DENG Yongrui University of Science and Technology Beijing
,
Beijing
,
ChinaG.S.Ansell Colorado School of Mines
,
Golden
,
CO 80401
,
USA) Associate professor
,
Department of Materials Science and Engineering
,
University of Science and Technology Beijing
,
Beijing 100083
,
China.
金属学报(英文版)
The growth of thermoelastic martensite in a Cu-29% Zn-3% Al alloy has been investigated experimentally and theoretically.Metallographie observations showed that the growth oc- cured thermoelastically,i.e.reversibly,in the radial direction as well as in the thickening di- rection.This is not consistent with the theories of Conhen and some others.A model has been suggested to explain the thermoelasticity of the growth.The basic idea is:the elastic strain distribution is highly heterogeneous and the growth is controlled by the local elastic strain en- ergy at the growth frontier area.The calculated results from the model based on Eshelby's theory are consistent with the observations.
关键词:
thermoelasticity
,
null
,
null
Zeitschrift Fur Metallkunde
A systematic reinvestigation of the Ce-Co system was carried out using differential thermal analysis, optical microscopy, X-ray diffraction and EPMA techniques. Phase relationships, structures of the intermetallic compounds and the homogeneity ranges at high temperature of Co-rich ones as well as the solid solubility of Ce in Co have been studied. A revised Ce-Co phase diagram is presented.
关键词:
Y.Q. Chang
材料科学技术（英文）
Co doped ZnO nanowires with different Co contents have been fabricated by a chemical vapor deposition method. X-ray diffraction results show that all the samples are of single phase and crystallize in wurtzite ZnO structure. The lattice parameter a increases with increasing Co content, while the parameter c has no obvious change with increasing Co. Raman spectra show that the nonpolar E2(High) mode becomes broad and weak with the doping of Co, which indicates that the incorporation of Co causes structural disorder in the crystalline columnar ZnO lattice. The photoluminescence spectra exhibit that the position of the ultraviolet emission shifts to short wavelength and the intensity decreases with increasing Co. The green emission is affected by
two contrary factors. It is increased by the introduced defects, but suppressed by the interaction between Co doping and native defects and the later affects it more significantly.
关键词:
Co doped ZnO nanowires
Journal of the Korean Physical Society
Magnetic transport phenomena in rf sputtered AlN/Co type ten-layered discontinuous films of nanoscaled [AlN(3 nm)/Co(t nm)]...(10) with t(Co) = 1.0 similar to 2.0 nm have been investigated. The nanostructures and tunneling magnetic resistance of the samples are strongly dependent on the thickness of the Co layer. Negative tunneling magneto-resistance due to the spin-dependent transport has been observed along the current-in-plane configuration in the samples having the Co layers below 1.6 nm thick. When the thickness of Co layer was less than 1.2 nm, randomly oriented granular Co particles were completely isolated and embedded in an amorphous AlN matrix, and the films showed the superparamagnetic behavior with a high MR, value of Deltarho/rho(0) = 3.5%. As t(Co) increases, a transition from the regime of co-existence of superparamagnetic and ferromagnetic behaviors to ferromagnetic behavior was observed. The tunneling barrier "decay length for tunneling" for films having a Co layer thickness from 1.4 to 1.6 nm was measured to be in the range from 0.004 to 0.021 Angstrom(-1). An enhanced TMR. was observed after annealing which is subscribed to an increase of about 100% in activation energy for tunneling.
关键词:
tunneling;spindependent;cluster;giant magnetoresistance;multilayers;ferromagnets;transport;junctions
王立军
,
谷亦杰
,
张永刚
,
陈昌麒
稀有金属材料与工程
在Co-Al-Ti三元系中,设计并熔炼了一系列含Co(Al,Ti)/(Co)的多相合金,试图通过在脆性的B2型金属间化合物Co(Al,Ti)中引入塑性的初级固溶体(Co)来提高材料的室温塑性.通过对合金铸态和经过简单热处理态的分析,确定了Co(Al,Ti)/(Co)两相区的成分范围、相平衡和相结构状况;并通过室温压缩实验了解了合金的变形行为,对合金的进一步开发前景作出了评估.
关键词:
Co-Al-Ti三元系
,
Co(Al,Ti)/(Co)
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多相合金
Zeitschrift Fur Metallkunde
A systematic reexamination of the Er - Co system was carried out by differential thermal analysis, optical microscopy, X-ray diffraction and EPMA techniques. A revised Er - Co binary phase diagram is proposed. This binary system consists of four peritectic reactions, three reactions of congruent melting and a eutectoidal reaction. The four peritectic reactions result in the formation of Er3Co, ErCo2, Er2Co7 and ErCo5, respectively. The three congruent reactions involve the formation of almost-equal-to Er16Co9, ErCo3 and Er2Co17. The eutectoidal reaction involves the decomposition of ErCo5 into Er2Co7 and Er2Co17. There are also four eutectic reactions in this system. The solid solubility of Er in Co is extremely small.
关键词:
intermetallic compounds
材料科学技术（英文）
Exchange interaction plays an important role on magnetic properties of nanocomposite magnets consisting of hard- and soft-magnetic phases. Here the exchange interaction in the Sm-Co/Co (and Fe65Co35) magnetic films was characterized by measuring static (m(r)(H)) and demagnetized (m(d)(H)) remanence curves. According to conventional method: delta m(H)=m(d)(H) - [1 - 2m(r)(H)], the exchange interaction was evaluated. The switching fields H-p(1) and H-p, at which static (m(r)(H)) and demagnetized (m(d)(H)) remanence show the fastest change, were identified. The relative ratio eta=H-p-H-p(1)/H-p of switching fields Hp' and Hp has a linear relationship with the maximum value of delta m(H) curves, proposing an alternative way to characterize the exchange interaction.
关键词:
multilayered films;exchange interaction;switching field;magnetic;properties;multilayered films;permanent-magnets;thin-films;remanence;particulate;particles;reversal;media;noise
Caiyin YOU
材料科学技术（英文）
Exchange interaction plays an important role on magnetic properties of nanocomposite magnets consisting of hard- and soft-magnetic phases. Here the exchange interaction in the Sm-Co/Co (and Fe65Co35) magnetic films was characterized by measuring static (mr(H)) and demagnetized (md(H)) remanence curves. According to conventional method: δm(H)=md(H)- [1- 2mr(H)], the exchange interaction was evaluated. The switching fields Hp′ and Hp, at which static (mr(H)) and demagnetized (md(H)) remanence show the fastest change, were identified. The relative ratio of switching fields H0p and Hp has a linear relationship with the maximum value δmmax of δm(H) curves, proposing an alternative way to characterize the exchange interaction.
关键词:
multi-layered films
,
films
,
exchange
,
interaction
Zeitschrift Fur Metallkunde
A systematic reinvestigation of the Dy-Co system was carried out using differential thermal analysis, optical microscopy, X-ray diffraction and EPMA techniques. Seven intermetallic compounds, Dy3Co, DyCo2, Dy2Co7, DyCo5, Dy12Co7, DyCo3 and Dy2Co17, were observed. The first four compounds form peritectically and the rest melt congruently. Four eutectic reactions exist in this binary system. The crystal structures of all compounds except Dy12Co7, the homogeneity ranges of DyCo5 and Dy2Co17 at elevated temperatures as well as the solid solubility of dysprosium in cobalt were determined. Based on these findings a revised Dy Co phase diagram is proposed.
关键词:
intermetallic compounds;cobalt
Zeitschrift Fur Metallkunde
The Sm - Co binary system has been reinvestigated using differential thermal analysis, optical microscopy, X-ray diffraction and EPMA techniques. Eight compounds exist in this system, six of them (Sm9Co4, SmCo2, SmCo3 Sm2Co7, Sm5Co19 and SmCo5) are formed by peritectic reactions, and two (Sm3Co and Sm2Co17) melt congruently. Three eutectic reactions occur in this system. The high-temperature homogeneity ranges for SMCo5 and Sm2Co17 compounds as well as the solid solubility of Sm in Co have been determined.
关键词:
phase-equilibria;redetermination;850-degree-c;cu
