On the Mesoscale Plasticity of Nickel-base Superalloy Single Crystals PDF Download

Author: Siqi Ying
Publisher:
ISBN:
Category :
Languages : en
Pages :

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Author: Loeïz Nazé
Publisher: Elsevier
ISBN: 0128193581
Category : Technology & Engineering
Languages : en
Pages : 612

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Book Description
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

Author: Christine Dianne Allan
Publisher:
ISBN:
Category :
Languages : en
Pages : 420

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Author: W. Steven Johnson
Publisher:
ISBN:
Category : Angled pre-crack
Languages : en
Pages : 13

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An important application of nickel base superalloys is in the industrial gas turbine (IGT) industry, where the high temperature capabilities of these alloys are exploited. Extensive testing has focused on the tensile and fatigue properties of single crystal versions of these alloys. The single crystals are utilized in the hottest parts of the turbine, where a detailed knowledge of material behavior is critical to design and life assessment. However, studies on the effects of temperature on fracture toughness have largely been absent in both past and present literature. Therefore, the goal of this research is to characterize the fracture toughness properties of a second-generation single crystal nickel superalloy at elevated temperatures. The experimental methods follow ASTM guidelines, as does the analysis for the elastic (K) and plastic (J integral) deformation. The toughness values were invalid for plain strain fracture toughness, but this should be expected from a structural material. In spite of this fact, both the K- and J- based analyses reveal consistent trends. Increased plasticity at elevated temperatures results in an overall increase in toughness as temperature increases. Unusual cases with inclined pre-cracks and microstructural defects did not technically yield valid results, although they were consistent with the nominal cases. Overall, the results indicate that the toughness of single crystal nickel alloys is actually quite high. Thus, the lack of work in this subject is understandable. However, it would seem that any design and lifing work would benefit from an understanding of such a fundamental property.

Author: Tresa Mader Pollock
Publisher:
ISBN:
Category :
Languages : en
Pages : 322

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Author: Franz Roters
Publisher: John Wiley & Sons
ISBN: 3527642099
Category : Technology & Engineering
Languages : en
Pages : 188

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Written by the leading experts in computational materials science, this handy reference concisely reviews the most important aspects of plasticity modeling: constitutive laws, phase transformations, texture methods, continuum approaches and damage mechanisms. As a result, it provides the knowledge needed to avoid failures in critical systems udner mechanical load. With its various application examples to micro- and macrostructure mechanics, this is an invaluable resource for mechanical engineers as well as for researchers wanting to improve on this method and extend its outreach.

Author: Kijoon Yu
Publisher:
ISBN:
Category :
Languages : en
Pages : 314

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Author: Sanjay Puri
Publisher: CRC Press
ISBN: 1420008366
Category : Science
Languages : en
Pages : 356

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Providing a comprehensive introduction with the necessary background material to make it accessible for a wide scientific audience, Kinetics of Phase Transitions discusses developments in domain-growth kinetics. This book combines pedagogical chapters from leading experts in this area and focuses on incorporating various experimentally releva

Author:
Publisher:
ISBN:
Category :
Languages : en
Pages : 96

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Interrupted tensile tests were conducted to fixed plastic strain levels in 001 oriented single crystals of the nickel-base superalloys PWA 1480. Testing was done in the range from 20-1093 C, at strain rates of 0.5 and 50%/min. The yield strength was constant from 20-760 C, above which the strength dropped rapidly and became a strong function of strain rate. The high temperature data could be represented very well by an Arrhenius-type equation, which resulted in three distinct temperature regimes. The deformation substructures could be grouped in the same three regimes.

Author: Christian Busse
Publisher: Linköping University Electronic Press
ISBN: 9176853950
Category :
Languages : en
Pages : 26

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This Licentiate of Engineering thesis is a product of the results generated in the research project KME-702, which comprises modelling, microstructure investigations and material testing of cast nickel-base superalloys. The main objective of this work is to model the fatigue crack propagation behaviour in single-crystal nickel-base superalloys. To achieve this, the influence of the crystal orientations on the cracking behaviour is assessed. The results show that the crystal orientation is strongly affecting the material response and must be accounted for. Furthermore, a linear elastic crack driving force parameter suitable for describing crystallographic cracking has been developed. This parameter is based on resolved anisotropic stress intensity factors and is able to predict the correct crystallographic cracking plane after a transition from a Mode I crack. Finally, a method to account for inelastic deformations in a linear elastic fracture mechanics context was investigated. A residual stress field is extracted from an uncracked finite-element model with a perfectly plastic material model and superimposed on the stress field from the cracked model with a linear elastic material model to account for the inelastic deformations during the determination of the crack driving force. The modelling work is validated by material testing on two different specimen geometries at different temperatures. This Licentiate of Engineering thesis consists of two parts, where Part I gives an introduction and background to the research area, while Part II consists of three papers. Denna licentiatavhandling är en produkt av resultat som genererats i forskningsprojektet KME-702, och omfattar modellering, mikrostrukturundersökningar och materialprovning av gjutna nickelbaserade superlegeringar. Huvudsyftet med detta arbete är att modellera sprickförloppet under utmattning i enkristallina nickelbaserade superlegeringar. För att uppnå detta har kristallorienteringens inverkan på sprickbeteendet utvärderats. Resultaten visar att kristallorienteringen har en stark inverkan på materialbeteendet, således måste hänsyn till denna tas. Dessutom har en linjär-elastisk sprickdrivkraftsparameter lämplig att beskriva kristallografisk sprickbildning utvecklats. Denna parameter är baserad på anisotropa spänningsintensitetsfaktorer på kristallplan och kan prediktera det korrekta kristallografiska sprickplanet efter övergång från Modus I spricka. Slutligen har undersökts en metod för att ta hand om inelastiska deformationer i en linjär-elastisk brottmekanikskontext. Ett restspänningsfält extraherades från en osprucken finita element modell med en ideal plastisk materialmodell. Denna överlagrades på spänningsfältet från den spruckna modellen, som analyserades med en linjär-elastisk materialmodell, för att ta hänsyn till de inelastiska deformationerna vid bestämning av sprickdrivkraften. Modelleringsarbetet validerades genom materialprovning på två olika provgeometrier vid olika temperaturer. Licentiatavhandlingen består av två delar, där del I ger en introduktion och bakgrund till forskningsområdet medan del II består av tre papper. Dieses Lizentiat der Ingenieurwissenschaften ist im Rahmen des Forschungsprojekts KME-702 entstanden, welches Modellierung, Mikrostrukturuntersuchungen und Materialtests von gegossenen nickelbasierten Superlegierungen umfasst. Das Hauptziel dieser Arbeit ist die Modellierung der Ermüdungsrissausbreitung in einkristallinen nickelbasierten Superlegierungen. Um dieses zu erreichen, wurde der Einfluss der Kristallorientierungen auf das Rissverhalten untersucht. Die Ergebnisse zeigen, dass die Kristallorientierung das Materialverhalten stark beeinflusst und daher berücksichtigt werden muss. Darüber hinaus wurde ein linear elastischer Rissantriebskraftparameter entwickelt, der zum Beschreiben von kristallographischen Rissen geeignet ist. Dieser Parameter basiert auf aufgelösten anisotropen Spannungsintensitätsfaktoren und ist in der Lage, die korrekte kristallographische Rissebene nach einem Übergang von einem Modus I Riss vorherzusagen. Abschließend wird in einem linear-elastisch bruchmechanischen Kontext eine Methode untersucht, die nichtelastischen Deformationen bei der Bestimmung der Rissantriebskraft zu berücksichtigen. Dazu wird aus einem Finite-Elemente Modell, welches keinen Riss aufweist und mit einem perfekt plastischen Materialmodell beschrieben wird, das Restspannungsfeld extrahiert und dem Spannungsfeld überlagert, welches aus dem Modell mit Riss unter Verwendung eines linear elastischen Materialmodells erzeugt wurde. Die Modellierung wird durch Materialtests an zwei verschiedenen Probengeometrien bei unterschiedlichen Temperaturen validiert. Dieses Lizentiat der Ingenieurwissenschaften besteht aus zwei Teilen, wobei Teil I eine Einführung und einen Hintergrund in das Forschungsgebiet gibt, während Teil II aus drei Forschungsartikeln besteht.