O.B.Perevalova
,
M.B.Fedorischeva
,
V.E.Ovcharenko
,
Huihe SU
材料科学技术（英文）
By X-ray analysis, TEM and SEM methods the phase composition, microstructure, and deviation from stoichiometric composition were investigated for the Ni3Al intermetallic compound obtained by cast and self-propagation high-temperature synthesis under compression with followed homogenization anneal, with the Al concentration being 24.0 and 25.0 at. pct with and without B (0.5 at. pct). It was discovered that in SHS intermetallic alloys an average local deviation from stoichiometric composition is significantly more than in the cast alloy. Dependence of the local deviation from the stoichiometric composition on the distance has a zig zag nature at the level of the grain groups. Deviation from the stoichiometric composition at the boundaries of the general type is less than at the boundaries of the special type. When the intensity of boundary migrations of the general type decreases, the degree of deviation from the stoichiometric composition increases. There is correlation between the solubility of B in the crystalline lattice of the Ni3Al phase and the value of the deviation from the stoichiometric composition in the grains. When the B concentration in a solid solution increases, the deviation from stoichiometric composition decreases.
关键词:
Ni3Al
,
null
,
null
,
null
Journal of the Less-Common Metals
High-field magnetization measurements were performed on magnetically aligned samples of quasi-ternary compounds of the Pr2(Fe,M)14B series with M = Al, Ga and Si at 4.2 K in magnetic fields up to 35 T. The saturation magnetization and anisotropy constants were derived as functions of composition. The results suggest that the transition in the magnetization curves of these series is probably not a first-order magnetization process (FOMP).
关键词:
crystal;anisotropy;pr2fe14b
Journal of Applied Physics
The magnetic properties of nanocomposite multilayer magnets of the (Nd,Dy)(Fe,Co,Nb,B)(5.5)/M (M=Co,FeCo) on Ti-buffered Si substrates have been investigated. X-ray diffraction results reveal that the Nd2Fe14B-type phase in almost all the films is randomly oriented. Different thickness x (nm) for Co layers and y (nm) for FeCo layers were adopted in the multilayers. It is found that high remanence is achieved in the nanocomposite multilayer films consisting of the Nd2Fe14B-type phase and soft magnetic phase for Co with 6greater than or equal toxgreater than or equal to4 and for FeCo with 10greater than or equal toygreater than or equal to6. The enhancement of the remanence in the nanocomposite multilayer films is attributed to the exchange coupling between the magnetically soft and hard phases. Increasing the soft magnetic components results in a continuously decreasing coercivity. (C) 2002 American Institute of Physics.
关键词:
remanence enhancement;fe;films
Journal of Magnetism and Magnetic Materials
Phase constitution and magnetic properties of Nd10Fe76B4M10 and Nd10Fe76B2M12 (M = Fe,Ti,V,Cr, Mn,Co and Al) alloys prepared by mechanical alloying and subsequent annealing have been systematically studied. It is found that the components of phases in the alloys critically depend on the additive transition metals M. In all the alloys, only the addition of Ti give significant enhancement to the permanent-magnetic properties. The increase of the Curie temperature in the Ti-doped alloys with an excessively low B content implies that part of the Ti atoms may occupy crystalline sites other than the Fe sites. In all the M additive alloys, with increasing content of the additive elements, the quantity of 1:7 phase increases and that of Nd2Fe14B-type phase decreases, (C) 2000 Elsevier Science B.V. All rights reserved.
关键词:
phase constitution;structure;magnetic properties;alloys;mechanical;alloying;nd;coercivity
SUN LilingInstitute of Metal Research
,
Chinese Academy of Sciences
,
Shenyang
,
ChinaWU QiShenyang College of Technology
,
Shenyang
,
ChinaZHANG Zhiya
,
HU ZhuangqiInstitute of Metal Research
,
Chinese Academy of Sciences
,
Shenyang
,
China
金属学报(英文版)
The effect of trace element B on microstructure of directionally solidified new type Co-base superalloy is studied systematically in this paper. It is found that the addition of B makes the incipient melting temperature of the alloy decline remarkably. Compared with the alloy having a boron content of 0.05 %, the incipient melting temperature of the alloy with 0.7 % B decreases by 197℃. The primary and secondary dendrite arm spacings increase and the volume fraction of interdendritic carbides with fine microstructure becomes bigger with the enhancement of boron content. When the alloy is with 0.7wt %B, M3B2 precipitates in the interdendrites.
关键词:
horon
,
null
,
null
,
null
邢峰
,
江潮
,
何文望
金属学报
本文研究了Nd_2(Fe_(1-x)M_x)_(14)B的磁性。少量类金属原子C和Si取代部分Fe,能形成四方结构,且具有单轴各向异性。碳取代Fe,使化合物的Curie温度降低,低温下粘结体样品的内禀矫顽力减少;而Si对Fe的取代可使Curie温度升高,并在x=0.15附近达到极大值。含Si样品在0≤x≤0.10范围内,矫顽力显著增加,室温下从x=0的62.7kA/m增加到x=0.06的138.7 kA/m,并且在x=0.06附近,剩磁有一个极值,饱和磁化强度减少不多。
关键词:
Nd-Fe-B合金
,
magnetic properties
,
Curie temperature
李玉清
金属学报
在NiFeCrWMoTiAl合金断口的萃取碳复型上,观察到:合金中的硼可以减少和消除能脆化合金晶界的Ti_4C_2S_2脆性薄片;硼含量为0.025—0.050％和0.075—0.100％时,M_3B_2分别呈薄片(或枝晶薄片)状和块状;在1200℃以下温度加热时,颗粒状M_3B_2沉淀,而且薄片状M_3B_2向颗粒状M_3B_2转变。
关键词:
董琰峰
,
周石山
,
杨修春
功能材料
以V2P5为原料,采用无机溶胶-凝胶法制备出V2O5粉体,在H2气氛下热处理得到了VO2(B)粉体,再在Ar气氛下热处理VO2(B)粉体,制备出了VO2(M)粉体.采用X射线衍射(XRD)、红外吸收光谱(IR)、差热分析(DTA)等方法对样品进行了成分和结构分析,结果表明,当热处理温度为500℃、H2浓度50%时,得到VO2(B)粉体;然后,在Ar气氛下分别经过550、600、650、700℃处理1h后,VO2由B型向M型转变,700℃处理成功制备出了VO2(M)粉体.
关键词:
无机溶胶-凝胶法
,
V2O5
,
VO2(B)
,
VO2(M)
,
晶型转变
