J. Feng
,
W.D. Huang
,
X. Lin
,
T. Li
,
Y.F. Xue and Y.H. Zhou(State Key Lab. of Solidilication Processing
,
Northwestern Polytechnical University
,
Xi'an 710072
,
China)
金属学报(英文版)
In order to investigate the response of cellular spacing to the variation of growth velocity under near-rapid directional solidification condition, Al-0.53wt%Zn alloy is directionally solidified with Bridgman apparatus. The results show that at the given temperature gradient the obtained microstrvctures are all cells and there exists a wide distribution range of cellular spacing. The maximum, λmax, minimum, λmin, and average cellular spacing, λ, as functions of growth rate, V, can be given by λmax=948.51V-0.4961, λmin= 661.16V-0.5015 and λ=412.41V-0.5049, respectively. The experimental results are compared with that predicted by KGT model, and a good agreement is found. Moreover,it is found that the average cellular spacing is also remarkably history-dependent.
关键词:
Al-Zn alloy
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null
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null
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null
Ieee Transactions on Magnetics
The microstructure, magnetic properties and magnetostriction of Tb0.2Pr0.8(Fe0.4Co0.6)(infinity) (1.65 less than or equal to x less than or equal to 1.90) alloys has been studied. The Curie temperatures for the 1:2 and 1:3 phases decrease with increasing x, whereas the saturation magnetization increases with increasing cc. The remanent magnetization remains almost constant for all the samples and the coercivity decreases with increasing x. The spontaneous magnetostriction (lambda (111)) estimated from the splitting of the (440) lines is found to decrease with increasing x. The largest lambda (111) recorded for Tb0.2Pr0.8(Fe0.4Co0.6)(1.65) is 2900 ppm at room temperature.
关键词:
Laves phase;microstructure;spontaneous magnetostriction;alloys
Y.M.Hao1) and Y.Gao2) 1)Department of Physics
,
Tianjin Normal University
,
Tianjin 300074
,
China 2)Library
,
Tianjin Normal University
,
Tianjin 300074
,
China
金属学报(英文版)
tructuraland magnetic propertiesof Ho2 AlFe16 x Mnx( x= 0 8) compoundshave been in vestigated by means of x ray diffraction and magnetization measurements. Thecompoundshave a hexagonal Th2 Ni17 typestructure. With increasing x,the unit cell volumes have a smallincreaseinitially,followed by a greaterlinearincrease. The Curietemperatureandthe saturation magnetization of these compounds show marvelous drop with increasing x. The valuesofJRTofthecompoundsfor x =2 ,3 , and 4 are given.
关键词:
unit cellvolume
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null
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null
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null
Journal of Alloys and Compounds
Pseudo-1-3 magnetostrictive particulate composites consisting of light rare earth (Sm and Nd)-based magnetostrictive Sm(1-x)Nd(x)Fe(1.55) particles with the Nd content x of 0-0.56 and randomly distributed sizes of 10-180 mu m membedded and aligned in a passive epoxy matrix are fabricated using the particulate volume fraction of 0.5. The quasistatic magnetomechanical properties of the composites are investigated and the results are compared with their monolithic alloys for various x. The composites exhibit similar qualitative trends in properties with the alloys for all x. The Sm(0.92)Nd(0.08)Fe(1.55) composite shows a large unsaturated magnetostriction lambda of -530ppm at 500 kA/m and a high piezomagnetic coefficient d(33) of -2.0 nm/A at 100 kA/m as a result of the magnetocrystalline anisotropy compensation between Sm(3+) and Nd(3+) ions in the Sm(0.92)Nd(0.08)Fe(1.55) alloy. (C) 2011 Elsevier B.V. All rights reserved.
关键词:
Light rare earths;Magnetocrystalline anisotropy;Magnetomechanical;properties;Negative magnetostriction;Magnetostrictive composites;Sm(1-x)NdxFe(1.55) alloys;terfenol-d
Journal of Alloys and Compounds
Stabilizer (B, Co)-free, light rare earth (Pr)-substituted Laves alloys (Tb(0.3)Dy(0.7))(1-x)Pr(x)Fe(1.55) (0 <= x <= 0.4) are synthesized, and their structural, magnetic, and magnetostrictive properties are investigated. X-ray diffraction analysis confirms the presence of single cubic Laves phase with an MgCu(2)-type structure in the (Tb(0.3)Dy(0.7))(1-x)Pr(x)Fe(1.55) alloys with 0 <= x <= 0.35. The lattice parameter a of the Laves phase increases, while the Curie temperature decreases, with increasing x from 0 to 0.35. The saturation magnetization of the alloys decreases with increasing x. The linear anisotropic magnetostriction lambda(a) (=lambda(parallel to) - lambda(perpendicular to)) shows a maximum of 1502 ppm at x = 0.25 as a result of the magnetocrystalline anisotropy compensation. (C) 2008 Elsevier B.V. All rights reserved.
关键词:
Alloys and compounds;Laves phase;Light rare earths;Magnetocrystalline;anisotropy;Magnetostriction;Terfenol-D;anisotropy compensation;boron
Journal of Physics D-Applied Physics
Pseudo-1-3 magnetostrictive composites consisting of stabilizer ( B, Co)-free, light rare earth (Pr)-containing magnetostrictive (Tb(0.3)Dy(0.7))(1-x) Pr(x) Fe(1.55) (0 <= x <= 0.4) particles with a size distribution of 10-300 mu m embedded and aligned in a passive epoxy matrix using 0.5 volume fraction are fabricated. The quasistatic magnetomechanical properties of the composites are investigated and compared with their monolithic (Tb(0.3)Dy(0.7))(1-x) Pr(x) Fe(1.55) alloys, as a function of the Pr content x. The composites show similar qualitative trends in properties with the alloys for all x. The (Tb(0.3)Dy(0.7))(0.75)Pr(0.25)Fe(1.55) composite and alloy exhibit the smallest coercivity H(c), the largest magnetostriction lambda and the highest piezomagnetic coefficient d(33) due to the successful compensation for magnetocrystalline anisotropy. The ( Tb0.3Dy0.7) 0.75Pr0.25Fe1.55 composite demonstrates a large saturation magnetostriction lambda(s) of 793 ppm at 700 kAm(-1) and a high d(33) of 3.2 nmA(-1) at 140 kAm(-1). These values approach 81% and 85% of its alloy values at the same field levels. The good properties make the (Tb(0.3)Dy(0.7))(0.75)Pr(0.25)Fe(1.55) composite and alloy a promising magnetostrictive material system.
关键词:
terfenol-d;magnetic-properties;alloys;boron
Journal of Magnetism and Magnetic Materials
The structure, magnetic and magnetostrictive properties of Sm(0.88)Nd(0.12)(Fe(1-x)Co(x))(1.93) (0 <= x <= 1.0) alloys have been investigated. The alloys have the cubic MgCu(2) structure over the whole composition range and the lattice parameter a decreases with increasing x. For 0 <= x <= 0.2, substitution of Co for Fe slightly increases the saturation magnetization M(s) and Curie temperature T(c), while further substitution causes a decrease in both M(s) and T(c). The spin reorientation is observed, and a phase diagram for the spin configurations of the Sm(0.88)Nd(0.12)(Fe(1-x)Co(x))(1.93) system is determined. The spontaneous magnetostriction lambda(111) increases as x is increased, while a monotonic decrease of the saturation magnetostriction lambda(s) with x originates from the increase of lambda(100) with opposite sign to that of lambda(111), which may be caused by the filling of the d band due to Co substitution. (C) 2010 Elsevier B.V. All rights reserved.
关键词:
Laves phase;Spin reorientation;Magnetostriction;giant magnetostriction;phase-compounds;temperature-dependence;anisotropy;substitution;alloys;fe
Applied Physics a-Materials Science & Processing
A series of manganites Tb(1-x) Ho (x) MnO(3) (0a parts per thousand currency signxa parts per thousand currency sign0.6) with orthorhombic structure are synthesized and detailed investigations on their multiferroicity are performed. Successive magnetic transitions upon temperature variation are evidenced for all the samples, and both the Mn(3+)spiral spin ordering and rare-earth spin ordering are suppressed with increasing x. A significant enhancement of both the polarization and magnetoelectric response within 0.2 < x < 0.4 is observed, which may probably result from the shortening of the spiral-spin-ordering period, due to the competition between the spiral spin order and E-type antiferromagnetic order. This argument is supported by further theoretical calculations based on the two e (g) -orbital double-exchange model.
关键词:
ferroelectricity;magnetism
Journal of Magnetism and Magnetic Materials
The structure and magnetostriction of preferentially oriented polycrystalline R(Fe0.95Al0.05), alloys (R = Dy0.65Tb0.25 Pr-0.1, 1.80 less than or equal to x less than or equal to 1.95) prepared by Czochralski technique, have been investigated using optical and SEM metallography, X-ray diffraction, transmission electron microscopy and standard strain gauge techniques. The alloy contains some rare earth-rich phase when x less than or equal to 1.85, however (Dy,Tb,Pr)(Fe,Al)(3) particles emerges when x > 1.85, the amount of which increases with increasing x. X-ray diffraction analysis indicated that almost all crystallites grow along [110] direction when x less than or equal to 1.85 whereas part of crystallites grows along [112] direction when x greater than or equal to 1.90. The magnetostriction along the growth direction of the samples has been assessed.
关键词:
magnetostriction;cubic Laves phase pseudobinary compounds;iron-aluminum compounds;crystals
