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Resonance and antiresonance characteristics of μr33, d33, and d33/x33 with Hbias = 80 kA/m for the 1–3 type Tb0.22Dy0.48Pr0.3(Fe0.9B0.1)1.93 composite
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The texture-oriented TbxDy0.7−xPr0.3(Fe0.9B0.1)1.93/epoxy particulate composites are fabricated with a magnetic field of 640 kA/m. The <100>-oriented 1–3 type (x ≤ 0.16) and <111>-oriented composites (x ≥ 0.22) are obtained. The composite exhibits a negative ΔE effect of elastic modulus (E3) with trivial eddy-current losses at frequency up to 50 kH...
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Magnetostrictive Tb x Ho 0.8−x Pr 0.2 Fe 1.8 Mn 0.1 (0 ⩽ x ⩽ 0.20) alloys are prepared by arc-melting and subsequent annealing. The dopant of Pr/Mn introduced into RFe 2 compounds effectively stabilizes the forming of single C15 Laves phase at ambient pressure. The easy magnetization direction (EMD) varies when Tb content increases, which is accomp...
Citations
... The main characteristics of GMPCs of several Tb-Dy-Fe systems reported in the literature are summarized in Table 1. [88] Recently, GMPCs with a layered structure were prepared by dynamic orientation in an oscillating magnetic field [89]. Jiang et al. [87] further obtained a Tb-Dy-Fe/epoxy particle composite with a high alloy particle volume fraction (57%) and high saturation magnetostriction (1500 ppm) by using a two-step dynamic orientation method, as shown in Figure 22b, and the energy density shown in Figure 22d was markedly improved. ...
As giant magnetostrictive materials with low magnetocrystalline anisotropy, Tb-Dy-Fe alloys are widely used in transducers, actuators and sensors due to the effective conversion between magnetic energy and mechanical energy (or acoustic energy). However, the intrinsic brittleness of intermetallic compounds leads to their poor machinability and makes them prone to fracture, which limits their practical applications. Recently, the addition of a fourth element to Tb-Dy-Fe alloys, such as Ho, Pr, Co, Nb, Cu and Ti, has been studied to improve their magnetostrictive and mechanical properties. This review starts with a brief introduction to the characteristics of Tb-Dy-Fe alloys and then focuses on the research progress in recent years. First, studies on the crystal growth mechanism in directional solidification, process improvement by introducing a strong magnetic field and the effects of substitute elements are described. Then, meaningful progress in mechanical properties, composite materials, the structural origin of magnetostriction based on ferromagnetic MPB theory and sensor applications are summarized. Furthermore, sintered composite materials based on the reconstruction of the grain boundary phase also provide new ideas for the development of magnetostrictive materials with excellent comprehensive properties, including high magnetostriction, high mechanical properties, high corrosion resistance and high resistivity. Finally, future prospects are presented. This review will be helpful for the design of novel magnetostrictive Tb-Dy-Fe alloys, the improvement of magnetostrictive and mechanical properties and the understanding of magnetostriction mechanisms.
... However, some intrinsic properties of bulk alloy, including of brittleness, eddy-current losses, are seriously limited application. For this reason, epoxy-bonded composites are considered as one of the most promising candidates, because they are composed of alloys with high anisotropic magnetostriction and epoxy matrix with flexibility [5][6][7][8]. ...
The magnetostrictive materials are widely applied as modern smart materials converting electrical to mechanical energy. Here, the pseudobinary Sm0.88Nd0.12Fex compounds, free of both (expensive) heavy rare earths and B/Co stabilizer, have been prepared with mechanical alloying and subsequent solid-state sintering process. An amorphous phase can be formed by high-energy ball milling, followed by the formation of single-phase Sm0.88Nd0.12Fe1.80 alloy at an annealing temperature of 690 °C. A high anisotropic magnetostriction λa as large as 1280 ppm for the as-sintered alloy is obtained at an external field of 12 kOe. The oriented pseudo 1-3 type particulate composite is fabricated by embedding and aligning the as-sintered alloy particles in an epoxy matrix under an oriented magnetic field. The composite with a volume faction of 30% shows large magnetostriction (λa ~895 ppm at 12 kOe). In particular, λa and the longitudinal magnetostriction λ|| at a low field (3 kOe) reaches a value as high as 630 and 450 ppm, respectively, 78% and 84% larger than that of its as-sintered polycrystalline alloy although Vp is only 30%. Ultimately, it is anticipated that this work will open a new design paradigm to develop Sm-based materials with negative-magnetostriction performance.
... In Cheng-Chao Hu huchengchao@lcu.edu.cn 1 the following decades, much work has focused on the exploration of anisotropic compensation systems, such as Tb x Dy 1−x Fe 2 , Tb x Ho 1−x Fe 2 and Tb x Dy y Ho 1−x−y Fe 2 [2][3][4][5]. Subsequently, single crystals or textured pseudobinary RFe 2 -type alloys [6] were also developed for the purpose of further improving the magnetostrictive properties at low fields. However, the raw materials of these giant magnetostrictive materials in the previous work are mostly expensive heavy rare earth Tb, Dy or Ho, which limits their wide application to a certain extent. ...
Based on the light-rare-earth anisotropic compensation system, bulk nanocrystalline Pr0.5Nd0.5(Fe0.75Co0.1Cu0.01Nb0.04 Si0.05B0.05)1.93 magnetostrictive alloys were synthesized by annealing its melt-spinning ribbons under different ultrahigh pressures. It was demonstrated that high-pressure annealing could effectively synthesize the wanted magnetostrictive phase and control the grain growth of Pr0.5Nd0.5(Fe0.75Co0.1Cu0.01Nb0.04Si0.05B0.05)1.93 bulk nanocrystals. The average grain size decreased with annealing pressure increasing from 3 to 8 GPa, accompanied by a decrease in coercivity. The volume fraction of the cubic Laves phase, as well as grain size, synergistically affected the magnetoelastic response of the investigated bulk nanocrystalline magnetostrictive alloys. This work gives us an insight into the microstructure controlling of the bulk nanocrystalline magnetostrictive materials and provides a way to select suitable bulk nanocrystals to meet the different magnetostrictive applications.
Wearable and flexible magnetostrictive materials are required for the realization of devices related to the Internet of Things. Soft magnetostrictive materials are also expected to be used as tactile devices in telemedicine applications. This study reports on the successful fabrication of a material made up of Fe49Co49V2 alloy particles dispersed in a polyurethane (PU) matrix (PU–FeCoV); this material was used to make soft magnetic composite sheets with a positive magnetostriction effect. It was found that several PU–FeCoV soft composite sheets also showed a negative magnetostriction on one side of the composite sheets. This study revealed that the large pores induce this bending phenomenon in the PU–FeCoV soft composite sheet. The magnetic flux density of the PU–FeCoV soft composite sheets was found to vary with repeated loading. Hence, we believe that PU–FeCoV soft composite sheets may have potential applications as flexible sensing and vibration energy harvesting devices as well as in haptics devices.
Carbon fibre reinforced polymers composites possess properties that outstrip their component parts, and are seeing increased adoption in sectors such as the aerospace industry. Due to their complex failure mechanisms, it is necessary to have structural health monitoring (SHM) in place. Previous work has shown the efficacy of magnetostrictive materials as damage detection actuators; issues such as their spatial sensitivity require improvement to progress their applicability in SHM. Another requirement is to demonstrate ease-of-fabrication in conjunction to damage detectability, and also to maintain a good weight-to-cost trade-off. In this paper we demonstrate a step-by-step approach to the fabrication and optimisation of an impregnated magnetostrictive epoxy matrix that aims to satisfy these requirements.
