As an excellent giant-magnetostrictive material, Tb-Dy-Fe alloys(based on Tb0.27-0.30Dy0.73-0.70Fe1.9-2Laves compound) can be applied in many engineering fields, such as sonar transducer systems, sensors, and micro-ac...As an excellent giant-magnetostrictive material, Tb-Dy-Fe alloys(based on Tb0.27-0.30Dy0.73-0.70Fe1.9-2Laves compound) can be applied in many engineering fields, such as sonar transducer systems, sensors, and micro-actuators. However, the cost of the rare earth elements Tb and Dy is too high to be widely applied for the materials. Nowadays, there are two different ways to substitute for these alloying elements. One is to partially replace Tb or Dy by cheaper rare earth elements, such as Pr, Nd, Sm and Ho; and the other is to use non-rare earth elements, such as Co, Al, Mn, Si, Ce, B, Be and C, to substitute Fe to form single MgCu_2-type Laves phase and a certain amount of Re-rich phase, which can reduce the brittleness and improve the corrosion resistance of the alloy. This paper systemically introduces the development, the fabrication methods and the corresponding preferred growth directions of Tb-Dy-Fe alloys. In addition, the effects of alloying elements and heat treatment on magnetostrictive and mechanical properties of Tb-Dy-Fe alloys are also reviewed, respectively. Finally, some possible applications of Tb-Dy-Fe alloys are presented.展开更多
Dy-Fe alloy replace dysprosium in the NdFeB permanent material can improve the performance and productivity and cut the cost.The electrolyte is a binary system of molten DyF3-LiF.Iron is cathode and graphite is anode....Dy-Fe alloy replace dysprosium in the NdFeB permanent material can improve the performance and productivity and cut the cost.The electrolyte is a binary system of molten DyF3-LiF.Iron is cathode and graphite is anode.The raw material is Dy2O3 oxide.The content of dysprosium is (78 ～85 ) ± 1% in the Dy-Fe alloy made by electrolyzing in the industry producing.In the course of electrolyzing the efficiency of current, the alloy formation and the productivity of rare earths by studying the formation of electrolyte, the electrolyzing temperature, the standards and the current density of cathode, the anode shape etc were studied.The conclusion is that we can produce Dy-Fe alloy (the content of dysprosium is (78 ～ 85 ) ± 1% ) in this condition, the efficiency of current is greater than 68 %, and the productivity of rare earth is greater than 92%.The content of oxygen, calcium, wolfram is smaller than the content by reducing.展开更多
The electromagnetic levitation melting of the rare earth giant magnetostrictive materials Tb 0.27 Dy 0.73 Fe 1.90 alloys is realized. The compound is difficult to realize levitation melting at terrestrial environment ...The electromagnetic levitation melting of the rare earth giant magnetostrictive materials Tb 0.27 Dy 0.73 Fe 1.90 alloys is realized. The compound is difficult to realize levitation melting at terrestrial environment because of its high density and low electric conductivity. The microstructure of the sample near peritectic composition obtained by this process contains REFe 2 matrix phase, a large amount of rod like REFe 3 phase embedded in the matrix phase, rare earth rich phase enriching around the REFe 3 phase and a small amount of rare earth rich phase in the REFe 2 matrix phase far from the REFe 3 phase, which is significantly different from that of the sample obtained by general melting casting process with the same composition,which contains almost complete REFe 2 phase and a small amount of RE rich phase in the REFe 2 matrix phase. The formation of the microstructure can be attributed to the coupled growth of the peritectic phase—REFe 2 and the primary phase—REFe 3 , and the subsequent eutectic reaction under this experimental condition.展开更多
Magnetostrictive actuators normally use twin-crystal magnetostrietive materials as driving unit. Because the crystal and twin- crystal plane hinder the movement of the domain wall, its displacement output of low magne...Magnetostrictive actuators normally use twin-crystal magnetostrietive materials as driving unit. Because the crystal and twin- crystal plane hinder the movement of the domain wall, its displacement output of low magnetic strength is rather small. Using Tb-Dy-Fe single crystal technique can effectively solve the problems brought by pollution and twin crystals, and produce high-quality Tb-Dy-Fe single crystal materials. The paper will introduce the technique of using these materials to produce magnetostrictive actuators that possess high sensitivity and resolution and use pulse feeding.展开更多
The electrochemical behavior of Dy 3+ on Fe electrode in molten NaCl KCl DyCl 3 has been studied by means of cyclic voltammetry, electrode potential time curve after potentiostatic electrolysis, potential st...The electrochemical behavior of Dy 3+ on Fe electrode in molten NaCl KCl DyCl 3 has been studied by means of cyclic voltammetry, electrode potential time curve after potentiostatic electrolysis, potential step method, and X ray diffraction Experimental results indicate that the Dy Fe alloy forms at first and then the intermetallic compounds of Dy Fe containing more Dy form in sequence The metallic Dy deposits at last The number of intermetallic compounds for Dy Fe system has been determined at 1073 K The standard free energy of formation for (1/2)Dy 2Fe 17 , (1/6)Dy 6Fe 23 , DyFe 3, and DyFe 2 determined are -92 64, 83 10, -76 99, and -59 05 kJ/mol at 1073 K The relationship between diffusion coefficient and temperature of Dy atom in Dy Fe intermetallic compound can be expressed as ln D =-72 9×10 3/ RT -14 7, and the diffusion activation energy is 72 9 kJ/mol The Dy Fe alloy was prepared by consumable cathode in molten chlorides The Dy Fe alloy containing Dy near 90%(wt) was obtained The composition of alloy was DyFe 3 and Dy展开更多
Rare-earth intermetallic compounds formed in many R-Fe-Mn（R=rare-earth element） systems exhibit excellent properties. In order to understand the existence and stability of the compounds in the system and further sea...Rare-earth intermetallic compounds formed in many R-Fe-Mn（R=rare-earth element） systems exhibit excellent properties. In order to understand the existence and stability of the compounds in the system and further search for the potential application of R-Fe-Mn alloys in various aspects, it is necessary to investigate the phase relations of the Dy-Fe-Mn ternary system. A total of 96 samples of the Dy-Fe-Mn alloys were prepared by arc-melting and examined by metallographic analysis, X-ray diffraction（XRD）, scanning electron microscopy（SEM） and energy dispersive spectroscopy（EDS） techniques. The phase relationship of the Dy-Fe-Mn system at 773 K was determined. It was found that the isothermal section was characterized by intermediate solid solutions based on the substitutions of Fe/Mn atoms and the large extensions of the binaries into the ternary domains. The solid solubilities of the third element in the binary compounds and the phase boundaries were also determined by XRD technique using the phase disappearing method combined with the lattice parameter method and SEM/EDS technique. Two pairs of corresponding binary compounds in the Dy-Fe and Dy-Mn systems（DyFe2 and DyMn2, Dy6Fe23 and Dy6Mn23） formed a continuous series of solid solution at 773 K, respectively.展开更多
文摘As an excellent giant-magnetostrictive material, Tb-Dy-Fe alloys(based on Tb0.27-0.30Dy0.73-0.70Fe1.9-2Laves compound) can be applied in many engineering fields, such as sonar transducer systems, sensors, and micro-actuators. However, the cost of the rare earth elements Tb and Dy is too high to be widely applied for the materials. Nowadays, there are two different ways to substitute for these alloying elements. One is to partially replace Tb or Dy by cheaper rare earth elements, such as Pr, Nd, Sm and Ho; and the other is to use non-rare earth elements, such as Co, Al, Mn, Si, Ce, B, Be and C, to substitute Fe to form single MgCu_2-type Laves phase and a certain amount of Re-rich phase, which can reduce the brittleness and improve the corrosion resistance of the alloy. This paper systemically introduces the development, the fabrication methods and the corresponding preferred growth directions of Tb-Dy-Fe alloys. In addition, the effects of alloying elements and heat treatment on magnetostrictive and mechanical properties of Tb-Dy-Fe alloys are also reviewed, respectively. Finally, some possible applications of Tb-Dy-Fe alloys are presented.
文摘Dy-Fe alloy replace dysprosium in the NdFeB permanent material can improve the performance and productivity and cut the cost.The electrolyte is a binary system of molten DyF3-LiF.Iron is cathode and graphite is anode.The raw material is Dy2O3 oxide.The content of dysprosium is (78 ～85 ) ± 1% in the Dy-Fe alloy made by electrolyzing in the industry producing.In the course of electrolyzing the efficiency of current, the alloy formation and the productivity of rare earths by studying the formation of electrolyte, the electrolyzing temperature, the standards and the current density of cathode, the anode shape etc were studied.The conclusion is that we can produce Dy-Fe alloy (the content of dysprosium is (78 ～ 85 ) ± 1% ) in this condition, the efficiency of current is greater than 68 %, and the productivity of rare earth is greater than 92%.The content of oxygen, calcium, wolfram is smaller than the content by reducing.
文摘The electromagnetic levitation melting of the rare earth giant magnetostrictive materials Tb 0.27 Dy 0.73 Fe 1.90 alloys is realized. The compound is difficult to realize levitation melting at terrestrial environment because of its high density and low electric conductivity. The microstructure of the sample near peritectic composition obtained by this process contains REFe 2 matrix phase, a large amount of rod like REFe 3 phase embedded in the matrix phase, rare earth rich phase enriching around the REFe 3 phase and a small amount of rare earth rich phase in the REFe 2 matrix phase far from the REFe 3 phase, which is significantly different from that of the sample obtained by general melting casting process with the same composition,which contains almost complete REFe 2 phase and a small amount of RE rich phase in the REFe 2 matrix phase. The formation of the microstructure can be attributed to the coupled growth of the peritectic phase—REFe 2 and the primary phase—REFe 3 , and the subsequent eutectic reaction under this experimental condition.
基金Funded by State "863" Plan Project(863-715-003-0040-2)
文摘Magnetostrictive actuators normally use twin-crystal magnetostrietive materials as driving unit. Because the crystal and twin- crystal plane hinder the movement of the domain wall, its displacement output of low magnetic strength is rather small. Using Tb-Dy-Fe single crystal technique can effectively solve the problems brought by pollution and twin crystals, and produce high-quality Tb-Dy-Fe single crystal materials. The paper will introduce the technique of using these materials to produce magnetostrictive actuators that possess high sensitivity and resolution and use pulse feeding.
文摘The electrochemical behavior of Dy 3+ on Fe electrode in molten NaCl KCl DyCl 3 has been studied by means of cyclic voltammetry, electrode potential time curve after potentiostatic electrolysis, potential step method, and X ray diffraction Experimental results indicate that the Dy Fe alloy forms at first and then the intermetallic compounds of Dy Fe containing more Dy form in sequence The metallic Dy deposits at last The number of intermetallic compounds for Dy Fe system has been determined at 1073 K The standard free energy of formation for (1/2)Dy 2Fe 17 , (1/6)Dy 6Fe 23 , DyFe 3, and DyFe 2 determined are -92 64, 83 10, -76 99, and -59 05 kJ/mol at 1073 K The relationship between diffusion coefficient and temperature of Dy atom in Dy Fe intermetallic compound can be expressed as ln D =-72 9×10 3/ RT -14 7, and the diffusion activation energy is 72 9 kJ/mol The Dy Fe alloy was prepared by consumable cathode in molten chlorides The Dy Fe alloy containing Dy near 90%(wt) was obtained The composition of alloy was DyFe 3 and Dy
文摘采用酚醛树脂粘结Tb0.27Dy0.73Fe1.95合金颗粒,在磁场取向作用下压制成形制备复合材料,研究粉末粒度、成形压力对其密度、磁致伸缩性能和动态磁导率的影响。结果表明,400 MPa成形压力下,250~420μm粉末制备的样品密度可达6.6 g/cm^3,在400 k A/m磁场下的磁致伸缩系数为731×10^-6,比粉末粒度为38~58μm的样品高110×10^-6。样品在5~50 kHz的交流磁场中磁导率变化幅度低于2%,具有很好的频率稳定性;交流磁场叠加偏置磁场的条件下,样品在1 k Hz交流磁场下无偏置磁场的磁导率为4.4,偏置磁场为1 528.3 A/m时增加到10.2,增加幅度大于131%。
基金Project supported by National Natural Science Foundation of China(50861005,51261002)the Natural Science Foundation of Guangxi(2011GXNSFD018005)
文摘Rare-earth intermetallic compounds formed in many R-Fe-Mn（R=rare-earth element） systems exhibit excellent properties. In order to understand the existence and stability of the compounds in the system and further search for the potential application of R-Fe-Mn alloys in various aspects, it is necessary to investigate the phase relations of the Dy-Fe-Mn ternary system. A total of 96 samples of the Dy-Fe-Mn alloys were prepared by arc-melting and examined by metallographic analysis, X-ray diffraction（XRD）, scanning electron microscopy（SEM） and energy dispersive spectroscopy（EDS） techniques. The phase relationship of the Dy-Fe-Mn system at 773 K was determined. It was found that the isothermal section was characterized by intermediate solid solutions based on the substitutions of Fe/Mn atoms and the large extensions of the binaries into the ternary domains. The solid solubilities of the third element in the binary compounds and the phase boundaries were also determined by XRD technique using the phase disappearing method combined with the lattice parameter method and SEM/EDS technique. Two pairs of corresponding binary compounds in the Dy-Fe and Dy-Mn systems（DyFe2 and DyMn2, Dy6Fe23 and Dy6Mn23） formed a continuous series of solid solution at 773 K, respectively.
