X.B.Qin
,
S.J.Cheng
,
X.F.Bian
金属学报(英文版)
The structure of Fe-2.0 alloy melt was investigated at 1580, 1560, 1540 and 1450℃ by using an X-ray diffractometer respectively. The results showed that with decreasing temperature, the average atoms of cluster, the coordination numbers, the correlation radius and the atom density increased, whereas the pre-peak of the structure factors curve remained almost at the same position. The appearance of the pre-peak indicated that the liquid structure and the solid structure of the Fe-2.00 alloy were correlated.
关键词:
liquid structure
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null
,
null
Lizhi CHENG
,
Wei FENG
,
Xinquan DONG
,
Kuichang BAI and Kaiyuan HE (Dept. of Materials Science and Engineering
,
Northeastern University Shenyang 110006
,
China)
材料科学技术（英文）
The formation of nonequilibrium phase by mechanical alloying (MA) of Fe and B powders in a high energy vibration ball mill has been made for Fe100-xBx system with x=15. 30, 35, 45,55 and 70. By using the X-ray diffraction, magnetic measurement and M6ssbauer spectrummethods, it was revealed that the structure of the MA product varies with milling time and B contents.
关键词:
Nuclear Instruments & Methods in Physics Research Section B-Beam Interactions with Materials and Atoms
We have applied the embedded atom method (EAM). to calculate boundary concentration distributions of Ni, Al and B, and B probabilities in the "interstitial" and, the "substitutional" sites, at the Ni3Al-x at.% B (100% Ni\100% Ni) [001]/Sigma5(210)/36.87 degrees. grain boundary at the equilibrium. We propose that the bulk effects of B on the grain boundary include the positive effect on the Ni enrichment at the grain boundary, i.e. the B atoms induce Ni atoms to substitute into Al sites, the negative effect on it, i.e. the B atoms substitute into Ni sites, and the neutral effect on it, i.e. the B atoms insert into interstices in the grain boundary. Our calculations show that owing to combination of the positive effect and the negative effect, corresponding to B-enrichment increasing, the Ni-enrichment and the Al-depletion become more and more obvious, when x increases from 0.1 to 0.5. Then, corresponding to B-enrichment decreasing, the Ni-enrichment and the Al-depletion also become more and more obvious, when x decreases from 0.9 to 0.5. Thus, between low (x = 0.1) and high (x = 0.9) B bulk concentrations, there is a B bulk concentration (x = 0.5), at which the Ni-enrichment and the Al-depletion become the most obvious, even if Ni is approximately saturated. (C) 2001 Elsevier Science B.V. All rights reserved.
关键词:
computer-simulation;boron;segregation;fracture;metals;alloys
Journal of Physics D-Applied Physics
Single-phase Tb(1-x)Pr(x)(Fe(0.4)Co(0.6))(1.9)B(0.1)(0 <= x <= 1) compounds have been synthesized by arc melting and subsequent annealing at ambient pressure. The lattice parameter increases while the Curie temperature decreases linearly with increasing Pr content. The saturation magnetization at 5 and 295 K of the Tb(1-x) Pr(x)(Fe(0.4)Co(0.6))(1.9)B(0.1) compounds decreases when x <= 0.5, then increases with further increasing x. The smallest magnetostriction at room temperature (RT) for Tb(0.5)Pr(0.5)(Fe(0.4)Co(0.6))(1.9)B(0.1) is attributed to its total rare-earth moment which is close to zero, due to the antiparallel alignment of the Pr and Tb moments. The normalized RT magnetization and magnetostriction show that Tb(0.2)Pr(0.8)(Fe(0.4)Co(0.6))(1.9)B(0.1) has the smallest anisotropy, which agrees with the easy magnetization direction along < 1 1 1 > for the compounds with x <= 0.8, but along < 1 1 0 > for the compounds with x = 0.9 and 1.0.
关键词:
alloys;prfe2
Journal of Magnetism and Magnetic Materials
The C15 Laves phases with composition Nd(1-x)Pr(x)(Fe(0.35)Co(0.55)B(0.1))(2) (0 <= x <= 1) have been synthesized by arc melting and subsequent annealing. The Curie temperature T(c) and the saturation magnetizations M(s) at 5 and 295 K decrease with increasing Pr content. The linear anisotropic magnetostriction lambda(a) = lambda(parallel to)-lambda(perpendicular to) at room temperature for Nd(1-x)Pr(x)(Fe(0.35)Co(0.55)B(0.1))(2) alloys with 0 <= x <= 0.4 initially reaches a negative minimum, then increases and changes its sign with increasing magnetic field H, and the lambda(a) for the alloys with x >= 0.6 is positive and increases as magnetic field H increases. (C) 2008 Elsevier B.V. All rights reserved.
关键词:
structure;magnetic property;magnetostriction;phase;alloys;boron
Materials Letters
The embedded atom method (EAM) has been used to calculate boundary concentration distributions of Ni, Al, and B, and B probabilities in the "interstitial" and the "substitutional" sites, at the Ni3Al-x at.% B (100% Ni/100% Ni) [001]/Sigma5(210)/36.87degrees grain boundary at the equilibrium. It has been proposed by us that the bulk effects of B on the grain boundary include the main effect, that is, the B atoms induce Ni atoms to substitute into Al sites, and the sub-effect, that is, the B atoms substitute into Ni sites. In this work, it is found that at as x increases from 0.1 to 1.0, the B probability in the "interstitial" sites decreases from 97.3% to 38.8%, while that in the "substitutional" sites increases from 2.7% to 61.2%. It is also found that owing to combination of the main effect and the sub-effect, corresponding to B enrichment increasing, the Ni enrichment and the Al depletion become more and more obvious when x increases from 0.1 to 0.5. Then, corresponding to B enrichment decreasing, the Ni enrichment and the Al depletion also become more and more obvious when x decreases from 0.9 to 0.5. Thus, between low (x = 0.1) and high (x = 0.9) B bulk concentrations, there is a B bulk concentration (x = 0.5), at which the Ni enrichment and the Al depletion become the most obvious, and Ni is approximately saturated. (C) 2002 Elsevier Science B.V All rights reserved.
关键词:
grain boundary concentrations;inducing and segregating species;bulk;effects;metals;alloys;ni
GUAN Kehong WANG Jun Northeast University of Technology
,
Shenyang
,
China GUAN Kehong
,
Associate Professor
,
Dept.of Material Science and Engineering
,
Northeast Univeristy of Technology
,
Shenyang 110006
,
China
金属学报(英文版)
The magnetic moment and the magnetostriction decrease slightly with the increase of total Si+B content.A maximum of the Curie temperature appears at about 25 at.-% of Si+B.The magnetic anisotropy is uninfluential by the content of Si+B,but much influnce by the demagnetization effect of streak.A qualitative explanation of the experimental phenomenon seems to be noted by the aid of the electron transition and structure model of amorphous al- loys.
关键词:
Fe-Si-B alloy
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null
,
null
,
null
,
null
,
null
YANG Hongying SHEN Baogen YANG Linyuan GUO Huiqun Laboratory of Magnetics
,
Institute of Physics
,
Academia Sinica
,
Beijing
,
China
金属学报(英文版)
The Curie temperature increases but crystallization temperature decreases with the in- crease of Ga content,x,of amorphous(Fe_(1-x)Ga_x)_(77.5)Nd_4B_(18.5) alloys.The average magnetic moment of Fe atoms is almost a constant.By X-ray diffraction and ther- momagnetic measurements,the crystalline phases of the alloys,an unknown phase and α-(Fe,Ga)besides Fe_3 B as major one,were identified.The relationship between room temperature coercive field and Ga.content was also studied.
关键词:
magnetic properties
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null
,
null
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null
Journal of Physics-Condensed Matter
The structure, phase transformation and magnetic properties of mechanically alloyed (MA) samples of Dy(m)Fe(92-m)Z(8) (Z = C, B) (13 less than or equal to m less than or equal to 20) have been studied systematically. The tetragonal Dy2Fe14C compound can be formed within a wide composition range, 15 less than or equal to m less than or equal to 18. When m greater than or equal to 19 or m less than or equal to 14, Dy2Fe17Cx with different Curie temperatures forms accompanying the Dy2Fe14C phase. An fee structure Dy-rich phase emerges during the annealing process and its amount increases with the increment of Dy content. The composition range for the formation of Dy2Fe14B is rather narrower than that of Dy2Fe14C. When m greater than or equal to 16, Dy6Fe23 is formed. When m less than or equal to 14, a certain amount of alpha-Fe that is unreacted with Dy and C is left. No Dy-rich phase if found in the Dy-Fe-B series of alloys. The highest intrinsic coercivities obtained in Dy-Fe-C and Dy-Fe-B systems are 93 kOe and 70 kOe respectively.
关键词:
sintered magnets;iron;carbon
