共查询到17条相似文献,搜索用时 171 毫秒
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铁磁性物体在地磁场中的自发"运动磁化" 总被引:1,自引:0,他引:1
依据法拉第电磁感应定律和铁磁性物质在磁化—退磁过程中的能量差异,阐明了铁磁性物体在地磁扬中的摆动、振动和周期性往复平动都会引起该物体的自发磁化。虽然每次磁化一退磁过程之后物体上的剩磁增量非常微小,但随着循环次数的增加,该物体最终必然被强烈的自发磁化。从而推知:地磁场的矢量特性和纬度效应对金属磁记忆检测与诊断技术适用性和可靠性的影响都不大。 相似文献
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铁磁性物体在地磁场中的自发运动磁化 总被引:3,自引:0,他引:3
依据法拉第电磁感应定律和铁磁性物质在磁化一退磁过程中的能量差异,阐明了铁磁性物体在地磁场中的摆动、振动和周期性往复平动都会引起该物体的自发磁化。虽然每次磁化一退磁过程之后物体上的剩磁增量非常微小,但随着循环次数的增加该物体最终必然被强烈地自发磁化。从而推知:地磁场的矢量特性和纬度效应对金属磁记忆检测与诊断技术适用性和可靠性的影响都不大。 相似文献
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磁致伸缩和磁记忆问题研究 总被引:9,自引:1,他引:9
从铁磁性材料的基本特性和最小自由能原理出发,探讨了应力和外磁场对磁性材料磁化状态的不同影响,讨论了磁致伸缩现象的规律和特点。用磁致伸缩方程组详细研究了磁记忆现象产生的条件和规律,分析了应力和地磁场在磁记忆现象中的不同作用。结论认为应力可改变材料的磁特性,地磁场则可改变材料的压磁性,两者共同作用产生净磁场,磁记忆现象不仅与应力和材料的磁特性有关,而且还与工件在空间的位置和方向有关。 相似文献
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问:为什么拉断后的铁磁性材料试棒常带有磁性? 答:这是地磁场中铁磁性材料在定向机械应力作用下发生应变磁化的结果。 由文献[1,2]知,若铁磁性材料试棒垂直于地磁 相似文献
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金属磁记忆法诊断的理论基础——铁磁性材料的弹—塑性应变磁化 总被引:22,自引:6,他引:16
电磁感应定律证明,铁磁性材料在地球磁场中的自发磁化来源于定向应力作用下材料本身的应变和交变应力作用下材料的非对称弹-塑性应变。某种铁磁性材料的自发磁化过程可由该材料的磁化和退磁曲线来估计,由此推得的磁弹性现象图与实验结果相一致。 相似文献
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《Journal of Materials Processing Technology》2007,181(1-3):165-171
This paper determines the elastic coefficients in the constitutive equations of typical ferromagnetic materials. The constitutive equations are given by rate-type equations for the magnetization and the strain expressed in terms of the magnetic field and the stress. The authors have shown that the constitutive equations can describe the stress-dependent hysteretic magnetization curve, the stress magnetization effects, the stress-dependent magnetostriction curve, etc. They have determined the coefficients except the elastic coefficients as functions of the magnetization and the stress for typical ferromagnetic materials. In this paper, we attempt to obtain the elastic coefficients depending on the magnetization and the stress. To do it, applying the magnetoacoustic effect, we measure the stress–strain curves and the speeds of the longitudinal and the transverse ultrasonic waves under the magnetic field. 相似文献
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Residual stresses in ferromagnetic material affect the direction and structure of domains and generate magnetic field abnormality on the surface.In the formation of stress induced magnetic field,the influence of geomagnetic field is unclear.Residual stress specimen was produced by tight matching of a round ring and a peg.The magnetic fields of contrast specimens,which were produced in geomagnetic field or in shielding geomagnetic field,were ingspected with 8mm lift-off.The results show that mean amplitude of magnetic field of the specimen produced in geomagnetic field is 0.85% larger than that of specimen produced in shielding geomagnetic field.So the formation of stress induced magnetic field abnormality above the surface of inspected ferromagnetic material geomagnetic field gives little contribution. 相似文献
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漏磁通检测中铁磁材料的磁化状态 总被引:3,自引:3,他引:0
讨论缺陷引起的附加磁场和外磁化场对铁磁材料的磁化作用,引入有效磁导率和平衡磁导率来描述铁磁材料不同区域的磁化状态,建立铁磁材料中的磁化状态及磁偶极子模型中的关荷密度与外磁化场强度、铁磁材料的内禀磁性质以及铁磁材料中磁路和缺陷几何尺寸的关系。 相似文献
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V. N. Kostin 《The Physics of Metals and Metallography》2009,107(1):25-33
The dependences of the ΔEeffect and internal friction on the magnetic field have been investigated upon the magnetization and magnetization reversal of some polycrystalline ferromagnetic materials with different properties. It has been shown that for all the materials that have been investigated there is characteristic a nonmonotonic dependence of the magnitude of internal friction on the magnetic field both for the magnetization curves and for the major hysteresis loops. It is shown that in the sonic frequency range of elastic vibrations the basic mechanism of the formation of the magnetic peaks of internal friction in the materials investigated is magnetostrictive; the damping depends simultaneously on the instantaneous values of magnetostriction and magnetostrictive sensitivity. 相似文献
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A. A. Ivanov V. A. Orlov G. O. Patrushev 《The Physics of Metals and Metallography》2006,102(5):485-493
Analysis is given of the effect of the dimensionality of structural inhomogeneities on the properties of the magnetic structure of ultradisperse ferromagnetic materials. The coordinate dependence of the magnetization dispersion of magnets with one-dimensional and two-dimensional inhomogeneities of magnetic anisotropy has been calculated. The linear dimension of a magnetic block for one-and two-dimensional inhomogeneities of the anisotropy field has been estimated. A method for exact calculation of the distribution function of magnetization rotations in the block is suggested. 相似文献
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This paper proposes a method of lossless micromagnetic detection in the geomagnetic field for detecting traces of carbon impurity defects in crystalline silicon. The magnetization tests show that crystalline silicon is a diamagnetic substance with a stronger relative permeability than carbon. Micromagnetic decay theory is gained according to the energy decay. When the geomagnetic field penetrates through the materials, the apparent magnetic susceptibility can be calculated and subsequently used to project the images. The resulting image clearly showed the location of the defects. Test results are proved by the metallographic phase and spectral analysis. New method and ideas are provided for effective detection of trace carbon impurity defects in the crystalline silicon. 相似文献