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.
Download or read book Thermo mechanical and Isothermal Fatigue of a Coated Columnar Grained Directionally Solidified Nickel Base Superalloy written by H. Mughrabi and published by . This book was released on 2000 with total page 15 pages. Available in PDF, EPUB and Kindle. Book excerpt: The isothermal low-cycle fatigue (LCF) and the out-of-phase thermomechanical fatigue (TMF) behaviours of the directionally solidified nickel-base superalloy DS CM 247 LC, coated with a plasma-sprayed NiCrAlY-coating (PCA-1), were studied in detail. The investigations were performed on the uncoated, the coated substrate material and also on the pure coating material, in contrast to most existing work. The results of the isothermal LCF tests show that the fatigue life of the substrate/coating-composite is governed by the fatigue behaviour of the bulk coating material. The out-of-phase TMF cyclic deformation behaviour of the substrate/coating-composite reflects that of the components and is well described by an isostrain composite model. When the mechanical strain amplitudes experienced by the coating material are plotted against the fatigue life, the data on the coated material in isothermal LCF tests at the upper and lower temperatures of the TMF cycle, respectively, and in the TMF tests coincide. This gives further evidence that the behaviour of the coating materials governs that of the coated composite.
Download or read book Thermo mechanical Fatigue Behavior of Materials written by Huseyin Sehitoglu and published by ASTM International. This book was released on 2000 with total page 339 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Fatigue Behavior of a Nickel Based Directionally Solidified Superalloy at Elevated Temperature written by Louis Domenic Terranova and published by . This book was released on 1989 with total page 232 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Rene 80 written by Amit Prakash and published by . This book was released on 1981 with total page 330 pages. Available in PDF, EPUB and Kindle. Book excerpt:
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.
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:
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.
Download or read book Low Cycle Fatigue and Elasto Plastic Behaviour of Materials written by P.D. Portella and published by Elsevier. This book was released on 1998-09-30 with total page 890 pages. Available in PDF, EPUB and Kindle. Book excerpt: The 4th International Conference on Low Cycle Fatigue and Elasto-Plastic Behaviour of Materials was held from 7-11 September 1998 in Garmisch-Partenkirchen, Germany. In response to a call for papers, nearly 200 extended abstracts from 32 countries were submitted to the organizing committee. These papers were presented at the conference as invited lectures or short contributions and as oral or poster presentation. All the papers were presented in poster form in extended poster sessions–a peculiarity of the LCF Conferences which allows an intense, thorough discussion of all contributions. Each chapter provides a comprehensive overview of a materials class or a given subject. Many contributions could have been included in two or even three chapters and so, in order to give a better overview of the content, the reader will find a subject index, a material index and an author index in the back of the book.
Download or read book Thermomechanical Fatigue Behavior of a Superalloy written by JL. Malpertu and published by . This book was released on 1988 with total page 13 pages. Available in PDF, EPUB and Kindle. Book excerpt: A thermal-mechanical fatigue test facility is described to study the stress-strain behavior and fatigue damage under anisothermal conditions of materials for gas turbine blading applications. Hollow specimens are heated by a radiation furnace; a microcomputer is used to generate simultaneous strain and temperature signals and tests are conducted under closed-loop control of axial strain. A typical mechanical strain-temperature loop has been used from 600 to 1050°C (873 to 1323 K) with peak strains at intermediate temperatures. Application to IN 100, a nickel base superalloy, is reported. Crack initiation and early crack growth are shown which are deduced from a plastic replication technique. The role of oxidation has been emphasized and the life of thermal mechanical fatigue specimens was found to be in good agreement with low-cycle fatigue results at 1000°C (1273 K).
Download or read book Thermo mechanical Fatigue of Polycrystalline Directionally Solidified and Single Crystal Nickel Base Superalloys Repaired by Laser Beam Welding written by Jonathan Durocher and published by . This book was released on 2013 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
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.
Download or read book Thermomechanical Fatigue Behavior of an Aluminide Coated Monocrystalline Ni Base Superalloy written by H. Mughrabi and published by . This book was released on 2003 with total page 16 pages. Available in PDF, EPUB and Kindle. Book excerpt: This study is part of a project concerned with the effect of diffusional aluminide coatings on the stress response and life of a coated monocrystalline nickel-base superalloy (CMSX-6) during thermomechanical fatigue (TMF) testing.
Download or read book High Temperature Monotonic and Cyclic Deformation in a Directionally Solidified Nickel Base Superalloy written by Eric S. Huron and published by . This book was released on 1986 with total page 332 pages. Available in PDF, EPUB and Kindle. Book excerpt: Directionally solidified (Ds) MAR-M246+Hf was tested in tension and fatigue, at temperatures from 20 C - 1093 C. Tests were performed on (001) oriented specimens at strain rates of 50 % and 0.5 % per minutes. In tension, the yield strength was constant up to 704 C, above which the strength dropped off rapidly. A strong dependence of strength on strain rate was seen at the higher temperatures. The deformation mode was observed to change from heterogeneous to homogeneous with increasing temperature. Low Cycle Fatigue tests were done using a fully reversed waveform and total strain control. for a given plastic strain range, lives increased with increasing temperature. For a given temperature strain rate had a strong effect on life. At 704 C, decreasing strain rates decreased life, while at the higher temperatures, decreasing strain rates increased life, for a given plastic strain range. These results could be explained through considerations of the deformation modes and stress levels. At the higher temperatures, marked coarsening caused beneficial stress reductions, but oxidation limited the life. The longitudinal grain boundaries were found to influence slip behavior. The degree of secondary slip adjacent to the boundaries was found to be related to the degree of misorientation between the grains.
Download or read book Thermomechanical Fatigue Behavior of Materials written by and published by . This book was released on 2003 with total page 344 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book The International Conference on Applied Research and Engineering written by Velaphi Msomi and published by Trans Tech Publications Ltd. This book was released on 2024-03-19 with total page 93 pages. Available in PDF, EPUB and Kindle. Book excerpt: Selected peer-reviewed full text papers from the 3rd International Conference on Applied Research and Engineering (ICARAE2023) Selected peer-reviewed full text papers from the 3rd International Conference on Applied Research and Engineering (ICARAE2023), November 17-19, 2023, Cape Town, South Africa
Download or read book Effect of Grain Orientation and Coating on Thermal Fatigue Resistance of a Directionally Solidified Superalloy MAR M 247 written by and published by . This book was released on 1979 with total page 28 pages. Available in PDF, EPUB and Kindle. Book excerpt:
