Download or read book Thermomechanical Training and Characterization of Ni Ti Hf and Ni Ti Hf Cu High Termperature Shape Memeory Alloys written by Chantz Michael Denowh and published by . This book was released on 2011 with total page 206 pages. Available in PDF, EPUB and Kindle. Book excerpt: Nickel-Titanium (NiTi) is the most commonly used Shape Memory Alloy (SMA) for actuator applications. Typical SMA actuators use changes in temperature to initiate solid to solid phase transformations resulting in macroscopic material deformations; though NiTi is limited to temperature changes below 100°C. This eliminates high temperature applications of NiTi actuators. To expand the design window of SMAs, many high temperature NiTi based SMAs have been developed by adding ternary elements to the NiTi matrix. The additions result in degradation of the shape memory behaviors and their usefulness as actuators is still in question. The purpose of this research is to characterize and train two recently developed high temperature SMAs, NiTi 29.--Hf 20 and NiCu 5Ti 29.--Hf 20, to determine their effectiveness as linear actuators. Shape memory effect (SME) and superelastic tests were used to characterize the materials behavior followed by thermomechanical training at a constant stress. The SME test resulted in no martensite detwinning plateau and a non-linear stress-strain curve implying the simultaneous occurrence of slip and martensite reorientation. The superelastic tests also show an austenitic yield stress above 600 MPa. Thermomechanical training resulted in small amounts of plastic strain growth, and the development of two-way shape memory (TWSM). The TWSM results were fitted using the Bo & Lagoudas model, and is capable of predicting the actuation strains at other stresses. The results support the conclusion that hafnium distorts martensite slip planes, and (Ti, Hf) 2Ni and (Ti, Hf) 3Ni 4 precipitates form during aging and annealing. The distorted slip planes cause slip and martensite reorientation to occur simultaneously. This develops a strong stress field during training within the first few cycles. The stress field develops TWSM, but limits further plastic growth and TWSM development. The precipitate formation increases material strength, as seen in the superelastic loading, but also embrittles the material. Thermomechanical training of an annealed specimen resulted in a brittle failure after several thermal cycles due to the growth of particulate size during annealing. The two alloys are ideally suited for high temperature actuators. TWSM was trained into the material and the transformation temperatures are higher than that of NiTi, but low enough to avoid annealing and problematic creep temperatures.
Download or read book Characterization of Ni RICH NiTiHf Based High Temperature Shape Memory Alloys written by Gurdish S. Ded and published by . This book was released on 2010 with total page 210 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Shape Memory Alloys 2017 written by Takuo Sakon and published by MDPI. This book was released on 2018-03-15 with total page 193 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book is a printed edition of the Special Issue Shape Memory Alloys 2017" that was published in Metals
Download or read book Shape Memory Alloys written by M. Fremond and published by Springer. This book was released on 2014-05-04 with total page 152 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book consists of two chapters. The first chapter deals with the thermomechanical macroscopic theory describing the transformation and deformation behavior of shape memory alloys. The second chapter deals with the extensive and fundamental review of the experimental works which include crystallography, transformations and mechanical characteristics in Ti-Ni, Cu-base and ferrous shape memory alloys.
Download or read book Thermomechanical Characterization of Nickel Titanium Copper Shape Memory Alloy Films written by KP. Seward and published by . This book was released on 2001 with total page 13 pages. Available in PDF, EPUB and Kindle. Book excerpt: In an effort to develop a more extensive model for the thermomechanical behavior of shape memory alloy (SMA) films, a novel characterization method has been developed. This automated test has been tailored to characterize films for use in micro-electromechanical system (MEMS) actuators. The shape memory effect in NiTiCu is seen in the solid-state phase transformation from an easily deformable low-temperature state to a "shape remembering" high-temperature state. The accurate determination of engineering properties for these films necessitates measurements of both stress and strain in microfabricated test structures over the full range of desired deformation. Our various experimental methods (uniaxial tensile tests, bimorph curvature tests, and diaphragm bulge tests) provide recoverable stress and strain data and the stress-strain relations for these films. Tests were performed over a range of temperatures by resistive heating or ambient heating. These measurements provide the results necessary for developing active SMA structural film design models.
Download or read book Characterization of Stoichiometric and Aging Effects on NiTiHf High Temperature Shape Memory Alloys written by Daniel Robert Coughlin and published by . This book was released on 2013 with total page 153 pages. Available in PDF, EPUB and Kindle. Book excerpt: Certain microstructure and mechanical properties are obtained when Hf is added to NiTi and a proper aging cycle is used. Results from isothermal compression tests that were executed above the austenite finish temperature determined that the Ni-rich NiTiHf alloys exhibited all the necessary properties to be considered for HTSMA applications. The test temperature range of the isothermal compression tests were chosen to characterize the transition from PE behavior to austenite plasticity and to examine the deformation behavior of the B2 phase at high temperatures.
Download or read book Shape Memory Alloys written by Dimitris C. Lagoudas and published by Springer Science & Business Media. This book was released on 2008-06-05 with total page 446 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book provides a working knowledge of the modeling and engineering applications of shape memory alloys (SMAs), beginning with a rigorous introduction to continuum mechanics and continuum thermodynamics as they relate to the development of SMA modeling.Modern SMAs can recover from large amounts of bending and deformation, and millions of repetitions within recoverable ranges. SMAs are used in the medical industry to create stents, in the dental industry to create dental and orthodontic archwires, and in the aerospace industry to create fluid fittings. The text presents a unified approach to the constitutive modeling of SMAs, including modeling of magnetic and high temperature SMAs.
Download or read book Laser Material Processing written by William M. Steen and published by Springer Science & Business Media. This book was released on 2013-04-18 with total page 416 pages. Available in PDF, EPUB and Kindle. Book excerpt: New chapters on bending and cleaning reflect the changes in the field since the last edition, completing the range of practical knowledge about the processes possible with lasers already familiar to users of this well-known text. Professor Steen's lively presentation is supported by a number of original cartoons by Patrick Wright and Noel Ford, which will bring a smile to your face and ease the learning process. From the reviews: "...well organized, and the text is very practical...The engineering community will find this book informative and useful." (OPTICS AND PHOTONICS NEWS, July/August 2005)
Download or read book Shape Memory Alloys written by Francisco Manuel Braz Fernandes and published by BoD – Books on Demand. This book was released on 2013-04-03 with total page 294 pages. Available in PDF, EPUB and Kindle. Book excerpt: 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.
Download or read book NiTiHf High Temperature Shape Memory Alloy Design with the Assistance of Machine Learning written by Aysel Aysu Çatal and published by . This book was released on 2022 with total page 114 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Ni free Ti based Shape Memory Alloys written by Hee Young Kim and published by Butterworth-Heinemann. This book was released on 2018-09-17 with total page 222 pages. Available in PDF, EPUB and Kindle. Book excerpt: Ni-free Ti-based Shape Memory Alloys reviews the fundamental issues of biomedical beta-type Ti base shape memory and superelastic alloys, including martensitic transformation, shape memory and superelastic properties, alloy development, thermomechanical treatment and microstructure control, and biocompatibility. Some unique properties, such as large nonlinear elastic behavior and low Young's modulus, observed in metastable Ti alloys are discussed on the basis of phase stability. As it is expected that superelastic Ti alloys will further expand the applications of shape memory alloys within the biomedical field, this book provides a comprehensive review of these new findings in Ti-base shape memory and superelastic alloys. - Includes coverage of phase transformations in titanium alloys - Discusses mechanical properties and alloy development - Presents a review of Ti-based shape alloys and their applications
Download or read book A Study on NiTiSn Low Temperature Shape Memory Alloys and the Processing of NiTiHf High Temperature Shape Memory Alloys written by Avery W. Young and published by . This book was released on 2018 with total page 68 pages. Available in PDF, EPUB and Kindle. Book excerpt: Shape memory alloys (SMAs) operating as solid-state actuators pose economic and environmental benefits to the aerospace industry due to their lightweight, compact design, which provides potential for reducing fuel emissions and overall operating cost in aeronautical equipment. Despite wide applicability, the implementation of SMA technology into aerospace-related actuator applications is hindered by harsh environmental conditions, which necessitate extremely high or low transformation temperatures. The versatility of the NiTi-based SMA system shows potential for meeting these demanding material constraints, since transformation temperatures in NiTi can be significantly raised or lowered with ternary alloying elements and/or Ni:Ti ratio adjustments. In this thesis, the expansive transformation capabilities of the NiTi-based SMA system are demonstrated with a low and high-temperature NiTi-based SMA; each encompassing different stages of the SMA development process. First, exploratory work on the NiTiSn SMA system is presented. The viability of NiTiSn alloys as low-temperature SMAs (LTSMAs) was investigated over the course of five alloy heats. The site preference of Sn in near-equiatomic NiTi was examined along with the effects of solution annealing, Ni:Ti ratio adjustments, and precipitation strengthening on the thermomechanical properties of NiTiSn LTSMAs. Second, the thermomechanical processability of NiTiHf high-temperature SMA (HTSMA) wires is presented. The evolution of various microstructural features (grain size reduction, oxide growth, and nano-precipitation) were observed at incremental stages of the hot rolling process and linked to the thermal and mechanical responses of respective HTSMA rods/wires. This work was carried out in an effort to optimize the rolling/drawing process for NiTiHf HTSMAs.
Download or read book SMST 2000 written by Scott M. Russell and published by ASM International. This book was released on 2001-01-01 with total page 695 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Design of Shape Memory Alloy SMA Actuators written by Ashwin Rao and published by Springer. This book was released on 2015-05-08 with total page 137 pages. Available in PDF, EPUB and Kindle. Book excerpt: This short monograph presents an analysis and design methodology for shape memory alloy (SMA) components such as wires, beams, and springs for different applications. The solid-solid, diffusionless phase transformations in thermally responsive SMA allows them to demonstrate unique characteristics like superelasticity and shape memory effects. The combined sensing and actuating capabilities of such materials allows them to provide a system level response by combining multiple functions in a single material system. In SMA, the combined mechanical and thermal loading effects influence the functionality of such materials. The aim of this book is to make the analysis of these materials accessible to designers by developing a "strength of materials" approach to the analysis and design of such SMA components inspired from their various applications with a review of various factors influencing the design process for such materials.
Download or read book Characterization of High Temperature Shape Memory Alloys in the Ni Ti Pt Ternary System written by Grant A. Hudish and published by . This book was released on 2009 with total page 68 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Effects of Thermo mechanical Treatment on the Shape Memory Behavior of NiTi and CoNiAl Alloys written by Haluk Ersin Karaca and published by . This book was released on 2004 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Nickel-Titanium (NiTi) shape memory alloys have been the focus of extensive research due to its unique characteristics such as high recoverable strain and ductility. However, solutionized samples of NiTi do not demonstrate good shape memory characteristics due to low strength for dislocation slip. Thermo-mechanical treatments are required to strengthen the matrix and improve the shape memory characteristics. Plastic deformation and the subsequent annealing is the common way to improve shape memory properties. In this case, deformation magnitude, temperature, rate, mechanism, and annealing temperature and time are all important parameters for the final shape memory properties. Equal channel angular extrusion (ECAE) is a well-known technique to severely deform materials by simple shear with no change in cross-section. In this study, Ti- 49.8 at% Ni samples are deformed by ECAE at three different temperatures near transformation temperatures. X-ray analysis, calorimetry, transmission electron microscopy and thermo-mechanical cycling techniques are utilized to investigate the effects of severe deformation and subsequent annealing treatment on shape memory properties. Martensite stabilization, formation of strain induced B2 phase, change in transformation temperatures, formation of new phases, recrystallization temperature, texture formation, and increase in strength and pseudoelastic strain are the main findings of this study. Co-32.9 at% Ni-29.5 at% Al is a newly found ferromagnetic alloy. Its low density, high melting temperature and cheap constituents make the alloy advantageous among other shape memory alloys. Although some magnetic properties of this alloy are known, there is no report on basic shape memory characteristics of CoNiAl. In this study, effect of thermo-mechanical treatments on the microstructure and shape memory characteristics such as transformation behavior, pseudoelasticity, stages of transformation, temperature dependence of the pseudoelasticity, response to thermal and stress cycling is investigated. Formation of second phase along the grain boundaries and inside the grains, about 4% pseudoelastic and two-way shape memory strain, very narrow stress hysteresis, large pseudoelastic window (>150ʻC), two-stage martensitic transformation, stable response to cyclic deformation, high strength for dislocation slip, slope of Clasius-Clapeyron curve, and twinning plane are determined for the first time in literature.
Download or read book Metals Abstracts written by and published by . This book was released on 1998 with total page 1042 pages. Available in PDF, EPUB and Kindle. Book excerpt:
