Applications Of Shape Memory Alloys Research Articles

Ni-Mn-Al Heusler Alloy Samples Preparation by Mechanical Alloying Method and Study of their Investigated Properties

Objective: In this work, ternary Ni-Mn-Al Heusler alloy powder samples were fabricated using mechanical alloying technique to study its alloy formation mechanism and the effects of mechanical alloying on the investigated properties. Methods: The samples were prepared using high energy planetary ball mill under argon conditions. The milling time of 0 h (hour/hours), 5 h, 10 h and 15 h were selected to see the progress of alloy formation. The microstructural, compositional, thermal and magnetic studies of ball milled powder samples were conducted. Findings: Compositional study reveals stoichiometric Heusler composition (X2YZ) of Ni-Mn-Al alloy with no contamination. The optimum milling time required for the formation of alloy by mechanical alloying resulted through the proper selection of milling parameters. The average crystallite size obtained reveals that nanocrystalline structure of Ni-Mn-Al alloy was achieved during the ball milling operation. The successive heating of powder particles in differential scanning calorimetry showed crystallization and alloy formation. Novelty/Applications: The magnetic study indicated soft ferromagnetic nature of the selected ball milled powder sample suggesting the alloy can be developed for possible ferromagnetic shape memory alloy applications. Keywords: Ni-Mn-Al; Heusler alloy; Mechanical alloying; Ball milling; Structural properties

Shape Memory Alloy-Based Wearables: A Review, and Conceptual Frameworks on HCI and HRI in Industry 4.0.

Ever since its discovery, the applications of Shape Memory Alloys (SMA) can be found across a range of application domains, from structural design to medical technology. This is based upon the unique and inherent characteristics such as thermal Shape Memory Effect (SME) and Superelasticity (or Pseudoelasticity). While thermal SME is used for shape morphing applications wherein temperature change can govern the shape and dimension of the SMA, Superelasticity allows the alloy to withstand a comparatively very high magnitude of loads without undergoing plastic deformation at higher temperatures. These unique properties in wearables have revolutionized the field, and from fabrics to exoskeletons, SMA has found its place in robotics and cobotics. This review article focuses on the most recent research work in the field of SMA-based smart wearables paired with robotic applications for human-robot interaction. The literature is categorized based on SMA property incorporated and on actuator or sensor-based concept. Further, use-cases or conceptual frameworks for SMA fiber in fabric for ‘Smart Jacket’ and SMA springs in the shoe soles for ‘Smart Shoes’ are proposed. The conceptual frameworks are built upon existing technologies; however, their utility in a smart factory concept is emphasized, and algorithms to achieve the same are proposed. The integration of the two concepts with the Industrial Internet of Things (IIoT) is discussed, specifically regarding minimizing hazards for the worker/user in Industry 5.0. The article aims to propel a discussion regarding the multi-faceted applications of SMAs in human-robot interaction and Industry 5.0. Furthermore, the challenges and the limitations of the smart alloy and the technological barriers restricting the growth of SMA applications in the field of smart wearables are observed and elaborated.

Effect of alloying constituents on thermal, microstructural, mechanical and shape memory properties of Cu-Al-Ag shape memory alloys

PurposeThe purpose of this study is to assess the influence of Al and Ag addition on thermal, mechanical and shape memory properties of Cu-Al-Ag alloy.Design/methodology/approachThe material is synthesized in a controlled atmosphere to minimize the reaction of alloying elements with the atmosphere. Cast samples were homogenized, then subjected to hot rolling and further betatized, followed by step quenching. Eight samples were chosen for study among which first four samples varied in Al content, and the next set of four samples varied in Ag composition.FindingsThe testing yielded a result that the increase in binary alloying element decreased transformation temperature range but increased entropy and elastic energy values. It also improved the shape memory effect and mechanical properties (UTS and hardness). An increase in ternary alloying element increased transformation temperature range, entropy and elastic energy values. The shape memory effect and mechanical properties are enhanced by the increase in ternary alloying element. The study revealed that compositional variation of Al should be limited to a range of 8 to 14 Wt.% and Ag from 2 to 8 Wt.%. Microstructural and diffraction studies identified the ß’1 martensite as a desirable phase for enhancing shape memory properties.Originality/valueNumerous studies have been made in exploring the transformation temperature and phase formation for similar Cu-Al-Ag shape memory alloys, but their influence on shape memory effect was not extensively studied. In the present work, the influence of Al and Ag content on shape memory characteristics is carried out to increase the design choice for engineering applications of shape memory alloy. These materials exhibit mechanical and shape memory properties within operating ranges similar to other copper-based shape memory alloys.

(TiB+La2O3)/Ti-V-Al lightweight high temperature shape memory composites with high strength fabricated by reaction hot pressing and hot rolling

In the present study, lightweight high-strength Ti-V-Al based high temperature shape memory composites were fabricated to broaden the application of shape memory alloys. In-situ TiB whiskers and La2O3 particles were introduced and the distribution of reinforcements was optimized by the combination of low-energy milling, hot-press sintering and subsequent hot rolling. The in-situ reinforcements formed a network structure, which evolved from an equiaxed shape to an ellipsoidal shape. Furthermore, the direction of the reinforcement was inclined to the rolling direction. In the reinforcement-lean area, the phase constitution evolved from the β parent phase to the α″ martensite phase, and the width of the α″ martensite gradually widened with increasing distance to the in-situ reinforcements. The composites maintained high martensitic transformation temperature characteristics. Excellent mechanical properties with a high tensile strength of 885 MPa and a large elongation of 13.1% are obtained in the composite with a 1.0 wt% LaB6 addition and 70% deformation ratio. Meanwhile, the composite realized 3.49% recoverable strain under 6% pre-strain conditions.

The role of NiTi shape memory alloys in quality of life improvement through medical advancements: A comprehensive review.

The significance of advanced smart materials in recent technological research and advancement is apparent from its extensive use in present day devices and instruments. Of the various smart materials in use today, the fascinating category of shape memory alloys (SMAs) is equipped with the ability to return to a previously memorized shape under certain thermomechanical or magnetic stimuli. The unique property of shape memory effect and superelasticity displayed by these materials along with good biocompatibility and corrosion resistance make them ideal for biomedical applications. The various applications of SMAs in surgical instruments, surgical implants, and assistive and rehabilitative devices have significant effect on the day to day life of people in the present age. Majority of these biomedical devices belong to the orthodontic, orthopedic, or surgical fields. Other remarkable applications of SMAs such as in the production of prostheses and orthoses designed through the biomimetic approach are also highly influential in improving the quality of life. The present paper provides an overview of the various properties of shape memory alloys and their applications in the biomedical field over the years, that have had a significant impact on the realm of medical science.

Low-energy irradiation induced giant quasilinear superelasticity over wide temperature range in NiTi shape memory alloys

Continuous strain glass transition (STGT) in shape memory alloys (SMAs) has attracted much attention and shows potential applications in biomedical, robotics, and micro-electromechanical systems due to its quasilinear superelasticity (SE). However, the reported strain glass system in NiTi alloys through doping antisite point defects can only produce local $R$-phase martensitic domains and show small recoverable strain ($\ensuremath{\sim}1%$), which limits its wide applications. Here, we propose a method to design B19\ensuremath{'} strain glass with large recoverable strain in NiTi binary alloys by introducing interstitial atoms and vacancies through low-energy irradiation by integrating molecular dynamics and phase field modeling. The interstitial atoms play the most important role to transform the normal martensitic transformation (MT) to STGT. A complete phase diagram is established to describe the relationship between MT/STGT and irradiation energy. The system after large irradiation energy $(\ensuremath{\sim}5.3\ifmmode\times\else\texttimes\fi{}{10}^{12}\phantom{\rule{0.16em}{0ex}}\mathrm{keV}/\mathrm{c}{\mathrm{m}}^{2})$ has shown obvious frequency dependence of storage modulus, continuous volume fraction change, and B19\ensuremath{'} martensitic nanodomains, which confirm the existence of B19\ensuremath{'} STGT. This B19\ensuremath{'} strain glass has shown large recoverable strain $(\ensuremath{\sim}5.8%)$ over a wide temperature range (from 100 to 300 K), which can be attributed to the continuous nucleation and growth of martensitic nanodomains in this temperature range. Our calculations theoretically proposed a method to design strain glass systems with giant quasilinear SE by interstitial defects and may stimulate the application of SMAs.

New applications for shape memory alloys in angular - contact ball bearings preloading systems

Shape Memory Alloys (SMA) have been researched extensively in the past forty years. The different available compositions of these alloys can make them suitable for certain applications with specific requirements. The increasing demand for high precision machinery and equipment brought forward the need to search for alloys that that can perform better under stress than conventional materials. This is the case of Shape Memory Alloys. As their name suggests, these alloys can regain their initial shape after being subjected to external stresses, up to a specific degree. Due to the research carried out over the past two decades on these alloys, they became better known and more accessible, being tested in order to be integrated in various applications. One such application consists of using a shape memory alloy formed into disc springs in order to optimize the preloading of angular contact ball bearings. The tests were conducted using a device especially developed for this research, with the purpose of recording the friction torque evolution and the preload induced by disc springs during the operation of the rolling bearings in order to assess the possibility of using elastic elements for active ball bearings preloading systems.

Simultaneous enhancement of mechanical and shape memory properties by heat-treatment homogenization of Ti2Ni precipitates in TiNi shape memory alloy fabricated by selective laser melting

• The simultaneous enhancement of mechanical and shape memory properties are obtained by homogenizing Ti 2 Ni precipitates in Ti 50.6 Ni 49.4 SMAs by SLM. • The Ti 50.6 Ni 49.4 SMAs with homogeneous Ti 2 Ni precipitates possesses ultimate tensile strength 880 ± 13 MPa and large fracture strain 22.4 ± 0.4%, circumventing the strength-ductility trade-off of TiNi SMAs by additive manufacturing. • The Ti 50.6 Ni 49.4 SMAs with homogeneous Ti 2 Ni precipitates also displays 5.32% recoverable strain and above 98% recovery rate, far superior to those in most of TiNi SMAs by additive manufacturing reported so far. The excellent shape memory and mechanical properties of TiNi shape memory alloys (SMAs) fabricated using selective laser melting (SLM) are highly desirable for a wide range of critical applications. In this study, we examined the simultaneous enhancement of mechanical and shape memory properties using heat-treatment homogenization of Ti 2 Ni precipitates in a Ti 50.6 Ni 49.4 SMA fabricated using SLM. Specifically, because of the complete solution treatment, nanoscale spherical Ti 2 Ni precipitates were homogeneously dispersed throughout the grain interior. Interestingly, the resultant SMA exhibited an ultrahigh tensile strength of 880 ± 13 MPa, a large elongation of 22.4 ± 0.4%, and an excellent shape memory effect, with a recovery rate of > 98% and ultrahigh recoverable strain of 5.32% after ten loading–unloading cycles. These simultaneously enhanced properties are considerably superior than those of most previously reported TiNi SMAs fabricated using additive manufacturing. Fundamentally, the enhancement in tensile strength is ascribed to precipitation strengthening and work hardening, and the large plasticity is mainly attributed to the homogeneous nanoscale globular Ti 2 Ni precipitates, which effectively impeded the rapid propagation of microcracks. Furthermore, the enhanced shape memory properties are derived from the suppression of dislocation movement and formation of retained stabilized martensite by the presence of high-density dislocations, nanoscale Ti 2 Ni precipitates, and abundant interfaces. The obtained results provide insight into the enhancement of the two types of properties in TiNi SMAs and will accelerate the wider application of SMAs.

Preface

The Fourth international conference “Shape Memory Alloys” (SMA 2021) continues the tradition of regular scientific events on shape memory alloys held in various cities of the Soviet Union: Kiev (1980, 1991), Voronezh (1982), Tomsk (1985), Novgorod (1989), Kosov (1991), St. Petersburg (1995). These days, the First conference “Shape Memory Alloys: properties, technologies, and prospects” was held in 2014 in Vitebsk (Belarus), the Second one – in 2016 in St. Petersburg, the Third one – in 2018 in Chelyabinsk. The aim of the conference is to review modern research and development directions in the field of shape memory alloys and related phenomena: from studying their structure, physical, mechanical, and functional properties to mathematical modeling of the shape memory materials’ behavior and their applications. The conference schedule comprised oral and poster presentations in the framework of three parallel sections:• Structure, martensitic transformations and shape memory effects in alloys.• The theory of martensitic transformations and shape memory effect: modeling and calculations.• Novel materials. The manufacturing technology and application of shape memory alloys. Editors of Proceedings: Sergey Prokoshkin, Natalia Resnina, Sergey Dubinskiy, Yulia Zhukova, Vadim Sheremetyev, Victor Komarov, Kristina PolyakovaList of Organizers, Program committee, Local Organizing Committee are available in this pdf.

The Analyses of the Rate of Pitting Corrosion of a NiTi Rod in a Natural Marine Environment

The analysis of the behaviour of new materials in the natural environment is important for their application and commercial use. In order to explore the application of Shape Memory Alloys in the Maritime industry, this research focuses on the corrosive behaviour of the NiTi rod that was produced by means of a continuous casting process. The experiment included three samples of NiTi rods that were exposed to the marine environment for 6, 12 and 18 months at a depth of 3 metres below the surface. The morphological and chemical changes were analysed separately during the experiment. Ultrasonic thickness equipment and the Scanning Electron Microscope (SEM) technique were used for the tests that determined the corrosion rates and detected pitting. The changes in the chemical composition of the NiTi rod were investigated by means of an Energy Dispersive X-ray (EDX) analysis, in order to define the pitting behaviour of the rod`s surfaces during its exposure to seawater. The obtained research results prove that the rate of pitting corrosion follows a progressive curve – the minimum value of corrosion rate equalled 0.04 mm/month, while the maximum value was 0.12 mm/month.

SMAワイヤ螺旋状配置によるモーフィング駆動システムの有効性と実装課題の考察

Morphing wings have various possibilities to realize drag and noise reduction and to extend flight envelope by smoothly changing wing shape during flight. This study focuses on the application of Shape Memory Alloy (SMA) wires as a lightweight actuation mechanism for morphing wings because SMA has a large recovery stress per unit mass. To achieve the required actuation stroke for the SMA wires, it was considered to design the spiral configuration of the SMA wires. This research experimentally observes the relationship between the recovery strain as the actuation performance of tube-guided wires and its geometric parameters such as spiral angle. It was found that the friction force between the SMA wire and its spirally guiding tube plays an important role on the actuator performance, and the performance gradually decreased as the length of the wires and the number of spirals increased. Furthermore, the application of the spiral configuration of SMA wire for a small aircraft was investigated. As a result, the effectiveness depends on the coefficient of the friction between the SMA wire and the spiral tube. Thus, the results obtained in this study could be used to properly design the tube-guided SMA coil-type actuators for morphing wings considering the effectiveness and challenges in its implementation.

Areas of recent developments for shape memory alloy: A review

Shape memory alloys (SMA) also known as smart materials, can return to their original shape when being heated. These materials memorize their original form and return to their original form when heated. During the past few years, it has drawn tremendous interest in a wide range of applications. It is attracting researchers to explore various unexplored horizons and implementing the material to take advantage of it, due to their unique properties of regaining their original shape. The development of 3-D printing has revolutionized the manufacturing field and the possibility of making SME with additive manufacturing has been reviewed. This review highlights the general concept of SMA, history, shape memory effect (SME), various types of SMA, recent developments in the fabrication technique of SMA, and its application have been discussed in detail. The latest application of SMA in the field of automotive, aerospace, marine, robotics, structures, and biomedical has been reviewed while discussing its challenges and advantages.

Influence of strain rate on mechanical properties of a CuAlMnTiB shape memory alloy

Some applications of shape memory alloys (SMAs) require severe deformation of the ingot cast into thin circular, flat and tubular shapes. Therefore, the knowledge of the influence of the strain rate on the mechanical properties is fundamental to determine the thermomechanical conditions that should be imposed on the SMAs during the plastic forming step of these materials. Herein, a systematic investigation of the influence of strain rate for a CuAlMnTiB SMA, on stress-induced martensite, rupture strain, ultimate strength and residual strain were evaluated. The influence of the imposed strain on the shape recovery percentage after heating the samples was also discussed. The results revealed changes in the properties with strain rate, not only in mechanical properties but also in the micromechanisms of fracture and residual strain after cyclic mechanical testing. This analysis expands the spectrum of studies on mechanical properties and superelasticity for CuAlMn system alloys, indicating the strain rate conditions in which the alloy must be submitted to preserve the characteristics required in a given practical application.

Surface Nanopatterned Shape Memory Alloy (SMA)‐Based Photosensitive Artificial Muscle

AbstractLight‐driven shape memory alloy (SMA)‐based microscale actuators show great promise for artificial muscle and biomedical applications, as they are actuated remotely and have a fast response speed. However, ultraviolet (UV) light is required for device actuation; thus, the operating environment has been limited. Here, an infrared (IR) light‐driven SMA actuator is proposed, in which the plasmonic effect is used to enhance IR light absorptance. A sub‐micrometer pattern is used to create an optical meta‐surface capable of tuning the light absorptance. Conical nanohole arrays are fabricated with a focused ion beam. The absorptance tuning effect is evaluated in terms of the optical characteristics and performance of the actuator. The nanopatterned surface increases the narrow‐band IR light absorption by up to 55%. Optics simulations are conducted to verify the experimental results. A pattern design method is proposed, based on the light wavelength of the stimulating source. Combining heterogeneous surfaces, both UV and IR light achieve decoupled microscale actuation. These actuators show a response similar to that of the iris muscle, which is responsible for the eye's pupillary reflex. It is expected that these actuators will broaden SMA applications in clinical devices and soft robotics.

Application of shape memory alloys in engineering – A review

Shape Memory Alloy is a smart alloy which retains their original shape under thermomechanical or magnetic variation. Shape Memory Alloy are widely used in different engineering field because of its superior properties and variety of application. Recent research of SMA has been applied in the field of Aerospace, Automotive, Biomedical, and Robotics. This memory effect is due to the presence of austenite and martensite crystalline structures. These alloys are bio-compatible, lightweight, and also possess a high force-to-weight ratio. Due to this SMA actuators are very much suitable for soft robotic applications. However, due to high cooling times during phase change, SMA has small bandwidth and low operating frequencies. This alloy can replace a sensor as it performs the same work done by sensors or transducer. An extensive review of history, material characterization, and opportunities of SMA in the engineering field.

Application of Shape Memory Alloys in Retrofitting of Masonry and Heritage Structures Based on Their Vulnerability Revealed in the Bam 2003 Earthquake.

For decades, one of the most critical considerations of civil engineers has been the construction of structures that can sufficiently resist earthquakes. However, in many parts of the globe, ancient and contemporary buildings were constructed without regard for engineering; thus, there is a rising necessity to adapt existing structures to avoid accidents and preserve historical artefacts. There are various techniques for retrofitting a masonry structure, including foundation isolations, the use of Fibre-Reinforced Plastics (FRPs), shotcrete, etc. One innovative technique is the use of Shape Memory Alloys (SMAs), which improve structures by exhibiting high strength, good re-centring capabilities, self-repair, etc. One recent disastrous earthquake that happened in the city of Bam, Iran, (with a large proportion of masonry buildings) in 2003, with over 45,000 casualties, is analysed to discover the primary causes of the structural failure of buildings and its ancient citadel. It is followed by introducing the basic properties of SMAs and their applications in retrofitting masonry buildings. The outcomes of preceding implementations of SMAs in retrofitting of masonry buildings are then employed to present two comprehensive schemes as well as an implementation algorithm for strengthening masonry structures using SMA-based devices.

Efficacy of prestressed SMA diagonal loops in seismic retrofitting of non-seismically detailed RC beam-column joints

In this study, a detailed experimental and numerical investigation is carried out to study the efficacy of prestressed SMA diagonal compression loops in seismic retrofitting of non-seismically detailed RC beam-column joints. Prestressed diagonal compression loops exert active confinement to the joint core which is found to perform better than the conventional passive confinement in terms of improving the shear strength, ductility, and energy dissipation capacity. In this study, active confinement of the joint core is achieved by applying in-plane diagonal compression forces using externally fastened prestressed NiTiNb shape memory alloy (SMA) diagonal loops. In the experimental part, two different techniques are investigated to prestress the SMA loops, which are: 1) rapid heat-activated prestressing technique utilizing the shape memory feature of SMAs; and 2) conventional prestressing of SMA loops by mechanical means. In the finite element analysis, a wide range of prestress values (post-tension force) is studied, keeping the basic arrangement same. The efficacy of the retrofitting technique is evaluated in terms of enhancement in strength, ductility, energy dissipation capacity, damage reduction in the specimens, and the ease of application. The results from this study suggest that depending on the applied confinement level, the retrofitting scheme can increase the ultimate strength in the range of 20–30% and the energy dissipation capacity in the range of 60–70% however, no significant enhancement in ductility of the retrofitted specimen may be achieved using this approach. The study also highlights the complexity involved in controlling the material behaviour of NiTiNb SMA wires and the risks associated with the application of SMAs in practical problems.

Актуатор с последовательным соединением стержня из сплава с памятью формы и упругого элемента смещения

One of the most promising applications of shape memory alloys (SMA) is their use for creating working bodies of power exciters (actuators). The working body of the actuator must perform certain movements due to shape memory phenomena (heating, working stroke of the actuator) and the accumulation of direct transformation deformations (cooling, idling of the actuator). It is known that the process of deformation of SMA during cooling occurs only in the presence of mechanical action, while the return to the original form during heating occurs in the absence of a corresponding mechanical action and even in the presence of a sufficiently large counteraction. To ensure the possibility of not only working, but also idling of the actuator, the working body of the SMA is connected to the elastic bias element so that both of these elements are deformed together. In this case, when the SMA element is heated, it is deformed due to the shape memory phenomenon, which leads to the deformation of the bias element associated with the working body and the appearance, both in this element and in the working body, of mechanical stresses that increase with the temperature of the SMA element. It is these stresses, which continue to act during the cooling of the working body, that ensure its deformation in the opposite direction at the stage of cooling of the working body and the corresponding direct transformation into SMA. In this paper, the behavior of an actuator consisting of a SMA rod and an elastic rod (an bias element) connected in series, the total length of which is assumed to be unchanged, is analytically investigated. The influence of the system parameters on the stresses in the SMA rod and the value of the working stroke of the actuator is investigated. The conditions for the implementation of the closed two way shape memory effect in this system are determined.

Architected material analogs for shape memory alloys

Architected material analogs for shape memory alloys

A Review on Application of Shape Memory Alloys

SMA has drawn massive interest and hobby in today’s years in a great form of an extensive sort of commercial applications, due to their precise and superior properties, this concern improvement has been bearing with the useful resource of way of improvement and carried out research studies. SMA can heal its original shape at a certain temperature even under maximum loads applied and huge inelastic deformation. In this overview, we describe the primary functions of SMAs, their constitutive models, and their features. We also explained various properties that help to build a device/system. These devices help in cueing health issues such as heart treatment emptying urine so on. SMA has important in reducing the vibration of structures by increasing damping of the materials and this has effective in energy dissipating comparing with other materials. In the aerospace industry wing aircraft, rotorcraft, spacecraft, and micro-electromechanical systems are made up of SMA. In the automobile sector, fuel injectors and thermal valves are constructed with SMA materials. Current work focuses on various applications and properties of SMA, in the field of Medical, Civil structure, Automobile, and Aerospace industry.