oalib
Search Results: 1 - 10 of 100 matches for " "
All listed articles are free for downloading (OA Articles)
Page 1 /100
Display every page Item
Superelasticity of TiPdNi Alloys with and without Rare Earth Ce Addition
Qingchao TIAN,Jiansheng WU,Yifeng CHENG,
QingchaoTIAN
,JianshengWU,YifengCHENG

材料科学技术学报 , 2003,
Abstract: Ti50.6Pd30Ni19.4 and Ti51Pd28Ni21 (Ce) alloys have been prepared under various temperatures for long time annealing. Differential scanning calorimetery (DSC), X-ray diffraction (XRD) and tensile test were employed to investigate the phase transformation behavior and superelasticity of the alloys. It has been found that the phase transformation temperature of Ti50.6Pd30Ni19.4 is about 40C higher than that of Ti51Pd28Ni21(Ce), and do not change much with different annealed temperature. Obvious superelasticity is retained in Ti50.6Pd30Ni19.4 alloy annealed at 400C for 18 h, and annealing at higher temperature shows a deterioration of this property. The Ce addition in TisiPd28Ni2i alloy significantly delays recrystallization, increases yied strength and elastic modulus, but the superelasticity is poor.
Microstructures of Ti50-0.5xNi50-0.5xCux Alloys
Ti50-0.5xNi50-0.5xCux合金的微观组织

WANG Jian,JIN Wei,CAO Mingzhou,YANG Rui,
王 剑
,金 伟,曹名洲,杨 锐

金属学报 , 2006,
Abstract: 通过对Ti50-0.5xNi50-0.5xCux(x=2,5,10,15)合金微观组织的观察和分析,得出了Cu含量对合金组织的影响规律.当x=2时,合金组织主要是NiTi(B21相,没有CuNiTi相形成;当x=5时,合金组织中开始出现少量的CuNiTi相;当x≥10时,合金组织中有呈网状分布的大尺寸的CuNiTi相.热处理会影响合金的微观组织.当x≥5时,经适当热处理后合金的NiTi相上有大量弥散分布的CuNiTi相析出.CuNiTi相析出促使合金的相变温度向低温方向移动.
Ti50+xPd30Ni20-x高温形状记忆合金的弹性行为  [PDF]
田青超,吴建生
金属学报 , 2001,
Abstract: 制备了三种Ti50+xPd30Ni20-x高温形状记忆合金,使用热分析测试了合金的相变温度发现当Ti的原子分数偏离50%时,合金的相变温度随Ti成分的升高而降低,并对这种合金的力学性能进行了测试合金在奥氏体转变结束温度以上变形仍具有形状记忆效应,应力诱发的马氏体在应力去除后不能恢复到奥氏体研究了这种合金在不同的重复加载条件下的弹性行为,实验表明,弹性回线的形状特征与加载历程有关在奥氏体转变结束温度附近加载可以获得完全的线性伪弹性;而对于处于稳定单相的试样,在重复加载的条件下也可以获得弹性滞后回线.
The formation and stability of Si1-x C x alloys in Si implanted with carbon ions
Yinshu Wang,Jinmin Li,Yunfan Jin,Yutian Wang,Guosheng Sun,Lanying Lin
Chinese Science Bulletin , 2001, DOI: 10.1007/BF03187166
Abstract: Si1-xCx alloys of carbon (C) concentration between 0.6%–1.0% were grown in Si by ion implantation and high temperature annealing. The formation of Si1-x C x alloys under different ion doses and their stability during annealing were studied. If the implanted dose was less than that for amorphizing Si crystals, the implanted C atoms would like to combine with defects produced during implantation and it was difficult to form Si1-x C x alloys after being annealed at 850°C. With the increment of implanted C ion doses, the lattice damage increased and it was easier to form Si1-x C x alloys. But the lattice strain would become saturate and only part of implanted carbon atoms would occupy the substitutional positions to form Si1-x C x alloys as the implanted carbon dose increased to a certain degree. Once Si1-x C x alloys were formed, they were stable at 950°C, but part of their strain would release as the annealing temperature increased to 1 000°C. Stability of the alloys became worse with the increment of carbon concentration in the alloys.
Electronic structure and magnetism of Fe$_{3-x}$V$_{x}$X (X = Si, Ga and Al) alloys by the KKR-CPA method  [PDF]
A. Bansil,S. Kaprzyk,P. E. Mijnarends,J. Tobo?a
Physics , 1999, DOI: 10.1103/PhysRevB.60.13396
Abstract: We present first principles charge- and spin-selfconsistent electronic structure computations on the Heusler-type disordered alloys Fe$_{3-x}$V$_{x}$X for three different metalloids X=(Si, Ga and Al). In these calculations we use the methodology based on the Korringa-Kohn- Rostoker formalism and the coherent-potential approximation (KKR-CPA), generalized to treat disorder in multi-component complex alloys.
Characterization of Al and Mg Alloys from Their X-Ray Emission Bands  [PDF]
Philippe Jonnard,Karine Le Guen,R. Gauvin,Jean-Fran?ois Le Berre
Physics , 2013, DOI: 10.1017/S1431927609090060
Abstract: The valence states of Mg-Al alloys are compared to those of reference materials (pure Mg and Al metals, and intermetallics). Two methods based on X-ray emission spectroscopy are proposed to determine the phases and their proportion: first, by analyzing the Al valence spectra of the Mg-rich alloys and the Mg valence spectra of the Al-rich alloys; second, by fitting with a linear combination of the reference spectra the Al spectra of the Al-rich alloys and the Mg spectra of the Mg-rich alloys. This enables us to determine that Al and Al3Mg2 are present in the 0-43.9 wt% Al composition range and Mg and Al12Mg17 are present in the 62.5-100 wt% Al composition range. In the 43.9-62.5% Al range, the alloy is single phase and an underestimation of the Al content of the alloy can be estimated from the comparison of the bandwidth of the alloy spectrum to the bandwidths of the reference spectra.
Entropy change at the martensitic transformation in ferromagnetic shape memory alloys Ni_{2+x}Mn_{1-x}Ga  [PDF]
V. V. Khovailo,K. Oikawa,T. Abe,T. Takagi
Physics , 2003, DOI: 10.1063/1.1556218
Abstract: The entropy change $\Delta S$ between the high-temperature cubic phase and the low-temperature tetragonally-based martensitic phase of Ni$_{2+x}$Mn$_{1-x}$Ga ($x = 0 - 0.20$) alloys was studied. The experimental results obtained indicate that $\Delta S$ in the Ni$_{2+x}$Mn$_{1-x}$Ga alloys increases with the Ni excess $x$. The increase of $\Delta S$ is presumably accounted for by an increase of magnetic contribution to the entropy change. It is suggested that the change in modulation of the martensitic phase of Ni$_{2+x}$Mn$_{1-x}$Ga results in discontinuity of the composition dependence of $\Delta S$.
Quantitative Analysis of FeMo Alloys by X-Ray Fluorescence Spectrometry  [PDF]
Sung-Mo Jung
American Journal of Analytical Chemistry (AJAC) , 2014, DOI: 10.4236/ajac.2014.512085
Abstract: A quantitative analysis method of molybdenum in FeMo alloys by X-ray spectrometry using borate fusion technique was compared with that with pressed pellet. The complete pre-oxidation of FeMo alloys for the preparation of homogeneous fused discs was achieved by employing an automated fusion machine equipped with specially designed O2-blowing nozzles, which used lithium tetra-borate as flux with the addition of lithium nitrate (LiNO3) as oxidizer. The calibration curves of Mo and Fe were used in the quantitative analysis of standard materials and unknown plant samples with satisfactory accuracy and precision, utilizing the corrections of the matrix effects and line overlap. It was confirmed that the newly proposed method of preparing fused glass discs of FeMo alloys can replace the conventional wet chemical analyses requiring the labor intensive and time consuming procedure.
Ti$_{1-x}$Au$_x$ Alloys: Hard Biocompatible Metals and Their Possible Applications  [PDF]
E. Svanidze,T. Besara,M. F. Ozaydin,Yan Xin,K. Han,H. Liang,T. Siegrist,E. Morosan
Physics , 2014,
Abstract: The search for new hard materials is often challenging from both theoretical and experimental points of view. Furthermore, using materials for biomedical applications calls for alloys with high biocompatibility which are even more sparse. The Ti$_{1-x}$Au$_x$ ($0.22 \leq x \leq 0.8$) exhibit extreme hardness and strength values, elevated melting temperatures (compared to those of constituent elements), reduced density compared to Au, high malleability, bulk metallicity, high biocompatibility, low wear, reduced friction, potentially high radio opacity, as well as osseointegration. All these properties render the Ti$_{1-x}$Au$_x$ alloys particularly useful for orthopedic, dental, and prosthetic applications, where they could be used as both permanent and temporary components. Additionally, the ability of Ti$_{1-x}$Au$_x$ alloys to adhere to ceramic parts could reduce the weight and cost of these components.
Ab initio calculation of structural and electronic properties of Al$_x$Ga$_{1-x}$N and In$_x$Ga$_{1-x}$N alloys  [PDF]
E. Lopez-Apreza,J. Arriaga,D. Olguin
Physics , 2008,
Abstract: Using the density functional theory (DFT) with the generalized gradient approximation (GGA), the structural and electronic properties of wurtzite AlN, GaN, InN, and their related alloys, Al$_x$Ga$_{1-x}$N and In$_x$Ga$_{1-x}$N, were calculated. We have performed accurate {\it ab initio} total energy calculations using the full--potential linearized augmented plane wave (FP--LAPW) method to investigate the structural and electronic properties. In both alloys we found that the fundamental parameters do not follow Vegard's law. The lattice parameters, $a, c,$ and $u$, for the Al$_x$Ga$_{1-x}$N alloy are found to exhibit downward bowing, while for In$_x$Ga$_{1-x}$N there is an upward bowing for the $a$ and $c$ parameters and a downward bowing for the internal parameter, $u$. Furthermore, we found that for both alloys, the band gap value does not follow Vegard's law. As a by--product of our electronic band structure calculations, the effective masses of the binary compounds as well as their related alloys were calculated. We show that the calculated properties for the binary compounds, as well as for the studied alloys, show good agreement with most of the previously reported results. Finally, using the frozen phonon approach, the A$_1(TO)$ mode for the different systems studied in this work was calculated. Our calculations show good agreement with experimental values reported for the binary compounds. For the ternary alloys, our calculations reproduce experimental values for Al$_x$Ga$_{1-x}$N as well as theoretical predictions for In$_x$Ga$_{1-x}$N.
Page 1 /100
Display every page Item


Home
Copyright © 2008-2017 Open Access Library. All rights reserved.