Fe_(83)Ga_(17)R_(0.6)(R=Ce,Tb,Dy)合金的微结构与磁致伸缩性能

为改善多晶Fe-Ga合金的磁致伸缩性能,在Fe-Ga合金中掺杂稀土Ce、Tb和Dy元素。研究了Fe_(83)Ga_(17)和Fe_(83)Ga_(17)R_(0.6)(R=Ce,Tb,Dy)合金的相结构和磁致伸缩性能。结果表明,Fe_(83)Ga_(17)合金由单一bcc结构Fe(Ga)固溶体相组成,而掺杂稀土后的Fe_(83)Ga_(17)R_(0.6)合金中除保持bcc结构的Fe(Ga)固溶体相外,还出现了R_2Fe_(17)第二相。掺杂稀土后的Fe_(83)Ga_(17)R_(0.6)合金磁致伸缩系数明显大于Fe_(83)Ga_(17)合金。掺杂不同种类的稀土元素对Fe-Ga合金磁致伸缩性能改善的程度不同。在外磁场为557 k A/m时,Fe_(83)Ga_(17)R_(0.6)合金的磁致伸缩系数(206×10~(-6))明显大于Fe_(83)Ga_(17)Tb_(0.6)(165×10~(-6))和FFe_(83)Ga_(17)Dy_(0.6)(161×10~(-6))合金的磁致伸缩系数。     

Fe83Ga17Dyx合金组织结构及磁致伸缩性能

研究了Fe83Ga17Dyx(x=0,0.2,0.4,0.6)系列合金的晶体结构、显微组织、磁致伸缩性能。结果表明,稀土Dy添加到Fe83Ga17合金中对合金的晶体结构影响很小,对显微组织影响显著。Fe83Ga17合金中添加稀土Dy后,性能最好的Fe83Ga17Dy0.2合金在5000 Oe外加磁场下,磁致伸缩系数达到300×10-6。     

稀土Ce添加对Fe83Ga17合金微结构和磁致伸缩性能的影响

为了改善Fe-Ga合金的磁致伸缩性能,采用真空非自耗电弧炉制备了Fe₈₃Ga₁₇Ce_x（x=0.0,0.2,0.4,0.6,0.8,1.0）合金,用X射线衍射仪（XRD）和扫描电镜及能谱仪（SEM/EDS）分析了合金的微结构,用电阻应变法测量了合金的磁致伸缩性能.结果表明:Fe₈₃Ga₁₇合金由单一的bcc结构A2相组成.而添加稀土Ce后,除x=0.2合金外,Fe₈₃Ga₁₇Ce_x合金主要由bcc结构的A2相和CeFe₂第二相组成.此外,Fe₈₃Ga₁₇合金的微观组织是晶粒粗大的等轴晶,而Fe₈₃Ga₁₇Ce_0.8合金的微观组织是晶粒细小的柱状晶.与Fe₈₃Ga₁₇对照合金相比,除x=0.2合金的磁致伸缩系数略小于对照合金外,其他添加稀土Ce后的合金样品磁致伸缩系数均明显增加.添加稀土Ce后,Fe₈₃Ga₁₇Ce_x合金的磁致伸缩系数随稀土Ce含量的增加呈现出先增加后减小的变化趋势,x=0.8合金的磁致伸缩系数最大,在557 kA/m外加磁场下,磁致伸缩系数达到356×10^-6.     

Galfenol合金的显微组织和磁致伸缩性能

采用非自耗真空电弧熔炼方式制备了不同Ga含量条件下的Fe100-xGax(X-16、19、21、27)合金铸锭,系统研究了不同成分合金铸锭的显微组织结构和磁致伸缩性能.结果发现,铸态Fe-Ga合金室温基本结构为无序的bcc结构,随着Ga原子含量的增加,立方晶格的晶格常数逐渐增加.富Ga相的数量和分布直接影响着铸态合金的磁致伸缩性能,Fe81 Ga19合金的饱和磁致伸缩最大,达到93×10-6,Fe19Ga21合金由于在26.64°附近存在(111)面有序DO3相的析出,进一步抑制了磁致伸缩性能的提高,其饱和磁致伸缩最小只有20×10-6.铸态多晶Fe84Ga16合金沿<110>方向具有一定的择优取向,因偏离<100>易磁化方向,因此其磁致伸缩系数较低. 构和磁致伸缩性能.结果发现,铸态Fe-Ga合金室温基本结构为无序的bcc结构,随着Ga原子含量的增加,立方晶格的晶格常数逐渐增加.富Ga相的数量和分布直接影响着铸态合金的磁致伸缩性能,Fe81 Ga19合金的饱和磁致伸缩最大,迭到93×10-6,Fe19Ga21合金由于在26.64°附近存在(111)面有序DO3相的析出,进一步抑制了磁致伸缩性能的提高,其饱和 致伸缩最小只有20×10-6.铸态多晶Fe84Ga16合金沿<110>方     

取向Galfenol合金的结构与磁致伸缩应变

采用非自耗真空电弧熔炼方式制备了不同Ga含量的Fe100-XGaX(X=17、19)合金铸锭,利用定向凝固的方法试验研究了取向多晶Fe-Ga合金的结构与磁致伸缩应变。研究发现,采用定向凝固工艺制备的Fe83Ga17合金试样沿轴向呈现出明显的{110}织构特征。在低场下不同成分两种试样的磁致伸缩随磁场的增加迅速增大,在磁场强度大约为40 kA/m时Fe83Ga17合金的磁致伸缩λ达到饱和,为55×10-6。Ga含量为19%的定向凝固试样沿轴向取向性有所降低,晶粒中存在很多的亚晶界。富Ga相的析出和亚晶界的出现不利于磁致伸缩性能的提高。     

Fe-Ga合金薄带的显微组织及磁致伸缩性能

采用熔体快淬的方法制备了成分分别为Fe100-x Gax (x=17、18、21)的合金薄带,研究了不同辊速(分别为12、15、20m/s)、不同成分Fe-Ga合金薄带的显微组织结构和磁致伸缩性能.试验结果表明,Fe-Ga合金的显微组织及磁致伸缩性能与合金的成分和快淬时的冷却速率密切相关,辊速为12m/s时制备的Fe83 Ga17合金薄带的磁致伸缩最大,达到6.5×10-15.研究发现,所有成分的合金试样都以α-Fe的固溶体形式存在,沿薄带厚度方向晶体具有一定的取向性,大的品格畸变和薄带的形状各异对薄带的磁致伸缩有影响.     

In,Ge添加对Fe81Ga19合金磁致伸缩系数的影响

研究了Fe81(Ga1-xYx)19(Y=In,Ge;x=0,0.1)合金的相结构,微观结构和磁致伸缩性能.结果表明:铸态和淬火态Fe81Ga19为A2相单相结构,微观组织是均匀的等轴晶;添加In后,合金由A2和富In相两相组成,富In相呈细小的颗粒状沿晶界分布,淬火后,富In相数量减少;添加Ge后,合金保持了A2相结构,晶格常数减小,铸态Fe81(Ga09Ge01)19合金中存在大量的枝晶,淬火后枝晶消失,成为均匀的等轴晶.铸态Fe81Ga19合金的磁致伸缩系数为3.3 ×10-5,淬火后提高到了7.2 ×10-5;添加In后,合金的磁致伸缩系数降低,淬火态Fe81(Ga0.99In0.1)19合金的磁致伸缩系数较热处理前提高了约1倍;添加Ge后Fe-Ga合金的磁致伸缩系数降低,与铸态Fe81(Ga0.9Ge0.1)19合金相比,淬火后磁致伸缩系数提高了约2倍.     

Al替代Fe对<110>取向Tb-Dy-Fe合金显微组织、磁致伸缩性能和力学性能的影响

采用区熔定向凝固方法制备<110>取向的Tb0.3Dy0.7(Fe1 xAlx)2(x=0,0.05,0.10,0.15)超磁致伸缩合金,研究不同含量Al原子替代Fe原子对于合金微观组织、磁致伸缩性能和力学性能的影响。结果表明:Al原子替代不改变定向凝固样品形成的<110>轴向择优取向,合金依然保持MgCu2型立方Laves相和部分稀土相结构。随着Al含量的增加,黑色RE(FeAl)2相和白色富稀土RE(Al)相的析出数量、尺寸及分布发生变化。微量Al原子(x≤0.05)替代可以显著提高材料低磁场下的动态响应及饱和磁致伸缩系数,随着Al含量进一步提高,合金系饱和磁致伸缩系数降低。Tb0.3Dy0.7(Fe1 xAlx)2(x=0,0.05,0.10,0.15)合金的压缩强度随着Al原子含量增加而增加,合金发生解理断裂。当Al替代量x≤0.1时,合金具有良好的综合性能。     

基于BP神经网络的Fe-Ga合金磁致伸缩性能预测

研究了Fe-Ga合金在铸态和油淬态时元素B对Fe-Ga合金磁致伸缩性能的影响。依据采集到的合金磁致伸缩值,使用基于遗传算法优化后的BP神经网络,预测了该合金的磁致伸缩性能。结果表明,经过遗传算法优化网络的权值后,预测误差均在4%以内,可以实现对Fe83Ga17合金磁致伸缩性能的预测。     

Tb0.3Dy0.7(Fe1-xPtx)1.95合金的结构与磁致伸缩特性研究

利用XRD、SEM和电阻应变片等方法研究了Tb0.3Dy0.7(Fe1-xPtx)1.95(x=0.00,0.02,0.04,0.06,0.08)合金的微结构和磁致伸缩特性.结果表明:当Pt含量x≤0.06时,合金为具有立方MgCu2型结构的Laves单相,Pt置换Fe导致合金相的晶格常数α线性增大;磁致伸缩系数λ随Pt含量的增加不断减小,随外磁场(H≤500mT)的增大而单调增大;当合金在950℃退火4 h,可获得较好的磁伸缩性能.在x=0.08时,合金中出现微量第二相Fe3Dy,证实Pt在Tb0.3Dy0.7Fe1.95合金中的最大固溶度小于5at%.     

Tb0.3Dy0.7Fe1.95-xNbx (x=0, 0.03, 0.06, 0.09) 合金的组织与磁致伸缩性能

采用高真空电弧炉制备了Tb0.3Dy0.7Fe1.95-xNbx(x=0,0.03,0.06,0.09)合金,研究了该系列合金的晶体结构、微观组织及磁致伸缩性能。结果表明:添加Nb元素后的Tb0.3Dy0.7Fe1.95-xNbx(x=0.03,0.06,0.09)合金基体相结构仍保持为MgCu2(C15型)立方Laves相,添加Nb后Tb0.3Dy0.7Fe1.95-xNbx合金基体相晶格常数几乎不变。Nb在基体相RFe2中和富Re相中都不溶,但在x=0.03时的RFe3相中微溶而形成Re(Nb,Fe)3相。初生相NbFe2(C14型)相的形成使凝固液体富稀土从而抑制了RFe3有害相形成。六方结构的NbFe2在与自身结构不同的RFe2(C15型)中不溶而单独成为一相存在于RFe2基体上。Nb的添加量x对磁致伸缩的影响很大,微量(x=0.03)Nb的添加有效抑制了RFe3有害相的生成而使得磁致伸缩性能提高最大,但当Nb含量继续增大时,由于顺磁相NbFe2和富Re相的析出影响了基体磁-弹性交互作用而使磁效伸缩性能下降。但相对于Tb0.3Dy0.7Fe1.95母合金都有少量提高。     

Effect of Dy doping on magnetostrictive and mechanical properties of Fe83Ga17 alloy

Fe_(83)Ga_(17) alloy is a kind of promising magnetostrictive alloys with high magnetostrictive properties and a low saturation magnetic field. As-cast Fe_(83)Ga_(17) Dyx(x=0, 0.05, 0.1, 0.2, 0.4) polycrystalline alloys were prepared by arc melting. Effect of Dy doping on the microstructure, magnetostrictive and mechanical properties of as-cast Fe_(83)Ga_(17) alloy was investigated. Results show that Dy-doped alloys exhibit a dual-phase structure containing the A2 matrix and Dy-rich precipitates(Fe_(56)Ga_(34)Dy_(10)). Both magnetostriction and mechanical properties of Fe_(83)Ga_(17) alloys are improved by Dy doping. A small amount of Dy addition(x=0.2) significantly causes Fe_(83)Ga_(17) alloy to transform from typical brittle material(fracture strain ε1%) to plastic material(ε≈11%). Correspondingly, the fracture mode transforms from intergranular fracture to dimple fracture. At the same time, the ultimate tensile strength and the magnetostriction rise up to 209 MPa and 64 ppm, respectively. Dy-rich precipitates disperse along the grain boundries and inside the grains, which plays an important role in the grain refinement and solution strengthening, and therefore, contribute to the enhancement of mechanical properties of the alloy. The improvement of magnetostriction could be attributed to the large lattice distortion induced by Dy atoms entering into the A2 matrix. Doping Dy into Fe-Ga alloys provides an effective solution to the brittleness in their applications.     

MAGNETOSTRICTIVE BEHAVIOUR OF R（Fe_（1－x）Al_x）_y ALLOYS（R＝Dy_（0．65）Tb_（0．25）Pr_（0．1））

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Tb0.3Dy0.7Fe1.95-xTix（x=0,0.03,0.06,0.09）合金的微观组织与磁致伸缩性能

利用高真空非自耗电弧炉制备了Tb_0.3Dy_0.7Fe_1.95-xTi_x（x=0,0.03,0.06,0.09）合金,系统研究了不同Ti含量Tb_0.3Dy_0.7Fe_1.95-xTi_x合金的晶体结构、微观组织、磁致伸缩性能及它们之间的关系.结果表明:添加Ti后的Tb_0.3Dy_0.7Fe_1.95-xTi_x合金基体相仍为MgCu₂型Laves相结构,Ti取代了Tb_0.3Dy_0.7Fe_1.95合金中比其自身半径大的稀土原子Tb和Dy而使晶格常数减小.添加Ti后,初生相TiFe₂的形成使得凝固液体中富含R（R=Tb,Dy）从而抑制了有害相RFe₃的生成,Ti在基体相RFe₂中和富R相中都可溶解,分别形成了（R,Ti）Fe₂基体相和富（R,Ti）相.Ti的添加量对磁致伸缩性能的影响很大,当x=0.03时,Ti的添加使磁致伸缩性能较Tb_0.3Dy_0.7Fe_1.95母合金提高幅度最大,但当x=0.09时,由于顺磁相TiFe₂和富（R,Ti）相的析出对磁致伸缩性能不利,但相对于Tb_0.3Dy_0.7Fe_1.95母合金也有少量提高.     

Pr0.3TbxDy0.7-xFe1.9Ti0.1合金结构和磁致伸缩

采用电弧熔炼方法制备了Pr0.3TbxDy0.7-xFe1.9Ti0.1(x=0.18～0.21)合金,对样品进行不同条件退火处理,并测量了其磁性能。结果表明:退火前样品都有杂相,并且第二相很大程度上影响样品磁致伸缩;700℃,6d退火处理没有有效消除杂相,样品磁致伸缩没有明显得到改善;而900℃,3d退火处理有效地消除了样品的杂相,尤其是x=0.21的样品,几乎呈现完美的单一的MgCu2型Laves相,磁化强度和磁致伸缩系数均有所增加,当磁场为900kA/m时该样品磁致伸缩系数达到了1.12×10-3。     

PHASE RELATIONSHIPS IN R－Fe PSEUDOBINARY SYSTEM （R＝Dy_（0．65）Tb_（0．25）Pr_（0．1））

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Structure and magnetic properties of mechanically alloyed Tb0.2Pr0.8(Fe0.4Co0.6)1.93 and magnetostriction of its epoxy composite

The C15 Laves phase with composition Tb0.2Pr0.8(Fe0.4Co0.6)1.93 was synthesized by mechanical alloying (MA) and subsequent annealing process. The structure and magnetic properties of Tb0.2Pr0.8(Fe0.4Co0.6)1.93 were investigated by means of X-ray diffraction (XRD), a vibrating sample magnetometer, and a standard strain technique. The effect of annealing on the structure and magnetic properties was studied. The analysis of XRD shows that the high Pr-content Tb0.2Pr0.8(Fe0.4Co0.6)1.93 alloy with the single phase of MgCu2-type structure can be success-fully synthesized by MA method. The sample annealed at 450℃ is fotmd to have a coercivity of 196 kA/m at room temperature. An ep-oxy/Tb0.2Pr0.8(Fe0.4Co0.6)1.93 composite was produced by a cold isostatic pressing technique. A large magnetostriction of 400 ppm, at an ap-plied magnetic field of 800 kA/m, was found for the composite. The epoxy-bonded Tb0.2Pr0.8(Fe0.4Co0.6)1.93 composite combines a high mag-netostriction with a significant coereivity, which is a promising magnetostrictive material.     

Fabrication,magnetostriction properties and applications of Tb-Dy-Fe alloys：a review

As an excelent giant-magnetostrictive material, Tb-Dy-Fe aloys (based on Tb0.27-0.30Dy0.73-0.70Fe1.9-2 Laves compound) can be applied in many engineering ifelds, 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 aloying elements. One is to partialy 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 MgCu2-type Laves phase and a certain amount of Re-rich phase, which can reduce the brittleness and improve the corrosion resistance of the aloy. This paper systemicaly introduces the development, the fabrication methods and the corresponding preferred growth directions of Tb-Dy-Fe aloys. In addition, the effects of aloying elements and heat treatment on magnetostrictive and mechanical properties of Tb-Dy-Fe aloys are also reviewed, respectively. Finaly, some possible applications of Tb-Dy-Fe aloys are presented.     

新型磁致伸缩材料Fe-Ga合金的研究现状

本文主要介绍了新型磁致伸缩材料Fe-Ga合金近几年的研究进展.已有的研究表明,Fe-Ga合金强度高,韧性好,脆性小,具有良好的延展性,较好的温度特性,较低的饱和磁化场以及较高的磁致伸缩应变,另外还有低廉的价格,使Fe-Ga合金在磁致伸缩器件的应用领域具有广阔的前景.