Martensitic Phase Transformation of NiTi-based Shape Memory Alloys

Martensitic Phase Transformation of NiTi-based Shape Memory Alloys PDF Author: Magdalena M. Parlinska-Wojtan
Publisher:
ISBN:
Category :
Languages : en
Pages : 147

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Martensitic Phase Transformation of NiTi-based Shape Memory Alloys

Martensitic Phase Transformation of NiTi-based Shape Memory Alloys PDF Author: Magdalena M. Parlinska-Wojtan
Publisher:
ISBN:
Category :
Languages : en
Pages : 147

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Book Description


Martensitic Phase Transformation of NiTi-based Shape Memory Alloys

Martensitic Phase Transformation of NiTi-based Shape Memory Alloys PDF Author: Magdalena M. Parlinska-Wojtan (Materialwissenschaftlerin.)
Publisher:
ISBN:
Category :
Languages : en
Pages : 147

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Book Description


Magnetism and Structure in Functional Materials

Magnetism and Structure in Functional Materials PDF Author: Antoni Planes
Publisher: Springer Science & Business Media
ISBN: 3540316310
Category : Science
Languages : en
Pages : 261

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Book Description
Magnetism and Structure in Functional Materials addresses three distinct but related topics: (i) magnetoelastic materials such as magnetic martensites and magnetic shape memory alloys, (ii) the magnetocaloric effect related to magnetostructural transitions, and (iii) colossal magnetoresistance (CMR) and related manganites. The goal is to identify common underlying principles in these classes of materials that are relevant for optimizing various functionalities. The emergence of apparently different magnetic/structural phenomena in disparate classes of materials clearly points to a need for common concepts in order to achieve a broader understanding of the interplay between magnetism and structure in this general class of new functional materials exhibiting ever more complex microstructure and function. The topic is interdisciplinary in nature and the contributors correspondingly include physicists, materials scientists and engineers. Likewise the book will appeal to scientists from all these areas.

Engineering Aspects of Shape Memory Alloys

Engineering Aspects of Shape Memory Alloys PDF Author: T W Duerig
Publisher: Butterworth-Heinemann
ISBN: 1483144755
Category : Technology & Engineering
Languages : en
Pages : 512

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Book Description
Engineering Aspects of Shape Memory Alloys provides an understanding of shape memory by defining terms, properties, and applications. It includes tutorials, overviews, and specific design examples—all written with the intention of minimizing the science and maximizing the engineering aspects. Although the individual chapters have been written by many different authors, each one of the best in their fields, the overall tone and intent of the book is not that of a proceedings, but that of a textbook. The book consists of five parts. Part I deals with the mechanism of shape memory and the alloys that exhibit the effect. It also defines many essential terms that will be used in later parts. Part II deals primarily with constrained recovery, but to some extent with free recovery. There is an introductory paper which defines terms and principles, then several specific examples of products based on constrained recovery. Both Parts III and IV deal with actuators. Part III introduces engineering principles while Part IV presents several of the specific examples. Finally, Part V deals with superelasticity, with an introductory paper and then several specific examples of product engineering.

Direct Methods in the Calculus of Variations

Direct Methods in the Calculus of Variations PDF Author: Bernard Dacorogna
Publisher: Springer Science & Business Media
ISBN: 3642514405
Category : Mathematics
Languages : en
Pages : 312

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Book Description
In recent years there has been a considerable renewal of interest in the clas sical problems of the calculus of variations, both from the point of view of mathematics and of applications. Some of the most powerful tools for proving existence of minima for such problems are known as direct methods. They are often the only available ones, particularly for vectorial problems. It is the aim of this book to present them. These methods were introduced by Tonelli, following earlier work of Hilbert and Lebesgue. Although there are excellent books on calculus of variations and on direct methods, there are recent important developments which cannot be found in these books; in particular, those dealing with vector valued functions and relaxation of non convex problems. These two last ones are important in appli cations to nonlinear elasticity, optimal design . . . . In these fields the variational methods are particularly effective. Part of the mathematical developments and of the renewal of interest in these methods finds its motivations in nonlinear elasticity. Moreover, one of the recent important contributions to nonlinear analysis has been the study of the behaviour of nonlinear functionals un der various types of convergence, particularly the weak convergence. Two well studied theories have now been developed, namely f-convergence and compen sated compactness. They both include as a particular case the direct methods of the calculus of variations, but they are also, both, inspired and have as main examples these direct methods.

Shape Memory Alloys

Shape Memory Alloys PDF Author: Francisco Manuel Braz Fernandes
Publisher: BoD – Books on Demand
ISBN: 9535110845
Category : Science
Languages : en
Pages : 294

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Book Description
Shape memory alloys have become in the past decades a well established research subject. However, the complex relations between properties and structure have created a continuously growing interest for a deeper insight all this time. The complexity of relationships between structure and properties is mostly related to the fact that strong ?multidimensional? interactions are taking place: from the early studies focusing on the thermal and/or mechanical induced phase transformations to the more recent findings on the magnetically induced structural changes. On the other hand, these singular behavioral characteristics have driven a great industrial interest due to the innovative aspects that the applications of shape memory alloys may provide. This makes this subject a highly attractive source of continuous studies, ranging from basics crystallography and thermodynamics to mechanical analysis and electrical and magnetic properties characterization. In this book, a group of recent studies is compiled focusing on a wide range of topics from processing to the relationship between the structure and properties, as well as new applications.

Shape-Memory Alloys Handbook

Shape-Memory Alloys Handbook PDF Author: Christian Lexcellent
Publisher: John Wiley & Sons
ISBN: 1118577957
Category : Technology & Engineering
Languages : en
Pages : 295

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Book Description
The aim of this book is to understand and describe the martensitic phase transformation and the process of martensite platelet reorientation. These two key elements enable the author to introduce the main features associated with the behavior of shape-memory alloys (SMAs), i.e. the one-way shape-memory effect, pseudo-elasticity, training and recovery. Attention is paid in particular to the thermodynamical frame for solid materials modeling at the macroscopic scale and its applications, as well as to the particular use of such alloys – the simplified calculations for the bending of bars and their torsion. Other chapters are devoted to key topics such as the use of the “crystallographical theory of martensite” for SMA modeling, phenomenological and statistical investigations of SMAs, magneto-thermo-mechanical behavior of magnetic SMAs and the fracture mechanics of SMAs. Case studies are provided on the dimensioning of SMA elements offering the reader an additional useful framework on the subject. Contents 1. Some General Points about SMAs. 2. The World of Shape-memory Alloys. 3. Martensitic Transformation. 4. Thermodynamic Framework for the Modeling of Solid Materials. 5. Use of the “CTM” to Model SMAs. 6. Phenomenological and Statistical Approaches for SMAs. 7. Macroscopic Models with Internal Variables. 8. Design of SMA Elements: Case Studies. 9. Behavior of Magnetic SMAs. 10. Fracture Mechanics of SMAs. 11. General Conclusion. Appendix 1. Intrinsic Properties of Rotation Matrices. Appendix 2. “Twinning Equation” Demonstration. Appendix 3. Calculation of the Parameters a, n and Q from the “Twinning” Equation. Appendix 4. “Twinned” Austenite/Martensite Equation. About the Authors Christian Lexcellent is Emeritus Professor at the École National Supérieure de Mécanique et des Microtechniques de Besançon and a researcher in the Department of Applied Mechanics at FEMTO-ST in France. He is a specialist in the mechanics of materials and phase transition and has taught in the subjects of mechanics of continuum media and shape memory alloys. He is also a member of the International Committee of ESOMAT.

Microstructure of Martensite

Microstructure of Martensite PDF Author: Kaushik Bhattacharya
Publisher: Oxford University Press
ISBN: 9780198509349
Category : Computers
Languages : en
Pages : 308

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Book Description
Martensites are crystalline solids that display dazzling patterns at the microscopic scales. This microstructure gives rise to unusual macroscopic properties like the shape-memory effect. Starting with the crystalline structure, this book describes a theoretical framework for studying martensites and uses the theory to explain why these materials form microstructure. The macrostructure consequences of the microstructure are subsequently discussed. Complete with a piece of shape-memory wire and numerous examples from real materials, this book represents a successful case study in multiscale modeling, giving a clear understanding of the link between microstructure and macrostructure properties. Beautifully written, in a most clear and pedagogical manner, it holds appeal for a broad audience. On the one hand, it introduces modern modeling techniques to those trained in materials science, mechanics and physics and shows how these techniques can be used in real-world problems. On the other hand, it introduces physical phenomena to those trained in mathematics, and demonstrates how such phenomena give rise to interesting mathematical problems.

Niti-based Shape Memory Alloys

Niti-based Shape Memory Alloys PDF Author: Asheesh Lanba
Publisher:
ISBN:
Category :
Languages : en
Pages :

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Book Description
This work aims to experimentally establish processing-structure-property relationships in wide-hysteresis NiTiNb shape memory alloys. Manufactures supplied custom composition cast materials and off-the-shelf deformation processed (i.e. small diameter rods and thin sheets) NiTiNb alloys, and thus different extents of processing are studied. Microstructure characterization of these materials highlights the impact of processing on micro-constituent morphology. Thermo-mechanical experiments are conducted in order to contrast the mechanical and shape memory properties. Micro-deformation measurements are employed to visualize strain localization associated with the differently processed microstructures. Mechanistic and phenomenological rationale are developed that correlate the micro-constituent morphology and its interaction with the underlying martensitic phase transformation to the mechanical and shape memory behavior.The cast and deformation-processed NiTiNb microstructures are characterized via electron and acoustic microscopy. The microstructures are also altered via annealing. The cast microstructure reveals that the addition of Nb as a ternary element in NiTi results in a microstructure with [beta] particles which are primarily Nb in a eutectic mixture with the [alpha] NiTi(Nb) phase. The eutectic mixture is cellular-like with areas of [alpha] NiTi(Nb) matrix material in between. The martensitic transformation, which is a reversible diffusionless crystallographic phase change that can be thermally- or stress-induced between a high temperature austenitic phase and low temperature martensitic phase, only takes place in this matrix. Two different deformation-processed alloys are studied; a rolled sheet and an extruded rod. Deformation-processing breaks up the eutectic structure resulting in a composite microstructure with discontinuous aligned second phase Nb-rich [beta]-particle reinforcements. Annealing causes the Nb-rich particles to grow, and also increases the inter-particle spacing in both cast and deformation processed alloys.The shape memory behavior, characterized via thermal cycling with and without an external stress, and the mechanical properties, characterized from isothermal deformation to failure at different temperatures, are contrasted for cast and deformation-processed microstructures. The stress-free thermal cycling allows us to establish the characteristic transformation temperatures along with the elastic and irreversible energies associated with the transformation. Thermal cycling under load is used to characterize the transformation temperatures, thermal hysteresis, and the recoverable and permanent deformations. The isothermal deformation is used to contrast the stress-induced transformation and subsequent plastic deformation using the critical transformation stress and strain, elastic moduli, yield stress, and strain at failure. The work finds the experimental evidence correlating strain energy relaxation and widening of hysteresis and reverse transformation temperature interval.This comparative study between the cast and deformation processed alloys is augmented by undertaking a multi-scale deformation analysis including digital image correlation to measure micro-scale strain localizations. The strain localizations are characterized in-situ, and allow the comparison of the impact of different micro-constituents on the evolution of localized deformations during the stress-induced transformation and shape memory recovery. Localized regions of high strain accompany the stress-induced transformation in cast alloys that lead to fracture, whereas the stress-induced transformation region in processed alloys has no such strain concentrations.The micro-constituent morphology in both the cast and deformation-processed alloys cause martensite stabilization, however the deformation processed microstructure promotes larger irreversibility and shows evidence of strain energy relaxation that is missing in cast alloys. The eutectic boundaries in the cast microstructure likely prohibit interaction of the martensitic transformation with the particles, and promote large strain localizations during the stress-induced transformation. Such boundaries are missing in the deformation-processed composite microstructure, and thus the particles interact more with the martensitic transformation that leads to the larger irreversibility, improved ductility and better mechanical properties.

Smart Structures Theory

Smart Structures Theory PDF Author: Inderjit Chopra
Publisher: Cambridge University Press
ISBN: 052186657X
Category : Science
Languages : en
Pages : 925

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Book Description
This book focuses on smart materials and structures, which are also referred to as intelligent, adaptive, active, sensory, and metamorphic. The ultimate goal is to develop biologically inspired multifunctional materials with the capability to adapt their structural characteristics, monitor their health condition, perform self-diagnosis and self-repair, morph their shape, and undergo significant controlled motion.