Effect Of Dwell Times On Crack Propagation In Superalloys
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Effect Of Dwell Times On Crack Propagation In Superalloys
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Author : Jonas Saarimäki
language : en
Publisher: Linköping University Electronic Press
Release Date : 2015-12-10
Effect Of Dwell Times On Crack Propagation In Superalloys written by Jonas Saarimäki and has been published by Linköping University Electronic Press this book supported file pdf, txt, epub, kindle and other format this book has been release on 2015-12-10 with categories.
Gas turbines are widely used in industry for power generation and as a power source at "hard to reach" locations where other possibilities for electrical supply are insufficient. There is a strong need for greener energy, considering the effect that pollution has had on global warming, and we need to come up with ways of producing cleaner electricity. A way to achieve this is by increasing the combustion temperature in gas turbines. This increases the demand on the high temperature performance of the materials used e.g. superalloys in the turbine. These high combustion temperatures can lead to detrimental degradation of critical components. These components are commonly subjected to cyclic loading of different types e.g. combined with dwell-times and overloads at elevated temperatures, which influence the crack growth. Dwell-times have shown to accelerate crack growth and change the cracking behaviour in both Inconel 718 and Haynes 282. Overloads at the beginning of the dwell-time cycle have shown to retard the dwell time effect on crack growth in Inconel 718. To understand these effects more microstructural investigations are needed. The work presented in this licentiate thesis was conducted under the umbrella of the research program Turbo Power; "High temperature fatigue crack propagation in nickel-based superalloys", concentrating on fatigue crack growth mechanisms in superalloys during dwell-times, which have shown to have a devastating effect on the crack propagation behaviour. Mechanical testing was performed under operation-like conditions in order to achieve representative microstructures and material data for the subsequent microstructural work. The microstructures were microscopically investigated in a scanning electron microscope (SEM) using electron channeling contrast imaging (ECCI) as well as using light optical microscopy. The outcome of this work has shown that there is a significant increase in crack growth rate when dwell-times are introduced at the maximum load (0% overload) in the fatigue cycle. With the introduction of a dwell-time there is also a shift from transgranular to intergranular crack growth for both Inconel 718 and Haynes 282. When an overload is applied prior to the dwell-time, the crack growth rate decreases with increasing overload levels in Inconel 718. At high temperature crack growth in Inconel 718 took place as intergranular crack growth along grain boundaries due to oxidation and the creation of nanometric voids. Another observed growth mechanism was crack advance along phase boundaries with subsequent severe oxidation of the phase. This thesis comprises two parts. The first giving an introduction to the field of superalloys and the acting microstructural mechanisms that influence fatigue during dwell times. The second part consists of two appended papers, which report the work completed so far in the project.
Cracks In Superalloys
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Author : Jonas Saarimäki
language : en
Publisher: Linköping University Electronic Press
Release Date : 2018-01-18
Cracks In Superalloys written by Jonas Saarimäki and has been published by Linköping University Electronic Press this book supported file pdf, txt, epub, kindle and other format this book has been release on 2018-01-18 with categories.
Gas turbines are widely used in industry for power generation and as a power source at hard to reach locations where other possibilities for electrical power supplies are insufficient. New ways of producing greener energy is needed to reduce emission levels. This can be achieved by increasing the combustion temperature of gas turbines. High combustion temperatures can be detrimental and degrade critical components. This raises the demands on the high temperature performance of the superalloys used in gas turbine components. These components are frequently subjected to different cyclic loads combined with for example dwell-times and overloads at elevated temperatures, which can influence the crack growth. Dwell-times have been shown to accelerate crack growth and change cracking behaviour in both Inconel 718, Haynes 282 and Hastelloy X. On the other hand, overloads at the beginning of a dwell-time cycle have been shown to retard the dwell-time effect on crack growth in Inconel 718. More experiments and microstructural investigations are needed to better understand these effects. The work presented in this thesis was conducted under the umbrella of the research program Turbo Power; "High temperature fatigue crack propagation in nickel-based superalloys", where I have mainly looked at fatigue crack growth mechanisms in superalloys subjected to dwell-fatigue, which can have a devastating effect on crack propagation behaviour. Mechanical testing was performed under operation-like cycles in order to achieve representative microstructures and material data for the subsequent microstructural work. Microstructures were investigated using light optical microscopy and scanning electron microscopy (SEM) techniques such as electron channeling contrast imaging (ECCI) and electron backscatter diffraction (EBSD). The outcome of this work has shown that there is a significant increase in crack growth rate when dwell-times are introduced at maximum load (0 % overload) in the fatigue cycle. With the introduction of a dwell-time there is also a shift from transgranular to intergranular crack growth for both Inconel 718 and Haynes 282. The crack growth rate decreases with increasing overload levels in Inconel 718 when an overload is applied prior to the dwell-time. At high temperature, intergranular crack growth was observed in Inconel 718 as a result of oxidation and the creation of nanometric voids. Another observed growth mechanism was crack advance along ?-phase boundaries with subsequent oxidation of the ?-phase. This thesis comprises two parts. Part I gives an introduction to the field of superalloys and the acting microstructural mechanisms related to fatigue and crack propagation. Part II consists of five appended papers, which report the work completed as part of the project.
Dwell Time Fatigue Crack Growth In Ni Base Superalloys
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Author :
language : en
Publisher:
Release Date : 2003
Dwell Time Fatigue Crack Growth In Ni Base Superalloys written by and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 2003 with categories.
The state-of-the-art dwell-time fatigue crack growth models applicable to materials systems such as Waspaloy, Rene'95, Rene'88 and IN 100 were critically assessed. The review included models based on linear elastic fracture mechanics (LEFM) and those based on time dependent fracture mechanics (TDFM). The pertinent creep deformation and time and cycle dependent crack growth rate data on these materials were also collected to enable the evaluation of these models and for the establishment of their respective regimes of applicability and their limitations. The gaps in the available experimental and computational data for implementing the promising models were identified as part of the review. An experimental test plan and a plan for providing computational needs for addressing these shortcomings are proposed.
Superalloys 2012
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Author : Eric S. Huron
language : en
Publisher: John Wiley & Sons
Release Date : 2012-10-02
Superalloys 2012 written by Eric S. Huron and has been published by John Wiley & Sons this book supported file pdf, txt, epub, kindle and other format this book has been release on 2012-10-02 with Technology & Engineering categories.
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.
Superalloys 2020
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Author : Sammy Tin
language : en
Publisher: Springer Nature
Release Date : 2020-08-28
Superalloys 2020 written by Sammy Tin and has been published by Springer Nature this book supported file pdf, txt, epub, kindle and other format this book has been release on 2020-08-28 with Technology & Engineering categories.
The 14th International Symposium on Superalloys (Superalloys 2020) highlights technologies for lifecycle improvement of superalloys. In addition to the traditional focus areas of alloy development, processing, mechanical behavior, coatings, and environmental effects, this volume includes contributions from academia, supply chain, and product-user members of the superalloy community that highlight technologies that contribute to improving manufacturability, affordability, life prediction, and performance of superalloys.
Fatigue
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Author : John J. Burke
language : en
Publisher: Springer Science & Business Media
Release Date : 2013-11-11
Fatigue written by John J. Burke and has been published by Springer Science & Business Media this book supported file pdf, txt, epub, kindle and other format this book has been release on 2013-11-11 with Technology & Engineering categories.
The Army Materials and Mechanics Research Center in coop eration with the Materials Science Group of the Department of Chemical Engineering and Materials Science of Syracuse University has been conducting the Annual Sagamore Army Materials Research Conference since 1954. The specific purpose of these conferences has been to bring together scientists and engineers from academic institutions, industry and government who are uniquely qualified to explore in depth a subject of importance to the Department of Defense, the Army and the scientific community. These proceedings entitled, FATIGUE - ENVIRONMENT AND TEMPER ATURE EFFECT, address the overview of temperature and environmental effects of fatigue, room temperature environmental effects, high temperature and environmental effect - mechanisms, high tempera ture and environmental effect - mechanisms, materials and design-engineering applications. We wish to acknowledge the assistance of Messrs. Joseph Bernier and Dan McNaught of the Army Materials and Mechanics Research Center and Helen Brown DeMascio of Syracuse University throughout the stages of the conference planning and finally the publication of the book. The continued active interest and support of these conferences by Dr. E. Wright, Director of the Army Materials and Mechanics Research Center, is appreciated.
Fatigue Durability And Fracture Mechanics
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Author : S. Seetharamu
language : en
Publisher: Springer Nature
Release Date : 2020-10-01
Fatigue Durability And Fracture Mechanics written by S. Seetharamu and has been published by Springer Nature this book supported file pdf, txt, epub, kindle and other format this book has been release on 2020-10-01 with Science categories.
This book presents selected papers presented during Fatigue Durability India 2019. The contents of this volume discuss advances in the field of fatigue, durability, and fracture, and cover mechanical failure and its applications. The chapters cover a wide spectrum of topics, including design, engineering, testing and computational evaluation of the components or systems for fatigue, durability, and fracture mechanics. The contents of this book will appeal not only to academic researchers, but also to design engineers, failure analysts, maintenance engineers, certification personnel, and R&D professionals involved in a wide variety of industries.
Fatigue Crack Propagation In Metals And Alloys
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Author : Ulrich Krupp
language : en
Publisher: John Wiley & Sons
Release Date : 2007-06-27
Fatigue Crack Propagation In Metals And Alloys written by Ulrich Krupp and has been published by John Wiley & Sons this book supported file pdf, txt, epub, kindle and other format this book has been release on 2007-06-27 with Technology & Engineering categories.
This comprehensive overview of the whole field of fatigue and fracture of metallic materials covers both the theoretical background and some of the latest experimental techniques. It provides a summary of the complex interactions between material microstructure and cracks, classifying them with respect to the overall damage process with a focus on microstructurally short cracks and dynamic embrittlement. It furthermore introduces new concepts for the numerical treatment of fatigue microcrack propagation and their implementation in fatigue-life prediction models.This comprehensive overview of the whole field of fatigue and fracture of metallic materials covers both the theoretical background and the latest experimental techniques. It provides a summary of the complex interactions between material microstructure and cracks, classifying them with respect to the overall damage process. It furthermore introduces new concepts for the numerical treatment of fatigue microcrack propagation and their implementation in fatigue-life prediction models.
Mechanical Behaviour Of Materials At High Temperature
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Author : C. Moura Branco
language : en
Publisher: Springer Science & Business Media
Release Date : 1996-06-30
Mechanical Behaviour Of Materials At High Temperature written by C. Moura Branco and has been published by Springer Science & Business Media this book supported file pdf, txt, epub, kindle and other format this book has been release on 1996-06-30 with Science categories.
This volume contains the edited version of lectures and selected research contributions presented at the NATO ADVANCED STUDY INSTITUTE on MECHANICAL BEHA VI OUR OF MATERIALS AT HIGH TEMPERATURE, held in Sesimbra, Portugal, 12th-22nd September 1995, and organized by 1ST-Lisbon Institute of Technology, PortugaL The Institute was attended by 88 participants, including 15 lecturers from 17 countries including five CP countries. The lecturers were leading scientists and technologists from universities, research institutions and industry. The students were mainly young PhD students and junior academic or research staff with postgraduate qualifications (MSc or PhD). Fourteen students were from the five CP countries. The students presented research papers or posters during the Institute reporting the current progress of their research projects. A total of thirty three lectures, ten research papers and fifty posters were presented. This book does not contain the poster presentations and seven research papers were selected for publication. All the sessions were very active and quite extensive discussions on scientific aspects took place during the Institute. The Advanced Study Institute provided a forum for interaction among scientists and engineers from different areas of research, and young researchers.
Coutsouradis Mater Ials For Adv Prt 2
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Author : D. Coutsouradis
language : en
Publisher: Springer Science & Business Media
Release Date : 1994-08-15
Coutsouradis Mater Ials For Adv Prt 2 written by D. Coutsouradis and has been published by Springer Science & Business Media this book supported file pdf, txt, epub, kindle and other format this book has been release on 1994-08-15 with Science categories.
The role of energy in the modern world goes beyond mere technology and economics to influence welfare, the environment, the quality of life and, in broad terms, civilization itself. Since the industrial revolution, energy conservation technology has been at the forefront of the innovation required to satisfy the needs of mankind and, more than any other, this technology has always depended on the performance of the materials used. In this, the report of the Fifth Li??ge Conference devoted to a review of the work of the European Materials Collaborative Programmes, the results of the programmes are presented along the following technology oriented themes: steam power plant gas turbines diesel engines advanced combustion perspectives. The book thus presents one of the most up to date references available anywhere on materials technologies in energy conversion from fossil fuels and materials for high efficiency, low emission systems.