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1
Content available remote Structure and physical properties of Fe59Mn27Ni7Cr3Si4 shape memory alloy
EN
In this work the authors present the properties of the Fe59Mn27Ni7Cr3Si4 (at. %) shape memory alloy. Two different phases were discovered during the XRD analysis and Fe-Mn phase was identified. The hardness of the investigated material in the as-cast state was 194 HV. The nano hardness was 511 HV and Young modulus was determined as 159 GPa. AFM and LFM tests allowed to observe linear arrangement of one phase formed as multiple irregular separations. Shape memory effect was not observed in the temperature range 22 – 600oC.
EN
Ni55.8Ti shape memory alloys (SMAs) find applications in different fields of medical and engineering. In every field, surface integrity greatly affects the functional performance of shape memory alloy parts. In the present work, wire spark erosion machining of Ni55.8Ti shape memory alloys has been conducted and surface integrity parameters of the machined specimens have been evaluated. Experiments are designed using Taguchi L16 robust design of experiment technique. Effect of important process parameters, i.e. voltage, pulse-on time and pulse-off time on maximum surface roughness has been studied. Deterioration in surface integrity at various combinations of pulse-on and pulse-of time which produced high discharge energy has been observed. Scanned electron microscopic investigation, energy dispersive spectroscopy and XRD analyses, roughness measurement, and micro-hardness testing results are presented, analyzed and discussed. Optimization of process parameters resulted in surface integrity enhancement with low roughness (Rt – 7.78 mm and Ra – 1.45 mm) and very thin recast layer (4–6 mm) along with minimum subsurface defects.
EN
Advanced subjects in mechanical properties of shape memory alloys and polymers are discussed. In the subloop loading under a stress-controlled condition of the shape memory alloy, the transformation-induced stress relaxation appears due to variation in temperature. The enhancement of corrosion and corrosion fatigue life of the shape memory alloy is discussed. The development of a functionally-graded shape memory alloy and polymer is expected to obtain better performance. Three-way motion appears in the shape memory composite with the shape memory alloy and polymer.
EN
Cu-Al-based high temperature shape memory alloys are preferred commonly due to their cheap costs and shape memory properties. In recent years, studies have been conducted on developing and producing a new type of Cu-Al based shape memory alloy. In this study, the CuAl-Cr alloy system, which has never been produced before, is investigated. After production, the SEMEDX measurements were made in order to determine the phases in the Cu84–x Al12Crx+4(x = 0, 4, 6) (weight %) alloy system; and precipitate phases together with martensite phases were detected in the alloys. The confirmations of these phases were made via x-ray measurements. The same phases were observed by XRD diffractogram of the alloys as well. The values of transformation temperature of alloys were determined with Differential Scanning Calorimetry (DSC) at 20°C/min heating rate. According to the DSC results, the transformation temperature of the alloys varies between 320°C and 350°C. This reveals that the alloys show high temperature shape memory characteristics.
EN
The aim of the present paper is to examine both the fatigue behaviour and the phase transition mechanisms of an equiatomic pseudo-elastic NiTi Shape Memory Alloy through cyclic tests (up to 100 loading cycles). More precisely, miniaturised dog-bone specimens are tested by using a customised testing machine and the contents of both austenite and martensite phase are experimentally measured by means of X-Ray diffraction (XRD) analyses. On the basis of such experimental results in terms of martensite content, an analytical model is here formulated to correlate the stress-strain relationship to the phase transition mechanisms. Finally, a validation of the present model by means of experimental data pertaining the stress-strain relationship is performed.
6
Content available Different Types of Ventilation Systems of Munitions
EN
In the article it is presented the guideline and requirements for construction and technology designing of munition, that allows mitigation and decreasing after effects of stimuli impacting the Insensitive Munition (IM), used in military equipment, i.e. in case of pressure and temperature increase during fire, fast and slow heating, sympathetic detonation, perforation of the munition by a projectile, a fragment or a shaped charge jet. The construction of the IM munition is specified with the use of barriers, ventilation/deaeration of the munition case and double-purpose technology. The features of the active and passive/inert ventilation systems of the IM munition are presented, examples of absorbing energy materials and structure of covers/barriers of a „sandwich” type. Depending on the IM classes of threats and different representative standards and one metric of munition response and technology maturity, there are different consequences of detonation, explosion, deflagration/propulsion, burn, not sustained reaction, etc. observed. Some examples are presented with the use of the shaped-memory alloys or polymers in the Insensitive Munition.
PL
W artykule zaprezentowano wytyczne i wymagania dotyczące projektowania konstrukcji i technologii amunicji, które pozwalają złagodzić i zmniejszyć efekt bodźca uderzenia w amunicję małowrażliwą (IM) stosowaną w sprzęcie wojskowym, tj. w przypadku wzrostu ciśnienia i temperatury w czasie palenia, szybkiego i powolnego ogrzewania, przenoszenia detonacji, przebicia amunicji przez pocisk, odłamek lub strumień pocisku kumulacyjnego. W konstrukcji amunicji małowrażliwej (IM) pokazano użycie barier, wentylacji/odpowietrzenia obudowy amunicji i technologii o podwójnym zastosowaniu. Zaprezentowano cechy aktywnych i pasywnych systemów wentylacji bezwładnościowej amunicji małowrażliwej, przykłady materiałów absorbujących energię i strukturę pokryć/barier typu „kanapka”. W zależności od klasy zagrożeń amunicji małowrażliwej (IM) i różnych odpowiednich standardów dla amunicji o długości jednego metra, zaawansowania technologii, obserwuje się różne rezultaty detonacji, wybuchu, deflagracji/napędzania, palenia, niepodtrzymywania reakcji itp. Zaprezentowano przykłady użycia stopów lub polimerów z pamięcią kształtu w amunicji małowrażliwej.
EN
The effect of hydrostatic pressure and different heating/cooling rates on physical properties and microstructure of NiTi shape memory alloy has been investigated. The transformation temperatures and physical properties of the alloy have changed with applied pressure. It has been clearly seen from Differential Scanning Calorimetry (DSC) that with the increase of applied pressure, while As and Af, and Mf transformation temperatures decrease, Ms value increase. Moreover, based on the increase of the pressure amount applied on the sample, there was an average increase of 48% for Gibbs free energy and 18% for elastic strain energy. Entropy of the alloys decreases depending on the increase in the amount of applied pressure for all heating rates. Depending on the amount of applied pressure on the sample, an interior strain of 0.177% at most was observed. With the increase of applied pressure on the sample, it was determined that activation energy increased. Additionally, the Scanning Electron Microscopy (SEM) images of the samples show that the grain sizes of the unpressured sample and the samples on which pressure is applied are between 40 and 120 μm, which was determined by Image Analysis Method.
EN
In order to develop the reciprocating rotary driving actuator with a simple mechanism using shape memory alloy (SMA) tapes, the graphical method to design the actuator was proposed based on the torsional deformation properties of SMA tapes. The torsional deformation properties of the SME tape showing the shape memory effect (SME) and the SE tape showing superelasticity (SE) were obtained. The bias-type reciprocating rotary actuator was composed of the pretwisted SME tape and the flat SE tape in series. The design chart expressed by the relationship between torque and twisting angle of the SME tape and the SE tape was proposed. The rotational angle and torque, which vary depending on temperature, can be estimated based on the design chart. The rotational angle is controlled by adjusting the mounting angle of the SME tape and the heating temperature. The automatically opening and closing blind driven by sunlight was demonstrated. The blind was controlled by using the reciprocating rotary element composed of the SME tape and the SE tape. The behavior of the blind can be achieved based on the proposed design method of the reciprocating rotary driving element.
EN
Purpose: The effect of shape memory and super-elastic property are two exclusive features in shape memory alloys. To exploit the properties of shape memory effect, alloy needs to be heated, but super-elastic property in these alloys will be proposed automatically in case suitable conditions. Design/methodology/approach: In this study, with simulating short-square reinforced concrete column experimental model in software ANSYS and in multi-level and increasing process, longitudinal armatures with shape memory alloy material will replace steel armatures with super-elastic behavior will be investigated with making shape memory alloy kind as variable (copper and nickel-based alloys), the opportunity of super-elastic property emergence in these alloys and with playing the role of longitudinal armature in reinforced concrete column. Findings: It can generally be said that memory alloy will achieve to goal that its created stresses will be located among stress of beginning direct phase and stress of finishing direct phase and whatever these stresses are closer to finishing direct phase, alloy will have more efficiency to propose its super-elastic property. Research limitations/implications: In case of using shape memory alloys as longitudinal armatures in reinforced concrete structures considering them buried in concrete, exploitation of shape memory property will have its particular problems that these problems won’t happen about the super-elastic property. Considering the high rate of strain capacity (3 to 8%) in memory alloys with super-elastic behaviour and the limitation of this capacity in concrete, conditions are necessary to be prepared in a way that memory alloy has the opportunity to propose super-elastic property. Originality/value: Except shape memory alloy that has proposing super-elastic behaviour in concrete structures and is investigated in this study, other factors such as the rate of resistance characteristic of pressure of concrete and mechanical characteristics of steel armatures are effective in this case as well that can be good subjects for investigation.
EN
The paper presents different types of insensitive munition used in military equipment, especially in western countries. Tests of this munition, their parameters, e.g. fast and slow heating, bullet, fragment and shaped charge jet impact and sympathetic reaction are described. The characteristics of shape-memory materials like alloys and polymers are presented. Behaviour of shape-memory alloy is explained by example of TiNi al-loys during mechanical or thermal loading, and martensitic transformation into austen-ite during unloading. Material parameters of the TiNi alloys, their testing and mathematical equations are shown. Venting systems used in the explosive reactive armour cassettes are presented. Different examples of materials, including shapememory materials in munition, are demonstrated.
11
Content available remote Contactless displacement converter with switching measurement range
EN
The main goal of this article is to show the method for automatic change of measuring range of designed displacement-to-voltage converter. The designed displacement-to-voltage converter is used in fully automated test bench for investigation of SMA material properties. The entire designed system makes possible measurements of electro-thermo-mechanical characteristics. The main control components were implemented in LabVIEW program.
PL
W artykule przedstawiono rozszerzenie możliwości pomiarowych przetwornika „odkształcenie-napięcie” działającego w złożonym systemie pomiarowym służącym do pomiaru właściwości cięgien wykonanych ze stopu SMA. Liniowa charakterystyka przetwarzania umożliwiła takie oprogramowanie komputera sterującego systemem pomiarowym, oprogramowanego w LabVIEW, aby w przypadku przekroczenia zakresu pomiarowego nastąpiło automatyczne przełączenie zakresu. Zmiana zakresu pomiarowego związana jest z przesunięciem charakterystyki przetwarzania poprzez zmianę wyrazu wolnego liniowej funkcji przetwarzania. W artykule zaprezentowano koncepcję automatycznego przełączania zakresu, sprawdzono realizowalność zadania dla danego przetwornika, przeanalizowano błędy pomiarowe wynikające ze zmiany skali, przedstawiono algorytm działania oraz realizację w programie LabVIEW.
13
Content available remote The applicability of shape memory alloys in structures
EN
The structural application of shape memory materials is relatively new. It is possible that these materials provide the unusual property of creating stress in steel bars in a thermomechanical way. Depending on the alloy composition and production treatment, the characteristic transformation temperatures as well as the mechanical properties of the material vary and this may limit its technical effectiveness. The present work is focused on the material parameters from the point of view of practice.
PL
Zastosowania konstrukcyjne materiałów z pamięcią kształtu są stosunkowo nowe. Materiały te mogą prezentować nietypową właściwość wywoływania naprężeń w prętach stalowych wskutek reakcji termomechanicznej. Charakterystyczne temperatury przemian fazowych, a także właściwości mechaniczne stopu zależą od jego składu oraz procesu produkcji, co może mieć wpływ na techniczną efektywność materiału. Niniejsza praca dotyczy cech materiałów z pamięcią kształtu z punktu widzenia praktycznych zastosowań.
EN
A shape-memory alloy (SMA) is expected to be applied as intelligent or smart material since it shows the functional characteristics of the shape memory effect and superelasticity. Most SMA elements, with these characteristics, perform cyclic motions. In these cases, the fatigue property of SMA is one of the most important issues in view of evaluating functional characteristics of SMA elements. The fatigue properties are complex since they depend on stress, strain, temperature and their hysteresis. If an SMA is implanted with high-energy ions, the thermomechanical properties of the material may change, resulting in long fatigue life. In the present study, the nitrogen ion implantation was applied to modify the surface of a TiNi SMA tape and the influence of implantation treatment on the bending fatigue properties was investigated.
EN
The present study deals with crush tests of concrete cylinders confined by shape memory alloy (SMA) wires. Two cases were considered. First, an active confinement was achieved by wrapping a wire previously prestrained in martensitic state and then subjected to the memory effect. Second, a passive confinement was obtained by using the same SMA, but in austenite state. For comparison purpose, an unconfined cylinder was also tested. The influence of the unwrapped zones of the confined cylinders was also investigated, leading to the use of a specially designed device to avoid premature failure in these zones. The comparison between active and passive confinements was investigated. The test results show that stiffness, strength and ductility are significantly improved in the case of the active confinement.
16
EN
Purpose: of this paper is to predict the effect of cold deformation to transformation temperatures of Ni–Ti SMA and clarify the relation between cold forming ratio and the parameters of thermo mechanical process. Design/methodology/approach: 25% and 50% cold formed Ni–Ti wire specimens are investigated for defining the relation between the ratio and the parameters of thermo mechanical processes of without annealing and with annealing at 450°C for 30 minutes and 600°C for 30 minutes. Moreover, Differential Scanning Calorimeter (DSC) measurements are applied to the specimens for obtaining the transformation temperatures. Findings: According to DSC measurements, start and finish temperatures of transformation of austenite, martensite and rhombohedral phases are calculated. Hence, their changes are related to deformation and annealing, so it can be implied that cold deformation process leads to increases in the temperature ranges, slow occurrences of transformation and also the shape memory property lowers. Research limitations/implications: It is observed that some specimens exhibit rhombohedral phase transformation and this affects the martensite phase transformation temperatures and results. Thus, annealing time can be increased to determine both positive and negative effect to transformation properties for further research. Moreover, the grainsize and form may also be effective, so this case should be studied. Practical implications: can be stated as suitable transformation temperatures must be paid attention to desired service temperatures of products those are made of Ni–Ti SMAs, otherwise they may exhibit unexpected shape change due to the affected transformation temperature. Originality/value: is that Ni–Ti SMAs may be exposed to cold deformation when they are manufactured for being given any product shape, so with this research it can be determined that if their transformation temperatures change or not. Besides, it can be implied that they change and so this study presents the changes, the intervals of start and finish temperatures relevant to the cold forming ratio.
17
Content available remote Structure of TCP layer deposited on surface of NiTi shape memory alloy
EN
The number of NiTi shape memory alloy application in medicine grows from year to year. However, relatively high contents of nickel cause concern for their migration to a human body. Especially, it appears, when they are going to be applied for long-term implants. In order to increase biocompatibility and corrosion resistance, surface of NiTi alloy is modified with deposition of protective layer. The layer can play also additional function for example: osteointegration. However, to stiff and/or thick protective layer as well as high temperature of their deposition can limit or completely block shape memory effect. In presented work, the ß-TCP was electrophoretically deposited on surface of the NiTi alloy. The protective layer was deposited with use of voltage from range of 20÷45 V and deposition time varied from 15 s to 30 s. Homogeneous layer formed from ß-TCP phase was produced with voltage of 30 V and time 30 s. Applied deposition procedure allowed avoid of the B2 parent phase decomposition to equilibrium phases.
PL
Liczba praktycznych zastosowań stopów NiTi wykazujących efekt pamięci kształtu w medycynie wzrasta z roku na rok. Jednakże zastosowanie tych stopów na długoterminowe implanty jest ograniczone obawami przed uwalnianiem się jonów niklu do organizmu człowieka. W celu zwiększenia biokompatybilności oraz odpomości korozyjnej powierzchnię stopów NiTi modyfikuje się przez nanoszenie warstw ochronnych, które mogą również pełnić dodatkowe funkcje, np. polepszać osteointegrację. Jednakże zbyt sztywne i/lub zbyt grube powłoki ochronne oraz zbyt wysoka temperatura ich nanoszenia mogą ograniczyć lub nawet całkowicie zablokować efekt pamięci kształtu. W pracy zastosowano trójfosforan wapnia nanoszony elektroforetycznie na powierzchnię stopu NiTi. Warstwę ochronną nanoszono w temperaturze pokojowej, stosując napięcie z zakresu 20÷45 V oraz czas nanoszenia od 15 do 30 s. Homogeniczną warstwę złożoną z cząstek ß-TCP na powierzchni NiTi uzyskano przy napięciu 30 V oraz czasie 30 s. Warunki elektroforetycznego nanoszenia warstwy nie spowodowały rozpadu fazy macierzystej stopu NiTi na fazy równowagowe.
EN
This paper describes some studies on the development of shape memory alloy (SMA) coresheath friction yarns. SMA wires for actuating purposes were utilised as a conductive element in the core-sheath friction yarn. A DREF 3000 friction spinning machine was used to produce the yarns. The conductive yarn was spun with the SMA actuator wire at the core and 100% cotton fibers in the second layer as the sheath producing a yarn called SMA core-sheath friction yarn (SMA CSFY). During spinning, the core-sheath ratio and spinning drum speeds were varied. The main purposes of the study were to evaluate the SMA CSFY single yarn tensile strength and its actuating performance against changes in the spinningprocess parameters. The results showed that SMA CSFY with the highest spinning drumspeed and 60% core gave the highest tensile strength and fastest actuation performance.
PL
Badania dotyczyły opracowania przędz rdzeniowych z udziałem składnika posiadającego pamięć kształtu. Druty z pamięcią kształtu zostały zastosowane jako elementy elektrycznie przewodzące. Do produkcji tych przędz zastosowano przędzarkę DREF 3000. Przędze przewodzące były produkowane z rdzeniem z drutów o pamięci kształtu oraz otoczką z włókien bawełnianych (100%). Przędzenie przeprowadzano przy zmianie prędkości bębna przędącego. Głównym celem badań była ocena właściwości wytrzymałościowych otrzymanej przędzy oraz wpływ parametrów przędzenia na pamięć kształtu przędzy. Wyniki badań wskazują, że przędze otrzymane przy najwyższych prędkościach bębna przędącego i udziale rdzenia 60% posiadają najlepsze właściwości wytrzymałościowe i korzystne reakcje na zmianę kształtu.
EN
If a shape memory alloy (SMA) is subjected to the subloop loading under the stress-controlled condition, creep and creep recovery can appear based on the martensitic transformation. In the design of SMA elements, these deformation properties are important since the deflection of SMA elements can change under constant load. The conditions for the progress of the martensitic transformation are discussed based on the kinetics of the martensitic transformation for the SMA. The creep deformation properties are investigated experimentally for TiNi SMA. The creep strain rate increases in proportion to the martensitic transformation strain; the creep recovery strain rate increases in proportion to the reverse transformation strain.
EN
In order to develop a brain spatula made of a shape memory alloy (SMA), this paper discusses the bending characteristics of a new brain spatula precision-cast in a TiNi SMA. The results obtained can be summed up as follows. (1) With respect to an SMA-brain spatula having the same length and width as the existing type made of copper, if the new cast SMA spatula is 1.2 times as great in thickness as the existing copper spatula, or if a conventionally rolled SMA spatula is 1.3 times as great, the SMA instrument will offer the same bending rigidity and withstand almost as great a bending force as the copper one. (2) Expressing the bending fatigue life of the copper or SMA in the region of low-cycle fatigue as a power function of the maximum bending strain, the fatigue life of the SMA is longer than that of the copper. For both the cast and the rolled SMAs, the fatigue life is longer under pulsating-plane bending than under alternating plane bending.
PL
W pracy opisano problem projektowania szpatułki używanej w chirurgii mózgu, wykonanej ze stopu z pamięcią kształtu (SMA). Przedyskutowano charakterystyki zginania nowej szpatułki wykonanej z precyzyjnie odlewanego stopu TiNi. Wyniki badań podsumowano w następujący sposób: (1) w porównaniu do konwencjonalnych, miedzianych szpatułek o tej samej długości i szerokości, jeśli odlewana szpatułka SMA jest 1.2 raza grubsza od miedzianej, lub 1.3 raza, gdy wykonana została przez walcowanie, instrument ten będzie posiadał taką samą sztywność giętną i wytrzyma niemalże to samo obciążenie zginające, jak w przypadku narzędzia miedzianego; (2) wyrażając wytrzymałość zmęczeniową szpatułki miedzianej w rejonie niskocyklicznych obciążeń jako funkcję potęgową maksymalnego odkształcenia przy zginaniu, stwierdzono, że szpatułki SMA wykazują dłuższą żywotność od konwencjonalnych. W obydwu przypadkach – odlewanej i walcowanej szpatułki SMA – wytrzymałość zmęczeniowa jest większa dla płaskiego jednostronnego zginania od wytrzymałości przy zginaniu przemiennym.
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