Om Prakas Pandey(School of Basic and Applied Sciences
,
Thapar Institute of Engineering & Technology
,
Patiala-147001
,
India)
材料科学技术（英文）
Al-4.5Cu-5Pb alloy was prepared by sand and chill casting. The same alloy was also spray deposited at a gas pressure of 1.6 MPa. The microstructural features exhibit a coarse to fine dendritic morphology for sand and chill cast alloys. Equiaxed grains were observed for spray fOrmed alloys. Wear testing employing a pin-on-disc type set-up, reveaIs considerably lower wear of spray deposited alloy compared to that of chill and sand cast alloys. The morphological features of wear track on specimen and debris indicated a mixed oxidative-cum-adhesive wear mechanisms for these alloys tested in the present investigation
关键词:
B.W. Wang
,
H. Shen
金属学报(英文版)
Ni-Cr System solar selective thin solid films were prepared by d.c. magnetron reactivesputtering under the atmosphere of O2 and N2. Ni-Cr alloy was chosen as targetmaterial and copper sheets as substrate. Using SEM, Spectrophotometer and Talystepto analyze the relations between the selective characteristic and the structure, theformation and the thickness of the thin films. The aim is to obtain good solar selectivethin films with high absorptance and low emittance, which is applied to flat plate solarheat collectors.
关键词:
solar selective thin film
,
null
,
null
,
null
G.C. Jiang
,
K. Tang
,
X.B. Zhang and K.D. Xu Shanghai Enhanced Laboratory of Ferrometallurgy
,
Shanghai University
,
149 Yanchang Road
,
Shanghai 200072
,
China
金属学报(英文版)
Model Investigation is the only feasible way to solve the problem about the component activities in concentrated multicomponent alloys and molten slags at present. The basic characteristic of SELF-SReM model is briefly introduced in this paper. It intends to give out the systematical value of component activities in the whole homogeneous region of a concentrated multicomponent melt, then to provide a reliable database for the description of the equilibrium conditions associated with metallurgy processes. For molten slags, the key issue is to distinguish the accuracy of thermodynamic properties in binary systems. The fundamental approach for this task is to link the microscopic bond structure and macroscopic activity based on both of the measurement of high tem- perature Raman spectroscopy and the corresponding computation simulation according to molecular dynamics and quantum chemistry.
关键词:
activity
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null
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null
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null
ZHAO Hongzhuang
,
Seokjae LEE
,
Youngkook LEE
,
LIU Xianghua
,
WANG Guodong
钢铁研究学报(英文版)
This study aims at the experimental analysis of the transformation induced plasticity (TRIP) phenomenon. Experiments are conducted in which martensite is allowed to grow under the influence of a series of externally applied stresses. The magnitude of the applied stresses is less than 67% of the yield strength of austenite σγ(Ts). Since there is no obvious difference between the transformation plasticity under tension and the compression for the lower applied stresses, only compressive stresses are applied. The results confirm that the transformation plasticity is proportional to the applied stress if the latter does not exceed 67% of σγ(Ts). The TRIPstrain, the kinetics, and their dependence on the applied stresses are studied. The comparison between calculated results and experimental results shows that the model accurately describes the phenomenon.
关键词:
applied stress;TRIP;martensite transformation;lowalloy steel
Materials & Design
It was found in a commercial single crystal superalloy CMSX-4 that preferential orientation of the gamma' rafting in dendrite core was not dependent on the sign of the applied stress sigma(A), but on the sign of the sum of the applied stress sigma(A) and a critical equivalent stress sigma(c). This critical equivalent stress sigma(c) caused by material inhomogeneity has been predicted previously; however it was first determined experimentally to be in the range 39.8-47.2 MPa in the present study. Moreover, it qualitatively demonstrated that the critical equivalent stress sigma(c) played a significant role in the creep behavior of superalloys at high temperature and low stress. (C) 2009 Elsevier Ltd. All rights reserved.
关键词:
nickel-base superalloy;temperature creep-properties;uniaxial stress;alloy;parameters;morphology;apparent
ZHAO Xinbing Zhejiang University
,
Hangzhou
,
China LCKEK Institut fur Metallkunde und Metallphysik der RWTH Aachen
,
Germany Department of Materials Scicnce and Engineering
,
Zhejiang Univer sity
,
Hangzhou 310027
,
China
金属学报(英文版)
Most of the available methods for the calculation of the three dimensional(3D)grain size dis- tribution functions(SDF)are based on the S model and lead a grave systematical error.The origin is the basic supposition of spherical grains in the S model,which does not correspond with the feature of real grains.A new model called A model is developed based on the hypothe- sis of polvhedral grains.The probability functions of the A model and the method to calculate the 3D SDFs using the A model are given in the present paper.The theoretical analyses and experimental tests have demonstrated that the A model reduces the systematical error radical- ly.It is nearly as simple as the so far used S model,but gives much better results in repro- ducing of 3D SDFs from the measured ID or 2D SDFs.
关键词:
grain size
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null
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null
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null
材料科学技术（英文）
Titanate nanowires prepared by hydrothermal treatment of TiO2 in NaOH solution have attracted intensive attentions, but the formation mechanism is still under debate. Herein, we report an in-depth study on the formation mechanism through investigating the hydrothermal behavior of various Ti-containing precursors in basic solutions, including Ti, TiN, TiO2, Ti2SnC and Ti2AlN. Based on the results by means of X-ray diffraction (XRD), transmission electron microscopy (TEM) and Raman spectroscopy, it is demonstrated that the crystal structure of the hydrothermal products is irrespective to the structure of the precursors or the types of basic solution (NaOH or KOH) in use. Alkali ions play an important role in the formation of titanate nanowires. The formation mechanism of the resultant titanate nanowires was proposed to be dissolution-crystallization mechanism.
关键词:
Titanate nanowire;Hydrothermal treatment;Ti-containing precursors;Formation mechanism;trititanate nanotubes;transformation;hydrogen;anatase;route
Jie Xie
,
Xiaohui Wang
,
Yanchun Zhou
材料科学技术（英文）
Titanate nanowires prepared by hydrothermal treatment of TiO2 in NaOH solution have attracted intensive attentions, but the formation mechanism is still under debate. Herein, we report an in-depth study on the formation mechanism through investigating the hydrothermal behavior of various Ti-containing precursors in basic solutions, including Ti, TiN, TiO2, Ti2SnC and Ti2AlN. Based on the results by means of X-ray diffraction (XRD), transmission electron microscopy (TEM) and Raman spectroscopy, it is demonstrated that the crystal structure of the hydrothermal products is irrespective to the structure of the precursors or the types of basic solution (NaOH or KOH) in use. Alkali ions play an important role in the formation of titanate nanowires. The formation mechanism of the resultant titanate nanowires was proposed to be dissolution-crystallization mechanism.
关键词:
Titanate nanowire
,
null
,
null
,
null
Journal of Physical Chemistry C
We report the controlled synthesis of four kinds of cobalt basic salts with different morphologies and colors (pink, blue, green, and lavender) using urea as a hydrolysis agent in the presence of block copolymer P123. Li2SO4 and LiCl were used as salt additives to control the type of cobalt basic, salts. It was found that the amount of urea plays a critical role in the synthesis of cobalt basic salts with different phases. Two of them exhibit interesting three-dimensional urchinlike and flowerlike morphology assembled from nanorods (pink) and nanosheets (blue), respectively. The present work suggests that it is possible to directly grow three-dimensional-ordered assemblies built from one-dimensional or two-dimensional cobalt basic salt narrostructures through a one-step aqueous solution-phase chemical route under controlled conditions.
关键词:
alpha-nickel hydroxide;superstructures;carbonate;nanoparticles;conversion;bacro4;co3o4
