Large-Deflection Deformation of Ferromagnetic Plates in Magnetic Fields

Magnetoelastic buckling and postbuckling of ferromagnetic rectangular plates with geometric nonlinearity in magnetic fields are quantitatively investigated in this paper. A numerical program combining the nonlinear finite element method with an iterative method is proposed to solve the twofold nonlinear problem. The numerical results show that the ferromagnetic plate buckles when it is in a transverse magnetic field, and it bends prior to its instability when it is in an oblique magnetic field with tiny incident angle. The deflection pattern of the plates is changed from one-wave to semiwave after they lose stability.     

Effect of Plastic Deformation on Magnetic Properties of Fe-40%Ni-2%Mn Austenitic Alloy

The effects of plastic deformation on the magnetic properties of austenite structure in an Fe-40% Ni-2 % Mn alloy is investigated by using Mossbauer spectroscopy and Differential Scanning Calorimetry （DSC） techniques The morphology of the alloy has been obtained by using Scanning Electron Microscopy （SEM）. The magnetic behaviour of austenite state is ferromagnetic. After plastic deformation, a mixed magnetic structure including both paramagnet- ic and ferromagnetic states has been obtained at the room temperature. The volume fraction changes, the effective hyperfine fields of the ferromagnetic austenite phase and isomery shift values have also been determined by Mossbauer spectroscopy. The Curie point （Tc） and the Neel temperature （TN） have been investigated by means of DSC system for non-deformed and deformed Fe-Ni-Mn alloy. The plastic deformation of the alloy reduces the TN and enhances the paramagnetic character of austenitic Fe-Ni-Mn alloy.     

含小孔铁磁平板单向拉伸的漏磁场和应力分布

 研究了含小孔铁磁平板单向拉伸时应力集中状况与漏磁场分布的关系。测量了在不同拉应力作用条件下漏磁场分布的规律。对漏磁场的分布关系、漏磁场坐标变化率的分布规律,与理论上应力、应力坐标变化率的分布关系进行了比较和分析,发现存在很有应用价值和理论价值的内在规律,可为铁磁试件应力集中程度的磁性方法检测提供借鉴作用。     

Magnetoelastic effects in amorphous alloys

The domain structure and properties of amorphous ferromagnetic alloys are studied. The magnetic properties of amorphous alloys may be effectively regulated by creating a specific quasi-structure based on magnetoelastic effects.     

Progress in Research on Solidification in a Strong Static Magnetic Field

Strong magnetic fields available from superconducting magnets are opening a way to new phenomena that could lead to new methods in materials processing including solidification. The principal research involving solidification in strong static magnetic fields is emphasizing four aspects: control of crystal orientation, convection damping, thermoelectric magnetohydrodynamics (TEMHD) and change in thermodynamics. Under high magnetic intensity, aligned structural textures are induced in both magnetic and non‐magnetic materials. Since in strong magnetic field the melt flow is suppressed by convection damping, the microstructure being formed during solidification is affected heavily; this phenomenon applies to eutectic, monotectic and peritectic alloys as well as to dendritic morphologies typical of directional solidification. If strength and orientation of a magnetic field are controlled appropriately, this strong damping effect will generate more homogeneous crystals as a result of achieving diffusion‐controlled solute transport conditions. TEMHD more easily occurs in strong magnetic fields, resulting in equiaxed crystals even under directional solidification. It is evidenced experimentally and theoretically that the thermodynamics of phase transformation and nucleation are changed by strong magnetic fields.     

冶金炉的磁场模拟

从物理模型和数学模型两方面对冶金炉的磁场模拟方法进行了论述,对各种磁场模拟方法进行了比较、分析,阐明了冶金炉的磁场模拟不仅要考虑电流产生的磁场,还必须考虑铁磁屏蔽的影响。     

Magnetic fluid separation of gold-containing products in the vibration field

New data on the process of the magnetic fluid (MF) separation, which is based on the ponderomotive effect of the magnetized separation medium—or ferromagnetic fluid (FMF) on the nonmagnetic bodies arranged in it—are obtained. The magnetization of the FMF in a nonuniform magnetic field increases the strength of the field of mass forces affecting the FMF and, as a consequence, the pressure gradient in the FMF. This phenomenon can be considered pseudoweighting of the FMF and, when controlling the magnetic field force, it can be used to separate nonmagnetic materials according to their specific weights. The behavior of the FMF in the vibration field is investigated theoretically, and the dependence of energy absorbed by it on the amplitude and frequency of vibrations is revealed. Under industrial conditions, a series of tests on separation of free gold from the products of washing the goldfields by the method of MF separation is performed. The results of these tests prove the prospects of including secondary Au-containing resources with difficult-to-recover gold in processing.     

MAGNETIC FLOCCULATION OF MINERAL FINES IN AN EXTERNAL MAGNETIC FIELD

This article highlights the magnetic flocculation of mineral fines in aqueous suspensions, including ferromagnetic and weakly magnetic minerals. The magnetic attraction between magnetic mineral particles in an external magnetic field, the stability of magnetic mineral fines in aqueous suspensions, kinetics of magnetic flocculation, and the main parameters of magnetic flocculation are discussed and summarized. Some of the experimental results are presented and the applications of magnetic flocculation to fine mineral beneficiation are briefly described.     

弱磁场下镀锌板磁性能的研究

针对冷轧生产的涂层钢板的直流磁性能进行了分析。分析结果表明,弱磁场(地磁范围)的直流磁性能,不随锌层量的变化而变化,在一定涂层重量条件下,不随钢板厚度和强度的变化而变化。     

Effect of the Geometric Parameters of a Layered Powder Composite on Its Magnetic Properties

The effect of thickness of magnetic conductor and number of electrically insulating layers on the magnetic properties in an alternating field of a layered powder-metallurgy soft-magnetic material based on iron was investigated. It was determined that increasing the thickness of the magnetic conductor and frequency of the alternating current deteriorated the magnetic properties of the material. Creation of a layered structure in which ferromagnetic layers alternate with electrically insulating layers decreased specific magnetic losses.     

A Classification Algorithm for Ground Moving Targets Based on Magnetic Sensors

A novel classification algorithm based on abnormal magnetic signals is proposed for ground moving targets which are made of ferromagnetic material. According to the effect of diverse targets on earth's magnetism, the moving targets are detected by a magnetic sensor and classified with a simple computation method. The detection sensor is used for collecting a disturbance signal of earth magnetic field from an undetermined target. An optimum category match pattern of target signa-ture is tested by training some statistical samples and designing a classification machine. Three ordinary targets are re-searched in the paper. The experimental results show that the algorithm has a low computation cost and a better sorting ac-curacy. This classification method can be applied to ground reconnaissance and target intrusion detection.     

稳恒磁场对低碳锰铌钢晶粒细化的影响

了在低碳锰铌钢的奥氏体向铁素体和珠光体墨迹的过程中外加稳恒磁场的晶粒细化作用。实验结果表明：稳恒磁场对相变过程中的晶粒细化有影响。在本的实验条件下,随上加磁场磁通密度的增大,昌粒尺寸减小。在磁通密度为１．５Ｔ时,昌粒尺寸为不加磁场时线性尺寸的６０％。强磁场作用于相变时引起的高温钢辐射散热 加是导致晶粒细化的主要原因之一。由于在稳恒磁场中低碳钢的磁导率较大,磁场的产董的晶粒细化作用使试样组织的均匀     

合金碳化物M23 C6的磁性及磁致磁性

利用第一性原理研究了碳化物M23 C6 (M=Fe,Cr)的晶胞结构、磁矩和态密度,并结合魏氏分子场理论分析了磁场作用下一些碳化物的磁致磁性.结果 显示:Fe20 Cr3 C6碳化物中的Fe3和Fe4原子连接组成稳定的晶格框架,Cr1、Cr2和C原子位于框架中心;Fe20 Cr3 C6的磁性主要来源于Fe和Cr原子的3...     

Magnetic susceptibility of an atomized 304L stainless steel powder: Particle size effect

The magnetic susceptibility of a nitrogen atomized 304L stainless steel powder is measured as function of external magnetic field intensity and particle size using the Faraday method. The dependence on field strength reveals a varying additional ferromagnetic contribution to the para-magnetic susceptibility. With increasing mean diameter of either size fractions or individual particles, it first decreases steeply to a minimum value and then increases more steadily to finally level off. This results from the precipitation of a small, size-dependent amount of primary ferrite during the atomization process, as a consequence of a modification of the solidification mode with particle diameter, i.e., with particle cooling rate. The calculated ferrimagnetic contribution of surface iron oxide is negligible.     

氯化物熔盐电解槽磁场模拟

氯化物熔盐电解槽内部磁场的稳定对电流效率的提升非常重要。以50 kA氯化物熔盐电解槽为研究对象，运用有限元软件COMSOL建立电解槽三维电磁场模型，模拟了50 kA电解槽不同平面x、y、z三个方向的磁场强度和电磁力分布特点，重点研究工艺参数对磁场强度和电磁力分布的影响。结果表明，电流增加，每个平面的磁场强度和电磁力均增加，且增幅相同；降低极距、增加电解质液面高度、增加阳极半径均会使磁场强度最大值和电磁力最大值增加。     

Magnetic properties of a powder magnetic-abrasive tool

A device for measuring the magnetic properties of powder bodies with a packed density close to the bulk density is described. The magnetic properties of porous bodies made of iron powder and of composite ferromagnetic abrasive powders of various granularities and various amounts of ferromagnetic components are measured and the magnetization curves are plotted.Institute of Problems in Materials Science, Academy of Sciences of the Ukraine, Kiev. Translated from Poroshkovaya Metallurgiya, Nos. 1–2, pp. 35–39, January–February, 1994.     

Magnetometric investigation of the decomposition of residual austenite in ROMlOF3 and R2M1OF3K8 High-speed steel powders

Conclusions The magnetic method of investigation makes it possible to estimate the relative amounts of the ferromagnetic phase in starting particles of various diameters and chemical compositions and provides a vivid qualitative picture of the decomposition of austenite during the heating and cooling of a powder. It has been established that in the starting condition fine powder particles contain the largest amount of the ferromagnetic phase. The stability of residual austenite depends on the character of heat treatment and on the grade of steel. Thus, the residual austenite of R2M1OF3K8 steel is the most stable on exposure to subzero temperatures and less stable during high temperature tempering.Translated from Poroshkovaya Metallurgiya, No. 5(257), pp. 48–51, May, 1984.     

Magnetic Field Effect on Critical Behavior of Perovskite Ferromagnet

The polycrystalline samples of La2/3Ca1/3MnO3 were prepared by a conventional solid state reaction method. The magnetizations （ZFC, FC and initial magnetization） of the polycrystalline La2/3Ca1/3MnO3 were measured with superconducting quantum interference device magnetometer. The scaling theory was employed to study the changes of critical behavior arising from the applied external field. The critical parameter β decreases with increasing the external magnetic field results in an increase in the magnitude of ferromagnetic ordering.     

高梯度磁场处理循环冷却水的机理

针对循环冷却水的水质在运行过程中常出现腐蚀、结垢、藻类繁殖而影响系统的正常运行等问题,采用高梯度磁场处理技术以达到水质稳定.通过自行组建的高梯度磁处理技术实验平台,得出了在试验工况条件下,循环冷却水电导率、pH值、浊度、COD随磁场强度的变化关系.结果表明,合适的磁场强度有利于保持水质的稳定.通过扫描电镜进一步证明,高梯度磁场对水中的胶体颗粒可以起到絮凝的作用,并保持了pH值的稳定,较大幅度地去除了浊度和COD,并且改善了水质.     

A Study of the Magnetic Properties of Intermetallic Compound RFe_(12-x)M_x

The structure and intrinsic magnetic properties of RFeM(M=V or Ti),type 1:12,have been studied bymagnetic measurement and X-ray diffraction.They are body-centered tetragonal ThMn_(12)structure.Thechanges of crystal lattice constants coincide with that of their element radii.Curie temperature is decided mainlyby the exchange interactions of 3d-3d and 3d-4f atom pairs.The data obtained by mean-field approximationagree well with experimental values.The magnetic moment coupling in these compounds for LRE isferromagnetic,and for HRE is antiferromagnetic.At low temperature,anisotropy field is decided by REsublattice.In this paper,the influence of magnetic properties of cobalt and nickel replacing iron has also beenstudied.