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EN
Paper shows study on the magnetoelectric composite material placed in an external magnetic field with changing magnetic field vecotr. An experimental setup for investigation of magnetoelectric properties of magnetostrictive-piezoelectric material was prepared. The hybrid structure is made of magnetostrictive composite (based on Terfenol-D) and piezoelectric material. Experimental results shown the response of prepared hybrid material to the rate of changes of direction of magnetic field vector. Investigation were mainly focused on possibility of generating of electric power from prepared material. It was found that the prepared hybrid material exhibits magnetoelectric effect in the case of work when direction of magnetic field vector was changing. This effect might be use in Energy Harvesting applications.
EN
The aim of this work was to observe the changes in the magnetomechanical properties of composite materials with different Tb0.3Dy0.7Fe1.9 (Terfenol-D) powder particle-size distributions and varying volume fractions in the polyurethane matrix. The results show a direct relationship between the properties and the particle size of the Tb0.3Dy0.7Fe1.9 powder: the increases in the particle-size distribution of the Tb0.3Dy0.7Fe1.9 powder in the matrix amplify the magnetostrictive responses and the compressive modulus values. Moreover, it was found that the key role in efficiency of the transformation of magnetic energy into mechanical plays the initial compressing pre-stress.
PL
Celem pracy jest określenie zmian własności magnetomechanicznych materiałów kompozytowych o zróżnicowanej wielkości cząstek Tb0.3Dy0.7Fe1.9 oraz zmiennym udziale wzmocnienia w osnowie poliuretanowej. Otrzymane wyniki wskazują na bezpośrednią zależność pomiędzy własnościami a rozmiarem cząstek Tb0.3Dy0.7Fe1.9: zwiększenie ich wielkości powoduje wzrost wartości magnetostrykcji oraz modułu ściskania. Stwierdzono ponadto, że kluczową rolę w efektywnej transformacji energii magnetycznej w mechaniczną odgrywa naprężenie wstępne.
3
Content available remote Characterization of composite materials with giant magnetostriction
EN
Purpose: This paper concerns manufacturing and researching a new group of the magnetostrictive composite materials, consisting Tb0.3Dy0.7Fe1.9 particles in different polymer matrix. Design/methodology/approach: The following investigation studies have been carried out: the structures of the Tb0.3Dy0.7Fe1.9 powders, the topography of composite materials fractures with the use of electron scanning microscopy; chemical composition of the Tb0.3Dy0.7Fe1.9 powders using the EDS method; phase composition of the Tb0.3Dy0.7Fe1.9 powders and composite materials using X-ray diffraction; as well as properties of the composite materials with polyurethane matrix reinforced with Tb0.3Dy0.7Fe1.9 particles including: density, thermal conductivity (in magnetic field also), electrical and magnetic properties, as well as magnetostriction in magnetic field intensity up to 800 kA/m using a three terminal capacitance technique. Findings: Based on the examination carried out it was found that the highest magnetostriction equals to 805∙10-6 (with magnetic field intensity of 766 kA/m) characterizes a composite material with polyurethane matrix, reinforced with Tb0.3Dy0.7Fe1.9 powder of 20% volume fraction and particles size in the range of 38-106 μm. Simultaneously, the materials is characterized with coercion intensity Hc=5.39 kA/m, remanence Br=0.013 T and magnetic permeability μr=1.13. Moreover, it was found that the maximum magnetostriction value for this material assumes values approximate to the magnetostriction of monolithic Tb0.3Dy0.7Fe1.9 alloy. Additionally, it was confirmed that the correlation exists between the diversification of the volume fraction of Tb0.3Dy0.7Fe1.9 powder in the matrix, its particle distribution and the maximum magnetostriction and magnetic properties of the developed composite materials. The key factor determining the energy transfer efficiency between Tb0.3Dy0.7Fe1.9 and matrix is – in addition to the size and volume fraction of the magnetostrictive particles in the matrix – the method of combining those two phases. Originality/value: The paper presents the research involving the composite material with giant magnetostriction.
EN
In the paper, a construction and principle of working of a giant magnetostrictive actuator have been presented. The effects of varied operating conditions such as magnetic bias and mechanical prestress on the magnetostriction characteristics is discussed. The magnetic circuit of the actuator is analyzed using finite element method. The selected results of calculations are presented.
PL
W pracy omówiono budowę i zasadę działania magnetostrykcyjnego aktuatora z rdzeniem wykonanym z Terfenolu-D. Analizowano wpływ namagnesowania i naprężenia wstępnego rdzenia z Terfenolu-D na pracę magnetostrykcyjnego aktuatora. Do wyznaczania rozkładu pola wykorzystano metodę elementów skończonych. Przedstawiono wybrane wyniki obliczeń symulacyjnych.
EN
Purpose: The aim of this work is to obtain functional composite materials and to observe changes of magnetic properties of samples with different particle size distributions of magnetostrictive Terfenol-D (Tb0.3Dy0.7Fe1.9) powder. The influence of the concentration and particles size of the Tb0.3Dy0.7Fe1.9 on magnetic properties were investigated as function of applied magnetic field intensity, temperature and frequency. Design/methodology/approach: The investigated samples were obtained by casting of the composite materials with the polyurethane matrix reinforced with Tb0.3Dy0.7Fe1.9 particles. Magnetizations versus applied field curves were registered using the Oxford Instruments Ltd. vibrating sample magnetometer (VSM). Volume magnetic susceptibility was determined as temperature function on the Cahn RG automatic electrobalance (Ventron Instrumens, USA). Testing of the magnetic permeability in function of frequency was made using the Maxwell-Wien bridge system and the electrical properties were made by the resistivity measurements. Findings: Analysis establishes a direct connection between physical properties and structural characteristics of the Tb0.3Dy0.7Fe1.9 powder size: the increases of particle size distribution of Tb0.3Dy0.7Fe1.9 powder in composite materials amplify the magnetic responses and - at the same time - causing growth of resistivity values also. Moreover, in the investigated frequency range, no effect was observed of frequency on the susceptibility value for the particular material, which suggests possibility of using these materials in the high-frequency magnetic fields. Practical implications: The polyurethane matrix in investigated composite materials causes growth of resistivity, limiting these way losses for eddy currents at the high operating frequency of the transducers. Originality/value: The obtained results show the possibility of manufacturing the magnetostrictive composite materials based on the Tb0.3Dy0.7Fe1.9 particles, with desired physical properties (including electrical one) in cost effective way in comparison to conventional giant magnetostrictive materials (GMM).
EN
Purpose: The purpose of this study was to determine the thermal and electrical conductivity of composite materials with the polyurethane matrix reinforced with Tb0.3Dy0.7Fe1.9 particles with different particle size distributions and varying volume concentration. Design/methodology/approach: The investigated samples were obtained by casting of the composite materials with the polyurethane matrix reinforced with Tb0.3Dy0.7Fe1.9 particles. There were determined the samples density, electrical properties (by a resistivity measurements), thermal conductivity (by Physical Property Measurement System with thermal transport option), as well as the metallographic investigations (by stereo microscope). Findings: It was found from obtained results that the resistivity value for composite materials filled with larger particle size Tb0.3Dy0.7Fe1.9 was lower than the smaller particles size filled composites. Moreover, it may be noticed that thermal conductivity has an approximate value for different Tb0.3Dy0.7Fe1.9 particle size and the same its volume fraction in matrix. Simultaneously it was also observed that the thermal conductivity of the composite materials did not depend on the temperature within the tested range from 293 to 333 K. Research limitations/implications: Contributes to research on structure and physical properties of magnetostrictive composite materials with the polyurethane matrix reinforced with Tb0.3Dy0.7Fe1.9 particles. Practical implications: The polyurethane matrix in investigated composite materials causes growth of resistivity, limiting this way losses for eddy currents at the high operating frequency of the transducers. Originality/value: The obtained results show the possibility of manufacturing the magnetostrictive composite materials based on the Tb0.3Dy0.7Fe1.9 particles, with desired physical properties (including thermal and electrical one) in cost effective way in comparison to conventional giant magnetostrictive materials (GMM).
PL
Zastosowano wysokotemperaturową spektroskopie mösbauerowska do zbadania reakcji (oddziaływań) międzyfazowych w mieszaninie związku międzymetalicznego Dy0,73Tb0,27Fe2 (Terfenol-D) z Pb(Zr0,5Ti0,5)O3 (PZT) w warunkach beztlenowych (wysoka próżnia). Przeprowadzono syntezę związku międzymetalicznego Dy0,73Tb0,27Fe2 drogą topienia w elektrycznym piecu łukowym w próżni. Na podstawie badań rentgenowskich określono jego strukturę krystaliczną i położenia atomów w komórce elementarnej. Wykonano obliczenia ab initio struktury elektronowej i na tej podstawie potwierdzono metaliczno–kowalencyjny charakter wiązania chemicznego oraz wyznaczono stałe sprężystości i moduły Younga, sztywności i ściśliwości Dy0,73Tb0,27Fe2. Przeprowadzono badania oddziaływań pomiędzy związkiem Dy0,73Tb0,27Fe2 i PZT, wykorzystując efekt Mössbauera mieszaniny. Stwierdzono rozkład Terfenolu-D na ziemię rzadką i żelazo zaczynający się już w 400 K. Powstające żelazo występuje jako Fe3+ w koordynacji tetra- i oktaedrycznej, co jest charakterystyczne dla struktury perowskitu jaką posiada PZT. Wskazuje to na jego migrację w głąb tej fazy. Jedynie niewielka część żelaza tworzy Fe2O3 (hematyt), nie zaobserwowano natomiast występowania Fe2+. Badania pokazały, że zmiany form żelaza zaobserwowane na podstawie badań mössbauerowskich są czułym wskaźnikiem oddziaływań pomiędzy Terfenolem-D i PZT.
EN
High temperature Mössbauer spectroscopy was used to study reactions between phases in Dy0.73Tb0.27Fe2 and PZT mixtures in high vacuum. Dy0.73Tb0.27Fe2 was synthesized using an electric arc melting technique. Crystal structure and atom positions of the compound were determined by XRD measurements. The ab inito computations of electronic bands structure of the investigated material were done and covalent – metallic character of the bonds was confi rmed and elastic constants together with Young’s, shear and bulk moduli were determined. The Dy0.73Tb0.27Fe2 and PZT mixtures were prepared. High temperature Mössbauer effect measurement of the Dy0.73Tb0.27Fe2 /PZT mixtures demonstrate the effect of decomposition the intermetalic compound into rare earth and iron. This decomposition starts already at 400 K. The iron liberated during this decomposition is incorporated in the PZT structure as Fe3+ in tetra and octahedral coordination. Small quantity of iron exists as Fe2O3. The Fe2+ iron was not observed.
EN
In the last 30 years, discovery of Terfenol-D has led to development of magnetostrictive actuators. In the paper the mathematical model of magnetostrictive actuator is presented. The model is suitable to describe relation between the input magnetic field, the magnetization in the magnetostrictive rod, the output displacement, magnetostriction and the strain of magnetostriction actuator. Frequency characteristics of giant magnetostrictive actuator are obtained. The selected results of calculations are compared and discussed.
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