Download or read book Characterization of Microstructure Evolution of Nickel Base Superalloys in Support of the Development of a Grain Growth Model written by Daniel Richard Corwin and published by . This book was released on 2007 with total page 224 pages. Available in PDF, EPUB and Kindle. Book excerpt: Abstract: I would like to thank Dr. Michael Mills, my adviser, for providing excellent support and guidance throughout this work. I'd also like to thank Eric Payton for his contributions and advice regarding practically all aspects of this project. Close collaboration with Dr. Yunzhi Wang, Gang Wang, and Ning Ma has been a very beneficial experience that has given me a valuable understanding of microstructure modeling. I am also very appreciative of the help received from Peter Sarosi, Libor Kovarik, and Ray Unocic regarding the transmission electron microscopy performed in this research. I wish to thank Dave Mourer, Deb Whitis, and Dan Wei at GE Aviation for providing guidance and direction in addition to making this research opportunity possible. Thanks to Ron Tolbert for helping procure the needed materials. I am grateful for the superior quality of the Campus Electron Optics Facility at OSU, and I'd like to specifically thank Cameron Begg and Henk Colijn for their assistance with SEM and TEM operation. This research was funded by GE Aviation.

Download or read book Alloy Design and Characterization of Strengthened Nickel based Superalloys for Additive Manufacturing written by Jinghao Xu and published by Linköping University Electronic Press. This book was released on 2021-01-28 with total page 63 pages. Available in PDF, EPUB and Kindle. Book excerpt: Nickel-based superalloys, an alloy system bases on nickel as the matrix element with the addition of up to 10 more alloying elements including chromium, aluminum, cobalt, tungsten, molybdenum, titanium, and so on. Through the development and improvement of nickel-based superalloys in the past century, they are well proved to show excellent performance at the elevated service temperature. Owing to the combination of extraordinary high-temperature mechanical properties, such as monotonic and cyclic deformation resistance, fatigue crack propagation resistance; and high-temperature chemical properties, such as corrosion and oxidation resistance, phase stability, nickel-based superalloys are widely used in the critical hot-section components in aerospace and energy generation industries. The success of nickel-based superalloy systems attributes to both the well-tailored microstructures with the assistance of carefully doped alloying elements, and the intently developed manufacturing processes. The microstructure of the modern nickel-based superalloys consists of a two-phase configuration: the intermetallic precipitates (Ni,Co)3(Al,Ti,Ta) known as γ′ phase dispersed into the austenite γ matrix, which is firstly introduced in the 1940s. The recently developed additive manufacturing (AM) techniques, acting as the disruptive manufacturing process, offers a new avenue for producing the nickel-based superalloy components with complicated geometries. However, γ′ strengthened nickel-based superalloys always suffer from the micro-cracking during the AM process, which is barely eliminated by the process optimization. On this basis, the new compositions of γ′ strengthened nickel-based superalloy adapted to the AM process are of great interest and significance. This study sought to design novel γ′ strengthened nickel-based superalloys readily for AM process with limited cracking susceptibility, based on the understanding of the cracking mechanisms. A two-parameter model is developed to predict the additive manufacturability for any given composition of a nickel-based superalloy. One materials index is derived from the comparison of the deformation-resistant capacity between dendritic and interdendritic regions, while another index is derived from the difference of heat resistant capacity of these two spaces. By plotting the additive manufacturability diagram, the superalloys family can be categorized into the easy-to-weld, fairly-weldable, and non-weldable regime with the good agreement of the existed knowledge. To design a novel superalloy, a Cr-Co-Mo-W-Al-Ti-Ta-Nb-Fe-Ni alloy family is proposed containing 921,600 composition recipes in total. Through the examination of additive manufacturability, undesired phase formation propensity, and the precipitation fraction, one composition of superalloy, MAD542, out of the 921,600 candidates is selected. Validation of additive manufacturability of MAD542 is carried out by laser powder bed fusion (LPBF). By optimizing the LPBF process parameters, the crack-free MAD542 part is achieved. In addition, the MAD542 superalloy shows great resistance to the post-processing treatment-induced cracking. During the post-processing treatment, extensive annealing twins are promoted to achieve the recrystallization microstructure, ensuring the rapid reduction of stored energy. After ageing treatment, up to 60-65% volume fraction of γ′ precipitates are developed, indicating the huge potential of γ′ formation. Examined by the high-temperature slow strain rate tensile and constant loading creep testing, the MAD542 superalloy shows superior strength than the LPBF processed and hot isostatic pressed plus heat-treated IN738LC superalloy. While the low ductility of MAD542 is existed, which is expected to be improved by modifying the post-processing treatment scenarios and by the adjusting building direction in the following stages of the Ph.D. research. MAD542 superalloy so far shows both good additive manufacturability and mechanical potentials. Additionally, the results in this study will contribute to a novel paradigm for alloy design and encourage more γ′-strengthened nickel-based superalloys tailored for AM processes in the future.

Download or read book Nickel Base Single Crystals Across Length Scales written by Loeïz Nazé and published by Elsevier. This book was released on 2021-09-28 with total page 612 pages. Available in PDF, EPUB and Kindle. Book excerpt: Nickel Base Single Crystals Across Length Scales is addresses the most advanced knowledge in metallurgy and computational mechanics and how they are applied to superalloys used as bare materials or with a thermal barrier coating system. Joining both aspects, the book helps readers understand the mechanisms driving properties and their evolution from fundamental to application level. These guidelines are helpful for students and researchers who wish to understand issues and solutions, optimize materials, and model them in a cross-check analysis, from the atomistic to component scale. The book is useful for students and engineers as it explores processing, characterization and design. - Provides an up-to-date overview on the field of superalloys - Covers the relationship between microstructural evolution and mechanical behavior at high temperatures - Discusses both basic and advanced modeling and characterization techniques - Includes case studies that illustrate the application of techniques presented in the book

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.

Download or read book Grain Growth Phenomena in P M Ni base Superalloys written by Kai Song and published by . This book was released on 2005 with total page 272 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Characterization and Modeling of Grain Coarsening in Powder Metallurgical Nickel based Superalloys written by Eric John Payton and published by . This book was released on 2009 with total page 489 pages. Available in PDF, EPUB and Kindle. Book excerpt: Abstract: Accurate prediction of grain size as a function of processing conditions is highly sought after in many advanced alloy systems because specific grain sizes must be obtained to meet mechanical property requirements. In powder metallurgical nickel-based superalloys for turbine disk applications, physics-based modeling of grain coarsening is needed to accelerate alloy and process development and to meet demands for higher jet engine operating temperatures. Materials characterization and simulation techniques were integrated and applied simultaneously to enable quantitative representation of the microstructure, to clarify experimental results, and to validate mean-field descriptions of microstructural evolution. The key parameters controlling grain coarsening behavior were identified. A statistical-analytical mean-field model of grain coarsening with an adaptive spatio-temporal mesh was developed to enable rapid physics-based simulation of microstructural evolution. Experimental results were used as initial conditions and the model was then evaluated in the context of experimental results. Deviations of model predictions from experimental observations were then used to recommend future work to resolve remaining issues related to the microstructural evolution of powder metallurgical nickel-based superalloys, the mean-field modeling of microstructural evolution, and the quantitative characterization of materials.

Download or read book Introduction to Texture Analysis written by Olaf Engler and published by CRC Press. This book was released on 2009-11-16 with total page 490 pages. Available in PDF, EPUB and Kindle. Book excerpt: The first edition of Introduction to Texture Analysis: Macrotexture, Microtexture, and Orientation Mapping broke new ground by collating seventy years worth of research in a convenient single-source format. Reflecting emerging methods and the evolution of the field, the second edition continues to provide comprehensive coverage of the concepts, pra

Download or read book Characterization and Modeling of Microstructure Development in Nickel base Superalloy Welds written by and published by . This book was released on 2001 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Welding is important for economical reuse and reclamation of used and failed nickel-base superalloy blades, respectively[1]. Solidification and solid state decomposition of[gamma] (Face Centered Cubic, FCC) phase into[gamma][prime] (L1[sub 2]-ordered) phase control the properties of these welds. In previous publications, the microstructure development in electron beam welds of PWA-1480 alloy[2] and laser beam welds of CMSX-4 alloy[3] were presented. These results showed that the weld cracking in these alloys were associated with low melting point eutectic at the dendrite boundaries[1,2]. The eutectic-[gamma][prime] precipitation was reduced at rapid weld cooling rates and the partitioning between[gamma]-[gamma][prime] phase was found to be far from equilibrium conditions[3,4]. This observation was related to diffusional growth of[gamma][prime] precipitate into[gamma] phase. Subsequent to the above work, the precipitation characteristics of[gamma][prime] phase from[gamma] phase were evaluated during continuous cooling conditions[5]. The results show that the number density of[gamma] precipitates increased with an increase in cooling rate. However, the details of this decomposition and also the fine-scale elemental partitioning characteristics between[gamma]-[gamma][prime] were not investigated. In this paper, the precipitation characteristics of[gamma][prime] from[gamma] during continuous cooling conditions were investigated with transmission electron microscopy, and atom probe field ion microscopy. In addition, thermodynamic and kinetic models were used to describe microstructure development in Ni-base superalloy welds.

Download or read book Characterisation of the Microstructural Evolution of Single Crystal Nickel base Superalloys written by D. C. Cox and published by . This book was released on 2001 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book On the Path dependent Microstructure Evolution of an Advanced Powder Metallurgy Nickel base Superalloy During Heat Treatment written by Nicholas J. Krutz and published by . This book was released on 2020 with total page 157 pages. Available in PDF, EPUB and Kindle. Book excerpt: The realization of advanced alloy compositions in service relies on a thorough understanding of metallurgical processing variables. Within this work, the gamma prime precipitation of an advanced powder metallurgy nickel-base superalloy during controlled cooling from supersolvus temperatures is compared to prior alloy generations using a complement of characterization and modeling approaches. The on-cooling precipitation of the alloy is studied and characterized to calibrate a multi-scale precipitation model. The proposed framework incorporates a computationally efficient addition to the mean-field modeling approach that increases its ability to model dynamic, multi-modal gamma prime burst events. The gamma prime size predicted by the model shows good agreement with experimental results. The precipitation calculation is applied to the element integration points of a continuum Finite Element heat conduction simulation, where the latent heat generated from the precipitation is accounted for. The results are compared to experimental findings and indicate potential use of the model for evaluating precipitation effects at multiple length scales. The lattice misfit evolution of two commercial PM nickel superalloys during cooling from supersolvus temperatures is also characterized, using in-situ synchrotron X-Ray Diffraction (XRD). The diffraction pattern deconvolution necessary for quantifying misfit was accomplished by combining observation of the superlattice peak intensities with thermodynamic modeling to quantify the intensity relationship between the overlapping phases. The misfit from the XRD measurements was compared to the Scanning Electron Microscopy observations of gamma prime particle shapes for a subset of the experimental conditions. The trend of measured misfit agreed with the microstructural characterization. Time-resolved observations of the on-cooling lattice parameter suggest that lower-temperature changes to the peak intensity characteristics coincide with low misfit magnitudes and a plausible connection to gamma prime burst events. Variation in cooling rate for this alloy and its predecessors shows a tendency for unstable precipitate growth with slower rates. To better understand the effect of precipitate morphology on defect interaction, a series of lab heat treatments of varied cooling rates were carried out and the mechanical response characterized. A phase-field based approach is used to simulate the growth instability of gamma prime precipitates during cooling and compared to post-mortem characterization using serial sectioning and reconstruction. Phase-field modeling is then used to interrogate the interaction of the particle morphology with planar dislocation evolution. It was determined that the incipient stages of particle evolution are dictated by interface growth instability more so than elastic anisotropy effects. Planar deformation in the presence of more evolved particles tended to promote Orowan looping while smaller particles with smaller gamma channel widths showed a tendency for stacking fault formation under the conditions characterized. To further understand precipitate morphology on properties, a stand-alone spectral-based microelasticity model is employed to predict the stress field around the particles. First order deformation assumptions are assessed to understand the effect of the microelastic stress field interacting with dislocations. By comparing the fields of varied precipitate morphologies, it is observed that the magnitudes and spatial distribution of the stress tensor components vary by morphology and may contribute to differences from a defect interaction standpoint.

Download or read book Superalloys 2016 written by Mark C. Hardy and published by Wiley-TMS. This book was released on 2016-10-03 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book contains the Proceedings 13th International Symposium on Superalloys

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.

Download or read book Microstructure Sensitive Notch Root Analysis for Ni Base Superalloys Preprint written by and published by . This book was released on 2007 with total page 26 pages. Available in PDF, EPUB and Kindle. Book excerpt: Macroscopic viscoplastic constitutive models for y-y Ni-base superalloys typically do not contain an explicit dependence on the underlying microstructure. Microstructure dependent models are of interest since the sizes, volume fractions, and morphologies of primary, secondary, and tertiary precipitates can substantially affect the stress-strain response. The principle microstructural features that can significantly affect the stress-strain response of y-y Ni-base superalloys are the grain size and precipitate volume fraction and size distributions. An Artificial Neural Network (ANN) is used to correlate the material parameters in an internal state variable cyclic viscoplasticity model with these microstructure plasticity calculations performed on other microstructures within the range characterized experimentally. The trained model is applied to an example of component notch root analyses to explore the potential impact of microstructure-sensitive constitutive models in fatigue design of structures.

Download or read book Ni Based Superalloys written by James Coakley and published by Trans Tech Publications Ltd. This book was released on 2020-07-28 with total page 720 pages. Available in PDF, EPUB and Kindle. Book excerpt: Aggregated Book

Download or read book The Microstructure of Superalloys written by Madeleine Durand-Charre and published by Routledge. This book was released on 2017-11-22 with total page 139 pages. Available in PDF, EPUB and Kindle. Book excerpt: Presents all the main aspects of the microstructure of nickel-base superalloys, and includes micrographs chosen from among a large range of commercial and academic alloys, from the as-cast product to in-situ components, worn from in-service use. Including more than 100 illustrations, the text explains all the transformation mechanisms involved in the origination (creation) of microstructures during solidification or heat treatments (crystallization paths, segregation, crystal orientation, precipitation, TCP, coarsening and rafting, etc.). It includes up-to-date information and data such as phase diagrams, crystallographic structures, and relationships with functional properties. Nearly 300 references provide a key to further investigation.

Download or read book Microstructural Evolution and Deformation Mechanisms in Nickel base Super Alloys written by Hyo-jin Song and published by . This book was released on 2010 with total page 210 pages. Available in PDF, EPUB and Kindle. Book excerpt: Nickel-base superalloys are used at high temperature applications in aerospace and power generation. The objective of present work is to gain a better understanding of microstructural evolution and deformation mechanisms in Nickel-base superalloys. The microstructure of the Nickel base superalloy is basically composed of gamma matrix with eta, delta, gamma prime or gamma double prime/or both, carbides and nitrides. Cold working of IN 718 and Waspaloy to 50% reduction led to an increase in hardness. This hardening was related to the continuous increase in dislocation density in both alloys. Cold working of IN 718 to levels of 10% and higher also led to shearing of the gamma double prime precipitates present initially, leading to their dissolution and the redistribution of the alloying elements into the matrix. Shot peening of both alloys introduces near surface compressive residual stresses and a significant increase in the surface and near-surface hardness to a distance of ~200-400 [mu]m in both alloys. Shot peening of both alloys followed by aging at 900°C quickly led to a large drop in hardness to near that of the bulk material. Aging shot peened the IN 718 at 700°C led to an increase in the hardness throughout the sample. Microstructural characterization revealed that this hardening is related to the formation of new precipitates of gamma prime or gamma double prime or both within the gamma matrix. Aging shot peened Waspaloy at 700°C led to an increase or decrease at near surface region at short time, depending on the Almen intensity. Microstructural characterization shows that these changes are related to partial reduction in % cold work by recrystallization and/or new gamma prime precipitation, depending on the Almen intensity. The hardening, microstructural evolution and stress rupture behavior of IN 740 were studied. Aging of the IN 740 alloy led to significant hardening due to the gamma prime precipitation. The gamma prime coarsening in aged and tensile tested and stress rupture tested IN740 alloy was observed to follow the LSW theory. Gamma prime coarsening was promoted by the applied stress and accelerated between 750 and 800°C. Applied stress was also found to significantly enhance the eta phase formation. Various models for strengthening in Ni-base superalloys were considered and their contributions to strength following aging were calculated utilizing the experimentally measured gamma prime sizes and volume fractions. Good agreement between the calculated and experimentally measured yield strengths was obtained. Based on these calculations and characterization of the deformation microstructure in the aged and tensile-tested samples, it was concluded that apart from solid solution strengthening, the main strengthening contributions from the gamma prime precipitates is associated with precipitate shearing involving either weak pair dislocation coupling or strong pair dislocation coupling/ or both at 700°C for 100h, strong pair dislocation coupling following aging at 700°C for 1000, 3000h and 750°C for 100, 1000h, strong pair coupling or Orowan process/or both following aging at 750°C for 3000h and 800°C for 100h, and mainly Orowan process following aging at 800°C for 1000 and 3000h.

Download or read book Characterization of a Nickel base Superalloy Through Electrical Resistivity microstructure Relationships Facilitated by Small Angle Scattering written by Ricky Lee Whelchel and published by . This book was released on 2011 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Nickel-base superalloys obtain high temperature mechanical properties through formation of precipitate phases formed via heat treatment. The precipitate microstructure evolves with heat treatment or thermal exposure, which can lead to degrading mechanical properties. This project focuses on the use of electrical resistivity as a non-destructive testing method to monitor the precipitate phase in Waspaloy (a polycrystalline nickel-base superalloy). The evolution of the precipitate microstructure is characterized throughout the volume of the specimens using both small angle neutron scattering (SANS) and ultra small angle X-ray scattering (USAXS) measurements. These measurements are also aided by microscopy and X-ray diffraction measurements.