continuous, and high temperature AE detection, a custom made experimental setup with either a nickel-chrome alloy wire wave guide or an alumina wave guide was used. It was found that there are four distinct regions of AE activity during the life of a TBC. Throughout the cooling cycles, images of the top coat were collected with darkfield-type lighting. These images showed how undulations developed in the top coat. In addition, digital image correlation (DIC) was used to identify regions with interfacial damage. Finally, the images were used to analyze the spallation of the top coat. Cycling of an additional specimen was interrupted periodically for analysis with profilometry and SEM. The profilometry and SEM images were used to further investigate the failure mechanisms in TBCs. The experiments and analysis performed in this dissertation work have elucidated how various failure mechanisms develop during the life of TBCs. This work has improved the scientific understanding of TBCs and could aid in the development of improved life prediction models.
Book Synopsis Failure Mechanism Analysis and Life Prediction Based on Atmospheric Plasma-Sprayed and Electron Beam-Physical Vapor Deposition Thermal Barrier Coatings by : Bochun Zhang
Download or read book Failure Mechanism Analysis and Life Prediction Based on Atmospheric Plasma-Sprayed and Electron Beam-Physical Vapor Deposition Thermal Barrier Coatings written by Bochun Zhang and published by . This book was released on 2017 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Using experimentally measured temperature-process-dependent model parameters, the failure analysis and life prediction were conducted for Atmospheric Plasma Sprayed Thermal Barrier Coatings (APS-TBCs) and electron beam physical vapor deposition thermal barrier coatings (EB-PVD TBCs) with Pt-modified -NiAl bond coats deposited on Ni-base single crystal superalloys. For APS-TBC system, a residual stress model for the top coat of APS-TBC was proposed and then applied to life prediction. The capability of the life model was demonstrated using temperature-dependent model parameters. Using existing life data, a comparison of fitting approaches of life model parameters was performed. The role of the residual stresses distributed at each individual coating layer was explored and their interplay on the coating's delamination was analyzed. For EB-PVD TBCs, based on failure mechanism analysis, two newly analytical stress models from the valley position of top coat and ridge of bond coat were proposed describing stress levels generated as consequence of the coefficient of thermal expansion (CTE) mismatch between each layers. The thermal stress within TGO was evaluated based on composite material theory, where effective parameters were calculated. The lifetime prediction of EB-PVD TBCs was conducted given that the failure analysis and life model were applied to two failure modes A and B identified experimentally for thermal cyclic process. The global wavelength related to interface rumpling and its radius curvature were identified as essential parameters in life evaluation, and the life results for failure mode A were verified by existing burner rig test data. For failure mode B, the crack growth rate along the topcoat/TGO interface was calculated using the experimentally measured average interfacial fracture toughness.
Book Synopsis Thermal Barrier Coatings by : Hongbo Guo
Download or read book Thermal Barrier Coatings written by Hongbo Guo and published by Woodhead Publishing. This book was released on 2023-01-18 with total page 490 pages. Available in PDF, EPUB and Kindle. Book excerpt: Thermal Barrier Coatings, Second Edition plays a critical role in counteracting the effects of corrosion and degradation of exposed materials in high-temperature environments such as gas turbine and aero-engines. This updated edition reviews recent advances in the processing and performance of thermal barrier coatings, as well as their failure mechanisms. Novel technologies for the manufacturing of thermal barrier coatings (TBCs) such as plasma spray-physical vapor deposition and suspension plasma spray, are covered, as well as severe degradation of TBCs caused by CMAS attack. In addition to discussions of new materials and technologies, an outlook about next generation TBCs, including T/EBCs is discussed.This edition will provide the fundamental science and engineering of thermal barrier coatings for researchers in the field of TBCs, as well as students looking for a tutorial. Includes coverage of emerging materials, such as rare-earth doped ceramics Presents the latest on plasma spray-physical vapor deposition and suspension (solution precursor) Discusses the degradation of TBCs caused by CMAS attack and its protection Looks at thermally environmental barrier coatings, interdiffusion and diffusion barrier
Download or read book The Superalloys written by Roger C. Reed and published by Cambridge University Press. This book was released on 2008-07-31 with total page 363 pages. Available in PDF, EPUB and Kindle. Book excerpt: Superalloys are unique high-temperature materials used in gas turbine engines, which display excellent resistance to mechanical and chemical degradation. This book introduces the metallurgical principles which have guided their development. Suitable for graduate students and researchers, it includes exercises and additional resources at www.cambridge.org/9780521859042.
Book Synopsis Investigation on the Failure Mechanisms of Electron Beam Physical Vapour Deposited Thermal Barrier Coatings by : Xiaofeng Zhao
Download or read book Investigation on the Failure Mechanisms of Electron Beam Physical Vapour Deposited Thermal Barrier Coatings written by Xiaofeng Zhao and published by . This book was released on 2007 with total page 202 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Progress in Thermal Barrier Coatings by : ACerS (American Ceramics Society, The)
Download or read book Progress in Thermal Barrier Coatings written by ACerS (American Ceramics Society, The) and published by John Wiley & Sons. This book was released on 2009-06-15 with total page 642 pages. Available in PDF, EPUB and Kindle. Book excerpt: This edition of the Progress in Ceramic Technology series compiles articles published on thermal barrier coatings (TBCs) by The American Ceramic Society (ACerS). It collects in one resource the current research papers on materials-related aspects of thermal barrier coatings and associated technologies. Logically organized and carefully selected, the papers in this edition divide into six categories: Applications Material Improvements and Novel Compositions Developments in Processing Mechanical Properties Thermal Properties Citations follow each title in the table of contents, making this a key resource for professionals and academia.
Download or read book Superalloys 2012 written by Eric S. Huron and published by John Wiley & Sons. This book was released on 2012-10-02 with total page 952 pages. Available in PDF, EPUB and Kindle. Book excerpt: A superalloy, or high-performance alloy, is an alloy that exhibits excellent mechanical strength at high temperatures. Superalloy development has been driven primarily by the aerospace and power industries. This compilation of papers from the Twelfth International Symposium on Superalloys, held from September 9-13, 2012, offers the most recent technical information on this class of materials.
Book Synopsis 25th Annual Conference on Composites, Advanced Ceramics, Materials, and Structures - B, Volume 22, Issue 4 by : Mrityunjay Singh
Download or read book 25th Annual Conference on Composites, Advanced Ceramics, Materials, and Structures - B, Volume 22, Issue 4 written by Mrityunjay Singh and published by John Wiley & Sons. This book was released on 2009-09-28 with total page 657 pages. Available in PDF, EPUB and Kindle. Book excerpt: This volume is part of the Ceramic Engineering and Science Proceeding (CESP) series. This series contains a collection of papers dealing with issues in both traditional ceramics (i.e., glass, whitewares, refractories, and porcelain enamel) and advanced ceramics. Topics covered in the area of advanced ceramic include bioceramics, nanomaterials, composites, solid oxide fuel cells, mechanical properties and structural design, advanced ceramic coatings, ceramic armor, porous ceramics, and more.
Book Synopsis ASM Specialty Handbook by : Joseph R. Davis
Download or read book ASM Specialty Handbook written by Joseph R. Davis and published by ASM International. This book was released on 1997-01-01 with total page 608 pages. Available in PDF, EPUB and Kindle. Book excerpt: Materials covered include carbon, alloy and stainless steels; alloy cast irons; high-alloy cast steels; superalloys; titanium and titanium alloys; refractory metals and alloys; nickel-chromium and nickel-thoria alloys; structural intermetallics; structural ceramics, cermets, and cemented carbides; and carbon-composites.
Book Synopsis Damage Accumulation Mechanisms in Thermal Barrier Coatings by : Golam Newaz
Download or read book Damage Accumulation Mechanisms in Thermal Barrier Coatings written by Golam Newaz and published by . This book was released on 1998 with total page 46 pages. Available in PDF, EPUB and Kindle. Book excerpt: The primary focus of the investigation was to conduct a chronological evaluation of damage initiation and propagation in Electron Beam - Physical Vapor Deposition (EB-PVD) thermal barrier coated (partially stabilized zirconia) Rene N5 single crystal superalloy. Damage initiation and failure events due to thermal cycling were investigated. Early crack initiation was rationalized through interfacial asperity induced high stresses between the TBC and the PtAl bond coat . Analytical solution was forwarded for transient and steady-state residual stresses in the EB-PVD system. Oxide scale development as a function of time was predicted using Fick' S Law. The deviation of experimental results from Fick's Law was attributed to microcrack interaction and coalescence. Oxide scale induced internal pressure on crack surfaces was shown to be a plausible mechanism for microcrack growth. Buckling analysis was used to estimate the critical size of delamination necessary (sixteen times the TBC thickness) for spallation. It was shown that for various thermal cycles, spallation life can be estimated based on critical oxide layer thickness. Thermal wave imaging technique was used to track damage condition as a function of thermal cycles. It was found that saturation of thermal wave amplitude corresponds to spallation life of the sample. This work provides a mechanism-based framework for life prediction in TBC systems.
Book Synopsis Metal Failures by : Arthur J. McEvily
Download or read book Metal Failures written by Arthur J. McEvily and published by John Wiley & Sons. This book was released on 2013-09-16 with total page 498 pages. Available in PDF, EPUB and Kindle. Book excerpt: One of the only texts available to cover not only how failure occurs but also examine methods developed to expose the reasons for failure, Metal Failures has long been considered the most definitive and authoritative resources in metallurgical failure analysis. Now in a completely revised edition, this Second Edition features updates of all chapters plus new coverage of elastic behavior and plastic deformation, localized necking, the phenomenological aspects of fatigue, fatigue crack propagation, alloys and coatings, tensors and tensor notations, and much more.
Book Synopsis Mechanisms Controlling the Durability of Thermal Barrier Coatings by :
Download or read book Mechanisms Controlling the Durability of Thermal Barrier Coatings written by and published by . This book was released on 2001 with total page 64 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis High Temperature Coatings by : Sudhangshu Bose
Download or read book High Temperature Coatings written by Sudhangshu Bose and published by Elsevier. This book was released on 2011-04-01 with total page 314 pages. Available in PDF, EPUB and Kindle. Book excerpt: High Temperature Coatings demonstrates how to counteract the thermal effects of the rapid corrosion and degradation of exposed materials and equipment that can occur under high operating temperatures. This is the first true practical guide on the use of thermally-protective coatings for high-temperature applications, including the latest developments in materials used for protective coatings. It covers the make-up and behavior of such materials under thermal stress and the methods used for applying them to specific types of substrates, as well as invaluable advice on inspection and repair of existing thermal coatings.With his long experience in the aerospace gas turbine industry, the author has compiled the very latest in coating materials and coating technologies, as well as hard-to-find guidance on maintaining and repairing thermal coatings, including appropriate inspection protocols. The book will be supplemented with the latest reference information and additional support for finding more application-type and industry-type coatings specifications and uses, with help for the reader in finding more detailed information on a specific type of coating or a specific type of use. · Offers overview of the underlying fundamental concepts of thermally-protective coatings, including thermodynamics, energy kinetics, crystallography, and equilibrium phases· Covers essential chemistry and physics of underlying substrates, including steels, nickel-iron alloys, nickel-cobalt alloys, and titanium alloys· Provides detailed guidance on wide variety of coating types, including those used against high temperature corrosion and oxidative degradation, as well as thermal barrier coatings
