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DEFORMATION BEHAVIOR OF SPRAY–DEPOSITED La–BASED BULK AMORPHOUS ALLOY IN SUPERCOOLED LIQUID REGION

DONG Tingyi,YANG Bin,HE Jianping,ZHANG Yong,

金属学报 , 2009,
Abstract: A large sized La62Al15.7(Cu, Ni)22.3 amorphous alloy was produced by spray deposition, and its compressive deformation behavior in supercooled region was investigated. It is found that both the strain rate and test temperature significantly affect the stress–strain behavior of the amorphous alloy in the supercooled liquid region. The deformation behavior is characterized by a transformation from unsteady–state flow to steady–state flow with the decrease of strain rate or increase of heating temperature in the supercooled region. After hot extrusion at 443 K, the alloy is still amorphous and its density (5.924 g/cm3) is 96.6% of the suction-cast amorphous alloy with the same component (6.134 g/cm3) when the reduction ratio, strain rate and heating temperature are adopted as 6.25, 5×10 3 s 1 and 443 K, respectively.
Investigation of Micro Formability of Bulk Amorphous Alloy in the Supercooled Liquid State Based on Fluid Flow and Finite Element Analysis

M Cheng,SH Zhang,

材料科学技术学报 , 2009,
Abstract: Research results on the viscous flow deformation behavior of bulk amorphous alloy in different systems are reviewed. The material exhibits an ideal Newtonian fluid at a high temperature. Analytical solution of lamellar fluid flow behavior is used to discuss the viscous flow behavior of the bulk amorphous alloy in the supercooled liquid state. A material model, which describes such deformation behavior of Mg60Cu30Y10 amorphous alloy,is introduced into the finite element method of microforming process. Surface feature size was investigated and found not sensitive to the micro formability. Bulk amorphous alloy may possibly be applied to microelectro-mechanical-systems (MEMS) fabrication.
Structure and Thermal Parameters of Ni20Pd80 Alloy

S Ahmad,AB Ziya,A Aziz,ZI Zafar,

材料科学技术学报 , 2009,
Abstract: The structure and thermal parameters of Ni20Pd80 alloy were studied by X-ray diffraction(XRD). The diffraction experiments performed in the temperature range of 308-1100 K revealed that the alloy formed a face centered cubic (fcc) Al-type structure. The temperature dependence of the lattice parameters was investigated by using the Bragg line displacement method showing that the lattice parameter increases with the increase of temperature. The mean linear thermal expansion (MLTE(%)), coefficient of thermal expansion (CTE, α), the characteristic Debye temperature (θD) and mean square amplitudes of vibration were determined from XRD data. The value of Debye temperature was found to be 253 K. It was found that temperature factor was independent of the static displacements.
CRYSTALLIZATION OF AMORPHOUS Ti80Si20 ALLOY UNDER HIGH PRESSURE
高压下非晶Ti80Si20合金的晶化

WANG WEN-KUI,
王文魁

物理学报 , 1984,
Abstract: We find that the amorphous alloy Ti80Si20 wouldn't decompose into multiphases, but rather transform directly into bcc supersaturate solid solution of Ti (Si). This phenomena may be attributed to the lower elastic energy created by solid solution and the comparatively large compressibility of Ti.
The effect of pressing pressure on the magnetic properties of amorphous Co80Ni20 alloy powder  [PDF]
Simeunovi? R.,Mari?i? A.,Kalezi?-Gli?ovi? A.,Spasojevi? M.
Science of Sintering , 2006, DOI: 10.2298/sos0603283s
Abstract: The impact of amorphous Co80Ni20 alloy powder pressing pressure on magnetic properties was investigated. The powder was pressed at room temperature under pressures of 560 MPa, 1100 MPa and 1300 MPa. Investigation of magnetic properties was conducted by magnetic susceptibility measurement in temperature range from 290 K to 900 K. It has been determined that with a pressing pressure increase the magnetic susceptibility rises. The differential scanning calorimetry method showed that the crystallization process occurred in two stages and each crystallization stage was followed by a magnetic susceptibility change.
Correlation between the crystallization process and change in electron density of states in amorphous powder of the Ni80Co20 alloy  [PDF]
Ran?i? S.,Mari?i? A.,Rafailovi? L.,Spasojevi? M.
Science of Sintering , 2006, DOI: 10.2298/sos0602139r
Abstract: The method of differential scanning calorimetry (DSC) was employed to examine the crystallization process of amorphous powder of the Ni80Co20 alloy in the temperature interval from room temperature to 1000K. It is shown that the crystallization process of this alloy's powder proceeds in two stages at temperatures T1=690K and T2=790K. The relative changes in the electron density of states in the vicinity of Fermi level were determined from the changes in the slope of the thermo-electromotive force (TEMF) temperature coefficient before and after each stage of crystallization process. The obtained results show that the relative change in the electron density of states is 34.9% after the first crystallization stage and 38.9% after the second one. The changes in the specific electrical resistance of the pressed powder as a function of temperature are fully correlated with the change in the electron density of states and results of the DSC method. The observed rapid decrease in the specific electrical resistance after each crystallization stage is caused by the increase of the mean free electron path and increase in the electron density of states.
The correlation of processes of crystallization and changes of free electron density amorphous alloy powder Co80Ni20
Mari?i? Aleksa M.,Risti? Mom?ilo M.
Serbian Journal of Electrical Engineering , 2005, DOI: 10.2298/sjee0501057m
Abstract: Great attention is being given today to investigations on the capabilities and structural changes of amorphous and nanocrystal materials. Structural changes of the amorphous cobalt and nickel alloy powder obtained by electrochemical deposition were investigated in this paper. The crystallization process, as determined by the DSC method, occurred in two steps. The temperature dependence of electrical resistively and magnetic susceptibility in isothermal and non-isothermal conditions within the temperature range of room temperature to 700oC was determined for the powder samples pressed under pressure of 800 MPa. The X-ray structural examinations results correlate with those of the DSC analysis and the electrical resistively measuring.
THE METASTABLE PHASES FORMED IN AN AMORPHOUS Pd80Si20 ALLOY DURING CRYSTALLIZATION
非晶合金Pd80Si20晶化过程中的亚稳相

WU LI-JUN,GUO YONG-XIANG,WU YU-KUN,GUO KE-XIN,
吴力军
,郭永翔,吴玉琨,郭可信

物理学报 , 1987,
Abstract: By tilting the crystals formed in an amorphous Pd80Si20 alloy during crystallization in a transmission electron microscope, three phases have been determined. The metastable phase P1 has a primitive orthorhombic unit cell (a = 0.46, b = 1.37, c = 1.69nm) and its possible space group is Pnmm or P(nm21). Using the data of crystal P1 the EDP of MSII and Pd9Si2 phases reported by Masumoto et al and Duhaj at el respectively can be explained. The metastable phase F has a face-centred orthorhombic unit cell with the same values of a and b as the P1 phase but c = 1.46 nm. The phase P2 crystallized at high temperature has a primitive orthorhombic unit cell (a = 0.39, b = 0.76, c = 0.54nm).
Voltage-assisted Magnetization Switching in Ultrathin Fe80Co20 Alloy Layers  [PDF]
Yoichi Shiota,Takuto Maruyama,Takayuki Nozaki,Teruya Shinjo,Masashi Shiraishi,Yoshishige Suzuki
Physics , 2009, DOI: 10.1143/APEX.2.063001
Abstract: Growing demands for the voltage-driven spintronic applications with ultralow-power consumption have led to new interest in exploring the voltage-induced magnetization switching in ferromagnetic metals. In this study, we observed a large perpendicular magnetic anisotropy change in Au(001) / ultrathin Fe80Co20(001) / MgO(001) / Polyimide / ITO junctions, and succeeded in realizing a clear switching of magnetic easy axis between in-plane and perpendicular directions. Furthermore, employing a perpendicularly magnetized film, voltage-induced magnetization switching in the perpendicular direction under the assistance of magnetic fields was demonstrated. These pioneering results may open a new window of electric-field controlled spintronics devices.
Structural transition of Fe80Cu20 alloy induced by annealing
退火诱导亚稳态Fe80Cu20合金固溶体的结构相变

Yan Wen-Sheng,Yin Shi-Long,Fan Jiang-Wei,Li Yu-Zhi,Liu Wen-Han,Hao Lu-Yuan,Pan Zhi-Yun,Wei Shi-Qiang,
闫文盛
,殷世龙,范江玮,李玉芝,刘文汉,郝绿原,潘志云,韦世强

物理学报 , 2005,
Abstract: 利用扩展x射线吸收精细结构和x射线衍射研究了机械合金化制备的体心立方(bcc)的亚稳态Fe80Cu20合金固溶体的结构随退火温度的变化特点.结果表明,在300—873 K温度范围内,随着退火温度的升高,bcc结构物相的晶格常数近于线性降低,这主要是由于Cu原子从bcc结构Fe80Cu20合金固溶体中逐渐偏析出来,生成面心立方(fcc)结构的Cu物相所致.经603K退火后,Cu原子的平均键长RCu—Cu增加了0.003 nm左右,大约有50%的Cu原子从bcc结构的Fe80Cu20合金固溶体中偏析出来.在773 K退火后,bcc结构Fe80Cu20合金固溶体近于完全相分离,生成了bcc结构的α-Fe与fcc结构的Cu物相.
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