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Thermo Mechanical Fatigue Investigations On Nickel Base Superalloys And Creep Of Nial Thin Films
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Book Synopsis Thermo-mechanical Fatigue Investigation of Single Crystal Nickel Base Superalloy SRR99 by : F. Rézaï-Aria
Download or read book Thermo-mechanical Fatigue Investigation of Single Crystal Nickel Base Superalloy SRR99 written by F. Rézaï-Aria and published by . This book was released on 2000 with total page 15 pages. Available in PDF, EPUB and Kindle. Book excerpt: This paper deals with the comparison between thermal fatigue (TF) and thermomechanical fatigue (TMF) testing for SRR99 superalloy. First, a measured TF mechanical strain-temperature (?m-T) profile between 200°C and 1100°C has been reproduced on a TMF specimen to allow for an estimation of the stresses and inelastic strains which occur during TF. Thermal-fatigue-based (TFB) ?m-T profiles were determined based on the measured TF profiles. These TFB cycles, together with the well-known out-of-phase profile, were employed for all of TMF tests. The comparison of the results reveals that the TF and TMF out-phase tests are more damaging in terms both of the applied stress and strain range, while the TMF out-of-phase test is more severe if the comparison is made in terms of the inelastic strain range. Finally, it is shown that the results can be rationalized quite well by plotting the fatigue lives as a function of the maximum stabilized stress (?max).
Book Synopsis Enhancement of Thermomechanical Fatigue Resistance of a Monocrystalline Nickel-base Superalloy by Pre-rafting by : U. Tetzlaff
Download or read book Enhancement of Thermomechanical Fatigue Resistance of a Monocrystalline Nickel-base Superalloy by Pre-rafting written by U. Tetzlaff and published by . This book was released on 2003 with total page 15 pages. Available in PDF, EPUB and Kindle. Book excerpt: In ?'-hardened monocrystalline nickel-base superalloys having a negative ?/?' lattice misfit, the prior introduction of so-called ?/?' rafts aligned parallel to the stress axis (by a small creep pre-deformation in compression) has been shown to enhance both the high-temperature isothermal fatigue strength and the tensile creep resistance. It was hence of interest to perform a systematic study of the thermo-mechanical fatigue (TMF) behavior of specimens of a monocrystalline nickel-base superalloy with the main aim to test whether an initial ?/?' raft microstructure can also enhance the TMF resistance. The experiments were performed on [001]-orientated monocrystalline specimens of the superalloy SRR 99 which contained either the initial ?/?'-microstructure with cuboidal ?' precipitates or a ?/?' raft microstructure aligned roughly parallel to the stress axis. The latter was introduced by a small compressive creep deformation of less than 0.4% at a temperature of 1050°C and a stress of 120 MPa. Different strain-controlled TMF cycle forms were employed. However, in most tests a counter-clockwise-diamond (CCD) cycle (temperature interval ?T = 600°C-1100°C) was used with a total strain rate of 6.67•10-5 s-1. This CCD cycle is considered to be close to service conditions. The mechanical strain range ??m was varied in the range of ??mech = 1%, leading to fatigue lives in the order of some 1000 cycles. It could be shown that pre-rafting in compression enhances the TMF fatigue life significantly for all cases of CCD-cycles investigated.
Book Synopsis Thermomechanical Fatigue Behavior of the Directionally-solidified Nickel-base Superalloy CM247LC by : Robert Anthony Kupkovits
Download or read book Thermomechanical Fatigue Behavior of the Directionally-solidified Nickel-base Superalloy CM247LC written by Robert Anthony Kupkovits and published by . This book was released on 2009 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Due to the extreme operating conditions present in the combustion sections of gas turbines, designers have relied heavily on specialized engineering materials. For blades, which must retain substantial strength and resistance to fatigue, creep, and corrosion at high temperatures, directionally-solidified (DS) nickel-base superalloys have been used extensively. Complex thermomechanical loading histories makes life prediction for such components difficult and subjective. Costly product inspection and refurbishment, as well as capital expense required in turbine forced outage situations, are significant drains on the resources of turbine producers. This places a premium on accurate endurance prediction as the foundation of viable long-term service contracts with customers. In working towards that end, this work characterizes the behavior of the blade material CM247LC DS subjected to a variety of in-phase (IP) and out-of phase (OP) loading cycles in the presence of notch stress concentrations. The material response to multiaxial notch effects, highly anisotropic material behavior, time-dependent deformation, and waveform and temperature cycle characteristics is presented. The active damage mechanisms influencing crack initiation are identified through extensive microscopy as a function of these parameters. This study consisted of an experimental phase as well as a numerical modeling phase. The first involved conducting high temperature thermomechanical fatigue (TMF) tests on both smooth and notched round-bar specimens to compile experimental results. Tests were conducted on longitudinal and transverse material grain orientations. Damage is characterized and conclusions drawn in light of fractography and microscopy. The influences of microstructure morphology and environmental effects on crack initiation are discussed. The modeling phase utilized various finite element (FE) simulations. These included an anisotropic-elastic model to capture the purely elastic notch response, and a continuum-based crystal visco-plastic model developed specifically to compute the material response of a DS Ni-base superalloy based on microstructure and orientation dependencies. These FE simulations were performed to predict and validate experimental results, as well as identify the manifestation of damage mechanisms resulting from thermomechanical fatigue. Finally, life predictions using simple and complex analytical modeling methods are discussed for predicting component life at various stages of the design process.
Book Synopsis Scientific and Technical Aerospace Reports by :
Download or read book Scientific and Technical Aerospace Reports written by and published by . This book was released on 1994 with total page 312 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Thermomechanical Fatigue Crack Formation in Nickel-base Superalloys at Notches by : Patxi Fernandez-Zelaia
Download or read book Thermomechanical Fatigue Crack Formation in Nickel-base Superalloys at Notches written by Patxi Fernandez-Zelaia and published by . This book was released on 2012 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Hot sections of gas engine turbines require specialized materials to withstand extreme conditions present during engine operation. Nickel-base superalloys are typically used as blades and disks in the high pressure turbine section because they possess excellent fatigue strength, creep strength and corrosion resistance at elevated temperatures. Components undergo thermomechanical fatigue conditions as a result of transient engine operation. Sharp geometric features, such as cooling holes in blades or fir-tree connections in disks, act as local stress raisers. The material surrounding these features are potential sites of localized inelastic deformation and crack formation. To reduce customer costs associated with unnecessary overhauls or engine down-time, gas turbine manufacturers require accurate prediction methods to determine component endurances. The influence of stress concentration severity on thermomechanical fatigue crack formation is of particular importance as cracks often initiate in these hot spots. Circumferentially notched specimens were utilized to perform thermomechanical fatigue experiments on blade material CM247LC DS and disk material PM IN100. A parametric study on CM247LC DS was performed utilizing four notched specimens. Experimental results were coupled with finite element simulations utilizing continuum based constitutive models. The effects of applied boundary conditions on crack initiation life was studied in both alloys by performing experiments under remotely applied force and displacement boundary conditions. Finite element results were utilized to develop a life prediction method for notched components under thermomechanical fatigue conditions.
Book Synopsis International Aerospace Abstracts by :
Download or read book International Aerospace Abstracts written by and published by . This book was released on 1999 with total page 974 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Experimental and Computational Investigation of Multi-axial Thermal Gradient Mechanical Fatigue in a Nickel-based Superalloy by : Jingyu Sun
Download or read book Experimental and Computational Investigation of Multi-axial Thermal Gradient Mechanical Fatigue in a Nickel-based Superalloy written by Jingyu Sun and published by . This book was released on 2018 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Thermo-Mechanical Fatigue of the Monocrystalline Nickel-Base Superalloy CMSX-6 by : SA. Kraft
Download or read book Thermo-Mechanical Fatigue of the Monocrystalline Nickel-Base Superalloy CMSX-6 written by SA. Kraft and published by . This book was released on 1996 with total page 14 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Elevated Temperature Fatigue-creep Behavior of Nickel-base Superalloy in 625 by :
Download or read book Elevated Temperature Fatigue-creep Behavior of Nickel-base Superalloy in 625 written by and published by . This book was released on 1986 with total page 40 pages. Available in PDF, EPUB and Kindle. Book excerpt: Superalloy Inconel 625 is a potential candidate material for use in structural components subjected to cyclic loadings at high temperatures, such as parts of jet engines and nuclear reactors. This report discusses the results of a research program carried out to provide the mechanical properties on the low-cycle fatigue and creep-fatigue behaviour of IN 625 at elevated temperatures (650 and 815C). Under continuous cycling, the data base of the material is established and the influence of hold-times introduced in each cycle (interspersed creep-fatigue) on the material life is then examined. A life prediction procedure recently suggested was applied to the data obtained under cyclic loading, with and without hold times. The overall correlation between isothermal experimental results and theoretical predictions is discussed.
Download or read book Energy Research Abstracts written by and published by . This book was released on 1990 with total page 852 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Thermal-mechanical Fatigue Behavior of Nickel-base Superalloys by : Norman J. Marchand
Download or read book Thermal-mechanical Fatigue Behavior of Nickel-base Superalloys written by Norman J. Marchand and published by . This book was released on 19?? with total page 884 pages. Available in PDF, EPUB and Kindle. Book excerpt: This report presents the main achievements of a 36-month research program the main objective of which was to gain more insight into the problem of crack growth under thermal mechanical fatigue (TMF) conditions. The program was arranged into five technical tasks. Under Task I, the goal was to identify the crack propagation conditions in aircraft engines (hot section) and to assess the validity of conventional fracture mechanics parameters to address TMF crack growth. The second task defined the test facilities, test specimen and the testing conditions needed to establish the effectiveness of data correlation parameters identified in Task I. Under Task III, a computerized testing system to measure the TMF behavior (LCF and CG behaviors) of various alloy systems was built. A crack propagation test program was defined and conducted under Task IV. The test variables included strain range, strain rate (frequency) and temperature. Task V correlated and generalized the Task IV data for isothermal and variable temperature conditions so that several crack propagation parameters could be compared and evaluated.
Book Synopsis Thermal-mechanical Fatigue Behavior of Nickel-base Superalloys by : R. M. Pelloux
Download or read book Thermal-mechanical Fatigue Behavior of Nickel-base Superalloys written by R. M. Pelloux and published by . This book was released on 1986 with total page 14 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Collaborative Research on Thermo-Mechanical and Isothermal Low-Cycle Fatigue Strength of Ni-Base Superalloys and Protective Coatings at Elevated Temperatures in The Society of Materials Science, Japan (JSMS) by : Y. Yamazaki
Download or read book Collaborative Research on Thermo-Mechanical and Isothermal Low-Cycle Fatigue Strength of Ni-Base Superalloys and Protective Coatings at Elevated Temperatures in The Society of Materials Science, Japan (JSMS) written by Y. Yamazaki and published by . This book was released on 2003 with total page 15 pages. Available in PDF, EPUB and Kindle. Book excerpt: Results of collaborative research by "Subcommittee on Superalloys and Coatings" in The Society of Materials Science, Japan (JSMS), are presented, which cover the thermo-mechanical fatigue (TMF) and high temperature isothermal low-cycle fatigue (ILCF) strengths of Ni-Base superalloy, substrate alloys and the protective coatings. Three kinds of Ni-base superalloys were selected as the substrate: a single crystal alloy, CMSX-4; a directionally solidified alloy, CM247LC; and a polycrystalline alloy, IN738LC. On these substrate specimens the CoNiCrAlY alloy was coated by 250 ?m in thickness by low pressure plasma spraying, and then aluminized. This process was managed and undertaken by one of member companies of the Subcommittee. The round robin TMF and ILCF tests were carried out under a strain ratio of -1 at temperature ranged between 400 and 900°C. In the former the tests were performed under the out-of-phase and diamond phase conditions in which the phase difference between strain and temperature were 180° and 90°, respectively. It is shown by the round-robin tests that the TMF lives, as well as the ILCF, were strongly dependent on the substrate alloys. Many important, or noteworthy results were also found: e.g., the TMF fracture behavior of the coated specimens revealed some unique characteristics that were hardly deduced from that of the bare specimens. The effect of coating on the ILCF life was strongly dependent on the temperature. It was not reasonable, or difficult to try to estimate the TMF life of the coatings from the ILCF test results. Based on the observations on the crack initiation, propagation and the fracture surface, the effects of the substrate alloy and the coating on the TMF and ILCF lives were discussed.
Book Synopsis Thermomechanical and Low Cycle Fatigue Properties and Their Relation to Creep for the Nickel Base Alloys IN738LC and IN597 by : G. Engberg
Download or read book Thermomechanical and Low Cycle Fatigue Properties and Their Relation to Creep for the Nickel Base Alloys IN738LC and IN597 written by G. Engberg and published by . This book was released on 1984 with total page 30 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Thermomechanical Response of Single Crystal Nickel-base Superalloy CM186 SX by : DJ. Smith
Download or read book Thermomechanical Response of Single Crystal Nickel-base Superalloy CM186 SX written by DJ. Smith and published by . This book was released on 2003 with total page 17 pages. Available in PDF, EPUB and Kindle. Book excerpt: CM186 SX is a second generation Rhenium (Re) containing single crystal nickel-base superalloy, which exhibits improved creep and oxidation performance compared with its first generation counterparts. In this paper, the thermomechanical (TMF) response of coated and uncoated 001 single crystal nickel-base superalloy, CM186 SX is presented. In-phase (IP) and Out-of-Phase (OP) cycles were examined using coated and uncoated hollow dumbbell test pieces. Linear heating and cooling with a temperature rate of 6°C/s between 350 and 950°C was applied. The tests were mechanical strain controlled with strain ranges between 0.5 to 1.0%. Detailed examination of the experimental results revealed that variations in wall thickness of the hollow test pieces played a significant role in the set-up of the experiments and interpretation of the results. Finite element analysis was also performed to investigate the influence of the variation in wall thickness and its relevance to the experimental results. Overall, the results showed that the coating reduced the TMF life, particularly for OP cycles. Brittle cracking of the coating, especially at low temperatures, occurred at low strains. For the IP cycle the coating appeared to have less of an influence on life than for OP cycles. The results are compared with those from an earlier program using solid rectangular test pieces.
Book Synopsis Thermomechanical and Bithermal Fatigue Behavior of Cast B1900 + Hf and Wrought Haynes 188 by : National Aeronautics and Space Adm Nasa
Download or read book Thermomechanical and Bithermal Fatigue Behavior of Cast B1900 + Hf and Wrought Haynes 188 written by National Aeronautics and Space Adm Nasa and published by . This book was released on 2018-10-18 with total page 28 pages. Available in PDF, EPUB and Kindle. Book excerpt: High temperature thermomechanical and bithermal fatigue behavior was investigated for two superalloys: cast nickel-base B1900+Hf and wrought cobalt-base Haynes 188. Experimental results were generated to support development of an advanced thermal fatigue life prediction method. Strain controlled thermomechanical and load-controlled, strain-limited, bithermal fatigue tests were used to determine the fatigue crack initiation and cyclic stress-strain response characteristics of superalloys. Bithermal temperatures of 483 and 871 C were used for B1900+Hf, and 316 and 760 C for Haynes 188. Thermomechanical fatigue tests were conducted by using maximum and minimum temperatures corresponding to those for the bithermal experiments. Lives cover the range from about 10 to 3000 cycles to failure. Isothermal fatigue results obtained previously are also discussed. Halford, Gary R. and Verrilli, Michael J. and Kalluri, Sreeramesh and Ritzert, Frank J. and Duckert, Rob E. and Holland, Frederic A. Glenn Research Center RTOP 553-13-00...
Book Synopsis Low Cycle Fatigue and Thermo-mechanical Fatigue of Uncoated and Coated Nickel-base Superalloys by : Svjetlana Šteković
Download or read book Low Cycle Fatigue and Thermo-mechanical Fatigue of Uncoated and Coated Nickel-base Superalloys written by Svjetlana Šteković and published by . This book was released on 2007 with total page 179 pages. Available in PDF, EPUB and Kindle. Book excerpt:
