共查询到6条相似文献,搜索用时 0 毫秒
1.
Pedro Gorria Roberto Boada Alejandro Fernández‐Martínez Gastón Garbarino Ronald I. Smith Jesús Chaboy J. I. García Alonso David Martínez‐Blanco German R. Castro Mohamed Mezouar Antonio Hernando Jesús A. Blanco 《固体物理学:研究快报》2009,3(4):115-117
Structural and magnetic changes on invar Fe64Ni36 alloy (TC = 500 K) produced by mechanical milling followed by heating up to 1073 K, were investigated by neutron diffraction, magnetization measurements, X‐ray diffraction under high pressures and X‐ray absorption at both Fe and Ni K‐edges. We argue that the strain induced in the Fe64Ni36 material after this treatment mainly affects the Fe sites due to the magnetovolume coupling, the most notorious feature being the increase of the Curie temperature (ΔTC = 70 K). (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim) 相似文献
2.
Nanocrystalline Fe75Si25 powders were prepared by mechanical alloying in a planetary ball mill. The evolution of the microstructure and magnetic properties during the milling process were studied by X-ray diffraction, scanning electron microscope and vibrating sample magnetometer measurements. The evolution of non-equilibrium solid solution Fe (Si) during milling was accompanied by refinement of crystallite size down to 10 nm and the introduction of high density of dislocations of the order of 1017 m−2. During the milling process, Fe sites get substituted by Si. This structural change and the resulting disorder are reflected in the lattice parameters and average magnetic moment of the powders milled for various time periods. A progressive increase of coercivity was also observed with increasing milling time. The increase of coercivity could be attributed to the introduction of dislocations and reduction of powder particle size as a function of milling time. 相似文献
3.
S. Scudino M. Sakaliyska M. Stoica K. B. Surreddi F. Ali G. Vaughan A. R. Yavari J. Eckert 《固体物理学:研究快报》2008,2(6):272-274
The structure evolution during heating of mechanically milled single‐phase β‐Al3Mg2 has been investigated by in‐situ X‐ray diffraction. The nanoscale supersaturated Al(Mg) solid solution formed during milling transforms back to the original β‐Al3Mg2 phase through a sequence of phase transformations. At low temperatures, an increasing amount of Mg is rejected from the solid solution with increasing temperature. At intermediate temperatures, the β′‐phase, a hexagonal phase with approximate composition Al3Mg2, forms. Finally, at higher temperatures the original β‐Al3Mg2 phase is restored, indicating that the formation of the supersaturated solid solution during milling can be reversed by appropriate heat treatment. The phase transformations during heating are gradual and the temperature ranges of stability of the different structure configurations are quite large, all exceeding 50 K. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim) 相似文献
4.
G.H. Zhang N. Hosokawa Y. Adachi 《Journal of magnetism and magnetic materials》2009,321(24):4010-4016
The kinetics of ferrite transformation in a Fe-0.10mass%C-2.94mass%Mn alloy in a strong magnetic field of 8 T were studied with regard to alloying element-partitioned and partitionless growth. According to the theory of diffusion-controlled growth, the slow Mn diffusion dictates partitioned growth that occurs at a low undercooling, whereas partitionless growth at a larger undercooling is rate-controlled by fast carbon diffusion. The alloy was austenitized and isothermally reacted at temperatures that encompass the two growth modes. The nucleation and growth rates of ferrite increased at all temperatures in the magnetic field, whereas the amount of increase was somewhat greater at lower temperatures. In the region of slow growth, besides its sluggish diffusion Mn possibly destabilizes the ferrite phase due to the influence on the magnetic moment and the Curie temperature of bcc Fe solid solution, and partially offsets the accelerating effect of transformation. The temperature of transition from the slow to the fast growth is predicted to increase, due to the shift in the ferrite/austenite phase boundaries in the presence of magnetic field. 相似文献
5.
Bulk mechanical alloying (BMA) followed by hot pressing (HP) was used to prepare Mg2Si0.6Ge0.4 thermoelectric material with high densification. Starting from the elemental power mixture, the Mg2Si0.6Ge0.4 solid solution was solid‐state synthesized via BMA. In fact, the peaks for the cubic‐structured Mg2Si0.6Ge0.4 solid solution phase were detected after 300 cycles in BMA. The single phase of Mg2Si0.6Ge0.4 was synthesized at 600 cycles in BMA. Mg2Si0.6Ge0.4 showed p‐type semiconduction without doping. Effects of hot pressing conditions on thermoelectric properties were investigated. With increasing hot pressing temperature from 673 to 773 K and pressure from 500 MPa to 1 GPa, the electrical conductivity increased and the Seebeck coefficient decreased. The maximum figure of merit was obtained with the processing parameter of 600 cycles BMA and hot pressing at 773 K, 1 GPa for 1 h. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim) 相似文献
6.
Shiyue Xu Minjian Zhong Liming YuHangde Chen Zhengming HeJincang Zhang 《Journal of magnetism and magnetic materials》2006
FCC (Fe55Ni45)1−xCx supersaturated solid solution was prepared in a wide concentration range (0?x?0.9) by mechanical alloying of nanocrystalline Fe55Ni45 with graphite. The lattice constant of Fe55Ni45 increases linearly with increasing carbon content up to x=0.25. At the same time, it is found that the magnetic moment per metal atom (Fe, Ni) decreases linearly with increasing carbon content for 0?x?0.25 with a slope of 1.2 μB/at. For high carbon content, x?0.5, it is observed that the decrease of lattice constant and increase of moment per metal atom (Fe, Ni) with increasing C content, indicates that the dissolution of carbon is hindered by the high-volume fraction of graphite in the initial powder mixture. The complete amorphization of x=0.5 does not occur after the extended ball milling. The alloying effect of carbon on the magnetization is compared with other metalloid B, P, and Si in Fe- and Ni-based binary system. 相似文献