Shape Memory Effect In Alloys Research Articles

Investigating the Shape Memory Effect and Corrosion Resistance of the Fe-(17-2x) Mn-6Si-xNi-yCr-0.3C Alloys (x = 0, 1, 2, 3, 4; y = 0, 1, 3, 5)

In this study, low Mn content Fe-Mn-Si-based shape memory alloys [Fe-(17-2x) Mn-6Si-xNi-yCr-0.3C (x = 0, 1, 2, 3, 4; y = 0, 1, 3, 5)] were prepared via vacuum arc remelting. The alloys were hot-rolled and solid-solution-treated at 1150 °C for 1 h followed by aging at elevated temperatures. The effects of Cr and Ni addition on the shape memory performance and corrosion resistance of the alloys in 3.5 wt% NaCl solutions were investigated using bending test and potentiodynamic polarization, respectively. It was revealed that the recoverable strain of the alloys remains larger than 2% when 1Ni is replaced with 2Mn and Cr is added. However, it becomes less than 2% in 11Mn and 9Mn alloys because of the easy formation of the α’ martensite. The shape memory effect of alloys is highly improved due to the precipitation of fine carbides in the grains by the addition of Cr and after aging treatment at elevated temperatures (≧700 °C). The highest shape recovery ratios of 88.3% for 17Mn0Ni3Cr, 94.0% for 15Mn1Ni3Cr, 94.4% for 13Mn2Ni5Cr, 88.1% for 11Mn3Ni5Cr, and 86.8% for 9Mn4Ni7Cr, respectively, were achieved after 800 °C aging treatment. The strip-like second phase (carbides) forms at the grain boundaries in the Cr-free alloys after 600 °C aging treatment. There are lots of fine carbides (M23C6 and M7C3) precipitated in the interior of the grains at the aging treatments ≧ 700 °C. However, M7C3 is eliminated at 900 °C aging treatment. The corrosion resistance results showed that the corrosion resistance of the alloys is improved by adding Cr. The maximum corrosion potentials (−0.474 V) have been observed for 13Mn2Ni5Cr, and similar mechanisms have been analyzed in all series of alloys.

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 influence of thermo-mechanical treatment on phase transformation and shape memory effect of CuAl9Fe4Ni2 alloy

Shape memory alloys can return to their original shape by reversible martensitic transformation. The shape memory effect of these alloys has been considered to relate to phase transformation, especially martensite transformation. In the copper-aluminum alloys containing Fe and Ni additives, the relationship between the martensitic transformation and shape memory effect occurs by applying a thermo-mechanical deformation and heat treatment process. This paper presents the phase transformation of the CuAl9Fe4Ni2 alloy that suffered from the deformation and heat treatment process. The samples were heated above 1173°K for homogenization. Then, they were rolled with an appropriate degree of strain to prepare the good conditions for the next steps. They were heated again to 1173°K, then quenched in water to 373°K, and then cooling down in cold water to form martensites with fine grain sizes. Next, the samples underwent cold deformation to create a fine grain in the structure and a favorable distribution for the shape memory process. Finally, the samples were shaped and heated at 843°K to decompose the martensite phase and return to their original shape. The phase transformation and the structure of martensite were determined by modern analytical techniques. The results show that the shape memory level was up to 80%.

A Study of the Possible Use of Materials With Shape Memory Effect in Shipbuilding

The article presents a study of the possible use of materials with Shape Memory Effect (SME) in shipbuilding, which have two special abilities of transformation and changing shape with changing of temperature or deformation. Among the most well-known SME materials, our study focuses on Ni-Ti and Cu- based alloys. An example of the existing fabrication presents casting of Ni-Ti in the form of a disk, and a new approach – continuous casting of Ni-Ti and CuAlNi alloys in the form of rods. In the article some results are shown of characterisation of microstructure and the basic properties. This was done in accordance with the fact that such scientific approach could define the starting point for further identification of the functional characteristics of these alloys by knowing the their chemical content and microstructure. Numerous studies are being carried out today in order to find the optimal functional characteristics of SME alloys. All of this is aimed at optimising the fabrication of these alloys, with the achievement of suitable properties for application in shipbuilding.

OPPORTUNITIES FOR USING INNOVATIVE SHAPE MEMORY EFFECT MATERIALS IN OIL INDUSTRY

The discovery of the shape memory effect (SME) in the field of metal physics was the beginning of a large stage of research on new materials with specific properties Titanium nickelide (NiTi) is known as an alloy that exhibits a large-size shape memory effect and at the same time has good strength, ductility and corrosion resistance. The practical application of these materials in various devices began only in the seventies of the last century. This paper is devoted to the study of the possibility of using SME materials for solving particular problems in the oil and gas industry, including the use of the SME materials as connecting elements for pipelines and reinforcing bars for foundations of large-sized structures used in difficult engineering and geological conditions. These proposals will ensure a significant margin of safety for the oil and gas facilities under consideration and their safe operation. The analysis of domestic and foreign works on the use of SME materials in various areas of the oil and gas industry is fulfilled. Information on the basic physical, mechanical, and functional properties of SME alloys is given. The theoretical substantiation of the effective use of SME materials as sleeve couplings for field pipelines as an alternative to flammable welding at fire hazard enterprises, as well as the use of prestressed reinforcement SME alloys for the construction of plate foundations for large hydrocarbon reservoirs instead of traditional reinforcement, has been carried out. Calculation of stresses and strains in the ANSYS software environment has shown the high potential effectiveness of applying the SME technology to implement the described tasks.

Intelligent Materials Used in Hydraulic, Fuel, and Rudder Control Systems of Aircrafts

The device is really , only if it is capable to respond to changing external conditions. The devices, which feel the external environment and can change their characteristics, have many advantages compared to the conventional devices: they are more efficient, wear out more slowly, and have lower operating costs. The scope of smart products is truly infinite. Alloys with memory effect also apply to intellectual content. Natural piezoelectric crystals such as silicon dioxide (intellectual material) have been known for over a hundred years. They have greater stiffness and can be used at high operating frequencies. Due to the direct piezoelectric effect, they have been successfully used as a strain gage. Later came artificial ceramic piezoelectric materials; they are used as mechanical transducers. Thus, an inverse piezoelectric effect is usually used. It consists in the change of dimensions when an electric field is applied. Control of intellectual structure can be provided by heat fluxes, electromagnetic, hydraulic or piezoelectric forces and through application of electro-rheological, and magneto-rheological fluids. The article examines the intellectual materials and technologies that are already in place or will find its application in aviation hydraulic and fuel systems and control systems of rudders (CSR) of aircrafts in the near future. The paper considers in detail the shape memory effect alloys (SMEA) as intelligent materials. Actuators made from SMEA have a number of advantages: high working power; large recoverable deformation; different types of strain (tensile, compressive, bending and torsional); most specific value of the work per unit mass. All the SMEA advantages may be well used for the so-called thermo-mechanical connections (TMС) of pipelines where SMEA drawbacks in this application, practically, do not affect the quality of TMC. In aircraft engineering the TMC were first used in hydraulic systems of the aircraft TU204. The paper also considers piezoelectric transducers, which are based on the reverse piezoelectric effect that converts electrical power into mechanical strain or displacement. The use of piezoelectric effect in hydraulic systems, rudder control systems, fuel systems of aircrafts will allow significant improving the static and dynamic characteristics of amplifiers (precision, speed, dynamic sensitivity, bandwidth, weight, etc.)

The structure–phase transformations and mechanical properties of the shape memory effect alloys based on the system Cu–Al–Ni

The effect of the alloying with 9 to 14 wt % aluminum and high-temperature thermo-mechanical treatment on the structure–phase transformations in ternary Cu-Al-Ni shape memory effect (SME) alloys has been studied using methods of optical and electron microscopy, electron and X-ray diffraction analysis. The obtained results have demonstrated the possibility of the dendrite substructure elimination and prevention of an embrittlement-providing decomposition in cast alloys upon certain thermo-mechanical external action via employment of the processes of controlled recrystallization in an austenite state and subsequent quenching. The authors have established specific features of the improvement of the mechanical properties, grain structure of β austenite, and microstructure of the β’1 and the γ’1 martensite in dependence of the chemical composition of alloys and their thermo-mechanical treatment.

Features of Stress Changes in the Alloy Ti<sub>50</sub>Ni<sub>48,7</sub>Mo<sub>0,3</sub>V<sub>1</sub> under Loading in a Wide Temperature Range

The results of the study on properties of shape memory effect alloys, obtained on the basis of the experimentally determined temperature dependency of the shear martensitic stress in the alloyTi50Ni48.7Mo0.3V1, are described. It has been established that the total strain of the sample and the yield point reach a maximum value (ε = 25.5 %, σВ= 1280 МPа) at a test temperature of 300 K. It has been methodically shown how using this experiment in NiTi-based alloys it is possible to estimate temperature ranges of shape memory effect occurrence and to determine parameters of mechanical properties.

Research on Shape Memory Effect and Corrosion Resistance of the As-Cast Fe-Mn-Si Based Alloy

Shape memory effect and corrosion resistance of the as-cast Fe-Mn-Si based alloy were studied in this paper. The results showed that the shape memory effect of alloy would decline with the specimen size increasing. Due to the ε martensites distributed in a single direction mostly and uniformly were not prone to the phenomenon of cross-crossing at the small size interface. The corrosion resistance of the as-cast decreased as the concentration of medium increasing. Because of the Cl-, which was easily absorbed by the substrate in the HCl solution, can penetrate the surface of the substrate film and generate the soluble compound, which leads the corrosion resistance performance poorer than that in NaOH solution. Under high temperature and pressure, the average corrosion rate of the Fe-Mn-Si-based shape memory alloy was significantly lower than that of the 304 stainless steel, and its corrosion rate changed little. Because the amount of harmful impurity elements and the carbon content is low in the shape memory alloy matrix, and the film formed on the surface of the alloy is more stable, denser so as to an unobvious pitting behavior.

Phase Transformations and Shape Memory Effect in Alloys of Zr-Ni-Co System

Intermetallic compounds of ZrNi-ZrCo cross-section undergo martensitic phase transformation, which is accompanied by the imperfect shape memory effect at elevated temperatures. Martensitic transformation is also taking place in one of the constituents for the in-situ composites of ZrCo-Zr2Co-Zr2Ni-ZrNi region. High temperature shape memory behavior of Zr-Ni-Co composite material shows improvement in shape recovery comparing to quasibinary intermetallic compounds of ZrNi-ZrCo cross-section.

Effect of the megaplastic torsion deformation on the heat capacity of the Ni2MnGa alloy

The heat capacity of the ferromagnetic shape memory effect alloy Ni2MnGa in submicrocrystalline and amorphous-nanocrystalline states has been measured in the temperature range 2 K ≤ T ≤ 310 K. Changes in the electron, magnetic, and lattice contributions to C P (T) as a result of megaplastic torsion deformation of samples under high pressure have been discussed.

Simultaneous improvement of ductility and shape memory effect of two-phase Ni53Mn22Co6Ga19 high-temperature shape memory alloy with the addition of Ta

In this study, small Ta was added into two-phase Ni53Mn22Co6Ga19 high-temperature shape memory alloy to refine grain for further improving the ductility and shape memory effect of the alloy. It is found that small Ta addition results in the refinement of grain size. This change simultaneously improve the tensile ductility and shape memory effect of the alloy, being up to 11% and 3.3% at Ta=0.2at.%, respectively. With further increasing Ta addition to 0.4at.%, the ordered γ′ phase is present, and it tends to wrap γ phase and segregates martensite and γ phase, which lead to a decrease in the ductility of the alloy at Ta=0.4at.%. The obtained results may provide useful information on improving the ductility and shape memory effect for some other type of two-phase shape memory alloys.

Actuators based on composite material with shape-memory effect

A new scheme of composite functional material based on an alloy exhibiting a shape-memory effect (SME) is proposed. The scheme provides for a giant reversible bending deformation with the use of only “one-way”-SME alloy. An experiment was performed with the use of actuator models manufactured by gluing together the rapidly quenched ribbons and electroplating the pseudoplastically predeformed ribbons of the alloy with nickel. It is shown that the theoretical estimates of the bending moment developed by the actuator and of the reversible deformations of the actuator are in good agreement with the results of the model experiments. The prospects for the use of the new scheme in micro- and nanomechanics are considered. Actuators with record small overall dimensions have been manufactured by the focused ion-beam technique.

Influence of process factors on shape memory effect of CuZnAl alloys

Thermal cycle training of CuZnAl shape memory alloys with different transformation temperatures was carried out. The influence of different pre-strains, heat treatments and media on the shape memory effect(SME) of CuZnAl alloys with different transformation temperatures was studied by means of scanning electron microscopy(SEM) and X-ray diffractometry(XRD). Experimental results show that despite respective variation in heat treatment, medium and cycling number, the recovery rate always decreases as pre-strain increases. The decline is obvious when pre-strain is less than 2.6% but not so sharp when pre-strain exceeds 2.6%. Larger pre-strain results in more than one slip system and causes intercutting of the martensite strips among martensitic variants, then leads to the decline of SME. The SME of alloys with transformation temperatures below 347 K is larger than that of alloys beyond 361 K by 20%–40%. The recovery rate of two-step aged alloy is higher than that of step-quenched alloy by 20%–25%. During thermal cycling, the recovery rate in oil is better than that in water.

Effects of carbon addition and aging on the shape memory effect of Fe–Mn–Si–Cr–Ni alloys

The effects of carbon content and aging treatment on the microstructures and shape recovery ratio of Fe–Mn–Si–Cr–Ni alloys were studied. It was found that the carbon content possessed significant effects on the shape recovery ratio of Fe–Mn–Si–Cr–Ni alloys. The shape memory effect of alloys containing different carbon amount could be improved through aging.

Fabrication of titaniumnickel shape memory effect alloys by pulse current sintering

Fabrication of titaniumnickel shape memory effect alloys by pulse current sintering

Asymmetric Behavior of Elastic Scattering Appearing Prior to the Transformation in Au-47.5at%Cd

The shape memory effect of alloys are caused by martensitic transformation. AuCd alloy is one of the typical alloys which shows martensitic transformation. AuCd alloy has CsCl type structure as a parent phase and two distinct martensite called γ 2 ' around composition of Au-47.5at%Cd and ζ 2 ' around composition of Au-50at%Cd. Mechanism of the martensitic transformation from microscopic point of view has not been completed yet. Crystal structure of γ 2 ' phase was obtained with alternative motion of (110) plane of parent phase. Inelastic neutron scattering experiments showed softening behavior at the Brillouin zone boundary in addition to ζ≃1/3 of [ζζ0]TA 2 phonon branch. Single crystal of Au-47.5at%Cd were prepared and small fragments of the sample were electro-polished for X-ray diffraction experiments. Intensity measurements with four circle diffractometer (Rigaku AFC-5R) were performed around 1/3 and 1/2 of [110] * at several temperatures above the transformation temperature (Ms) to observe the precursor phenomenon of the martensitic transformation. Extra reflection at 1/2, which corresponds to γ 2 ' martensite reflection after the transformation, was not observed. Although the 1/3 of [110]* reflections were not expected from structural study of γ 2 ' martensite, 1/3 reflection was observed prior to the transformation temperature (Ms). They appeared asymmetrically around the Bragg reflection of the parent phase.

The Industrial Applications of Shape Memory Alloys in North America

Literature in the recent past on shape memory effect alloys dwelt principally on the physical metallurgy, crystallography and kinetics of the shape memory phenomenon. By contrast, we now have books and conference proceedings devoted to the engineering aspects of SMAs, their technology and application. The dominant role SMAs now play in the field of medical and orthodontic devices is well documented and will be reviewed by others in this conference. In this paper we will discuss the commercial applications for shape memory alloy devices in the North American market; applications which are in many cases also produced in European countries and Japan. The early success of shape memory alloy couplings for joining tubing and pipe in the late 1960's was not followed by other large volume applications until the advent of shape memory eyeglass frames, brassiere underwires and cellular phone antennas. Many other applications have now evolved into mature markets and these will be reviewed. In addition to the many commercial applications cited, there are a number of other fields in which shape memory alloys are destined to play a major role; these include smart materials and adaptive structures, MEMS devices, infrastructure systems and electrical power generation and distribution. These applications are being developed with private and government funding and will also be briefly discussed.

Influence of deformation on the force characteristics of shape memory effects in alloys based on titanium nickelide

Studies of the influence of plastic deformation and the straining temperature on the temperature dependence of the stresses developed in titanium nickelide shape memory alloys are described.

Crystallography and microstructure of TaRu

The solid-state phase transformations and crystallography of equiatomic TaRu were examined by conventional and in-situ high-temperature transmission electron microscopy, with complementary experiments using X-ray diffraction and dilatometry. This alloy undergoes two displacive phase transformations on cooling from the high-temperature B2-ordered cubic phase. The high-temperature cubic-to-tetragonal transformation produces a highly twinned microstructure similar to that observed in many shape memory effect alloys. The phase produced by the low-temperature transformation was shown by detailed microdiffraction to have a monoclinic symmetry rather than the orthorhombic symmetry which had been previously reported. The structure of this monoclinic lattice indicates the possibility of an ω-like transformation in this alloy.