检索结果-南通市图书馆

Tizr-base Bulk Metallic Glass with over 50 mm in Diameter

在线全文

学校读者我要写书评

暂无评论

Journal of Materials Science & Technology 2010年第6期26卷 481-486页

作者： M. q. Tang H.F. zhang z. W. zhu H.M. Fu A.M. Wang H. Li z.q. hu Shenyang National Laboratory for Materials Science Institute of Metal Research Chinese Academy of Sciences 72Wenhua Road Shenyang 110016 China

Low-cost Tizr-base bulk metallic glasses （BMGs）（Ti36.1zr33.2Ni5.8Be24.9）100-xCux （x=5, 7 and g） with a maximum size of over 50 mm in diameter were developed by optimizing the alloy composition. The idea is initiated by selecting a particular microstructure comprising primary β-Ti dendrite and amorphous phase. Afterwards, based on this composition of amorphous phase, a class of Tizr-base bulk metallic glasses was designed step by step to reach the optimum composition range. The glass transition temperature （Tg）, initial crystallization temperature （Tx） and width of supercooled region （AT） of （***33.2Nis.8Be24.9）91Cu9 BMG are 611, 055 and 44 K, respectively. The （Ti36.1zr33.2Ni5.8Be24.9）91Cu9 BMG exhibits low density of 5.541 g·cm-3 and high compressive fracture strength of 1800 MPa, which promises the potential application as structural materials.

关键词： Tizr-base alloy Bulk metallic glass (BMG) Fracture strength

Measurements of γ/γ' Lattice Misfit and γ' Volume Fraction for a Ru-containing Nickel-based Single Crystal Superalloy

在线全文

学校读者我要写书评

暂无评论

Journal of Materials Science & Technology 2011年第10期27卷 899-905页

作者： X.P. Tan J.L. Liu X P Song T. Jin X.F. Sun z.q. hu Superalloy Division Institute of Metal Research Chinese Academy of Sciences- Shenyang 110016 China Analysis and Testing Division Institute of Metal Research Chinese Academy of Sciences Shenyang 110016 China

A conventional X-ray difFractometer has been used to determine the -y/y＇ lattice misfit and γ＇ volume fraction for a Ru-containing nickel-based single crystal superalloy at room temperature. The rocking curve was used to characterize the distribution of subgrains. The diffraction peaks obtained by w-20 scan were used to determine the γ/γ＇ lattice misfit and γ＇ volume fraction. A three peaks fitting model was proposed. The peak fitting results are in good agreement with the model. The X-ray diffraction results indicate that the nickel-based single crystal superalloy was not a perfect monocrystalline material, which is comprised of many subgrains; and each subgrain also consists of large numbers of mosaic structures. In addition, two anomalous reflection phenomena were found during the experiment and discussed with respect to their occurrence and impact on the measurement. The experimental results show that the γ/γ＇ lattice misfit and ~/r volume fraction will be various at the different regions of its dendritic microstructure. The average γ/γ＇ lattice misfit and γ＇ volume fraction of the experimental alloy are approximately-0.2% and 70%, respectively. Furthermore, the γ＇ volume fraction calculated by atom microprobe （AP） data is also basically consistent with the experimental results.

关键词： Nickel-based superalloy Microstructure X-ray diffraction Lattice misfit y' volume fraction

SOLIDIFICATION OF NICKEL-BASED SINGLE CRYSTAL SUPERALLOY BY ELECTRIC FIELD

在线全文

学校读者我要写书评

暂无评论

Acta Metallurgica Sinica(English Letters) 2005年第6期18卷 679-685页

作者： Y.S. Yang X.H. Feng G.F. Cheng Y.J. Li z.q. hu Institute of Metal Research The Chinese Academy of Sciences Shenyang 110016China

The crystal growth of a nickel-based single crystal superalloy DD3 was researched via controlled directional solidification under the action of a DC electric field. The cellular or dendrite spacing of the single crystal superalloy is refined and microsegregation of alloying elements Al, Ti, Mo and W, is reduced by the electric field. The electric field decreases the interface stability and reduces the critical growth rate of the ceUular-dendritic translation because of Thomson effect and Joule heating. The precipitation of the γ＇ phase is more uniform and the size of the γ＇ phase is smaller with the electric field than that without the electric field.

关键词： single crystal superalloy DC electric field crystal growth segregation,γ' phase

Crystallization and Hardness of Melt Spun Fe_(73)Si_(13)B_9Nb_4Cu_1 Alloy

在线全文

学校读者我要写书评

暂无评论

Journal of Materials Science & Technology 2009年第1期25卷 48-52页

作者： J.I. Akhter M. Iqbal M. Siddique M. Ahmad M.A. Haq M.A. Shaikh z.q. hu Physics Division Pakistan Institute of Nuclear Science and Technology P. O. Nilore Islamabad Pakistan Shenyang National Laboratory for Materials Science Institute of Metal Research Chinese Academy of Sciences Shenyang 110016 China Department of Chemical and Materials Engineering Pakistan Institute of Engineering and Applied Sciences P.O. Nilore Islamabad Pakistan

An alloy having composition Fe73Si13B9Nb4Cu1 was synthesized by melt spinning to investigate the kinetics of crystallization. Techniques of differential scanning calorimetry （DSC）, X-ray diffraction （XRD） and Mossbauer spectroscopy were employed to characterize the phases produced due to annealing at various temperatures. High temperature DSC revealed two stage crystallization reactions. First stage, crystallization occurs at temperature around 514℃ with the production of α-Fe （bcc） and Fe3Si phases. In the second stage, Fe2B and α-Fe （Si,Nb） phases were produced. Mossbauer results revealed the formation of Fe3Si, Fe13Si3 and Fe7Si1 in the first stage and Fe3Si, Fe13Si3, Fe2B and α-Fe （Si,Nb） phases in the second stage of crystallization. An abrupt change in average internal magnetic field was observed at 500℃. The maximum hardness value was found for the sample heat-treated at 500℃.

关键词： Amorphous alloy Crystallization Mossbauer spectroscopy Hardness

EFFECT　OF　P，S　AND　Si　ON　THE　SOLIDIFICATION，SEGREGATION，MICROSTRUCTURE　AND　MECHANICAL　PROPERTIES　IN　Fe－Ni　BASE　SUPERALLOYS

在线全文

学校读者我要写书评

暂无评论

Acta Metallurgica Sinica(English Letters) 1996年第6期9卷 443-452页

作者： z.q. hu W.R.Sun and S.R. Guo(Institute of Metal Research, Chinese Academy of Sciences, Shenyang 110015, China

The effects of the trace elements, P, S and Si,on the solidification, segregation,microstructure and mechanical properties of GH761 and In718 alloys were *** was found that the segregation of the P,S and Si can be greatly aggravated or relieved by the precipitation taking place during the solidification. In the heat treated state,P enhances the intergranular precipitation in the GH761 *** refinement of P in In718 alloy causes the appearance of a film-like δ*** increases the intergranular precipitation of the M_6C and the Laves Phase in the In718 alloy.P, S and Si play diverse roles in the tensile and the stress rupture properties of the GH761 and In718 alloys. The most striking effect is that P significantly prolongs the stress rupture lives of the GH761 and In718 alloys in a wide range of 0.00050.015 wt% .The mechanisms by which P,S and Si influence the superalloys are discussed in the text.

关键词： superalloy,segregation microstructure mechanical property

Influence of Re on the Properties of a NiCoCrAlY Coating Alloy

在线全文

学校读者我要写书评

暂无评论

Journal of Materials Science & Technology 2011年第5期27卷 408-414页

作者： J.J. Liang H. We Y.L. zhu X.F. Sun z.q. hu M.S. Dargusch X.D. Yao Institute of Metal Research Chinese Academy of Sciences Shenyang 110016 China Graduate School of Chinese Academy of Sciences Beijing 100039 China School of Materials & Mining Engineering The University of Queensland QLD 4072 Australia

MCrAIY can serve as stand-alone overlay coatings or bond coats in thermal barrier coating systems, and its properties play a vital role in determining the performance of these coating systems. In order to further understand the behavior of MCrAIY coatings, several NiCoCrAIY model alloys with different levels of Re （0.3 wt%, O wt%, and 9 wt%） were investigated. Microstructural observation showed the addition of Re promoted the precipitation of Cr-rich phases, such as α-Cr and σ. The presence of α-Cr lowered the coefficient of thermal expansion （CTE） of the coating alloys, which could reduce the CTE mismatch at the scale-metal interface. The solid solution strengthening effect of Re is responsible for an increase in Rockwell hardness of the coating alloys. But the isothermal oxidation resistance at 1100℃ was deteriorated due to the precipitation of brittle α-Cr phase, a phase of inferior oxidation resistance compared with β-NiAI and γ-Ni.

关键词： NiCoCrAIY Phase constitution Oxidation Thermal expansion behavior Hardness

STRUCTURE OF Al-Cu EUTECTIC ALLOY SOLIDIFIED IN COMPLEX FIELD OF CENTRIFUGAL AND ELECTROMAGNETIC FORCES

在线全文

学校读者我要写书评

暂无评论

Acta Metallurgica Sinica(English Letters) 1997年第2期10卷 120-126页

作者： W.q. zhang Y.F. zhu Y.S. Yang and z.q. hu (State Key Lab. of RSA, Institute of Metal Research, Chinese Academy of Sciences, Shenyang 110015,China) Inst of Metal Research Chinese Acad of Sciences Shenyang China

The effects of magnetic field on macro and microstructure of Al-CuAl2 eutectic alloy produced by electromagnetic centrifugal casting have been erperimentally investigated in the present paper. Electromagnetic stirring can lead to columnar formation in the cuter region and equiaxed in the inner, and otherwise cause the lamellae coarsened and the microstructure morphology to change from lamella to rod and then to block,if the electromagnetic stirring is intensified.

关键词： electromagnetic stirring centrifgal force Al-Cu eutectic alloy

STUDY ON STRUCTURES OF Al-CuAl_2 EUTECTIC SOLIDIFIED UNDER ELECTROMAGNETIC STIRRING

在线全文

学校读者我要写书评

暂无评论

Acta Metallurgica Sinica(English Letters) 1997年第6期10卷 461-464页

作者： W.q. zhang q.M. Liu Y.F. zhu Y.S. Yang and z.q. hu(State Key Laboratory of RSA, Institute of Metal Research, Chinese Academy of Sciences, Shenyang 110015, China) Inst of Metal Research Chinese Acad of Sciences Shenyang China

An investigation on electromagnetically-stirred solidification of Al-CuAl2 eutectic system is presented in this paper. With electromagnetic stirring in solidification, structural transition from lamellar to rod-like eutectic has been found in the as-cast structures, and provided strong stirring is applied, proeutectic growth of α-Al phase is enhanced. Moreover, the interphase spacing of eutectic is clearly increased with melt flow intensified. Numerical computation of flow field is also presented, and the effect of stirring on structural formation is discussed.

关键词： electromagnetic stirring eutectic,interphase spacing fluid flow

MICROSTRUCTURE AND MACROSEGREGATION OF Al-7%Si ALLOY SOLIDIFIED UNDER COMPLEX EFFECTS OF ELECTROMAGNETIC AND CENTRIFUGAL FORCES

在线全文

学校读者我要写书评

暂无评论

Acta Metallurgica Sinica(English Letters) 1997年第2期10卷 105-114页

作者： Y.F. zhu W.q. zhang Y.S. Yang q.M. Liu and z.q. hu (State Key Lab. of RSA, Institute of Metal Research, Chinese Academy of Sciences, Shenyang 110015,Chilla) Inst of Metal Research Chinese Acad of Sciences Shenyang China

Macrosegregations and microstructures of Al-7%Si alloy solidified under complex of fects of magnetic field and centrifugal forces are studied by means of a set of selfdesigned electromagnetic centrifugal casting (EMCC) device. It is shown that electromagnetic field (EMF) has an important effect on the macrosegregation of centrifugal casting specimen of Al-7%Si alloy in two respects: one is that there exists always a kind of convection in the liquid in front of the S/L interface caused by effect ofthe electromagnetic force; the other is that different atomic clusters of solidparticles with different physical characteristics are subjected to quite different electromagnetic (Lorentz) force. Therefore, their movements get changed. In addition, the formation process of a complex band structure consisting of primary α-Al dendrites and (α-Al+β-Si) eutectics in hypoeutectic Al-Si alloys during EMCC and the effect of EMF are discussed.

关键词： electromagnetic field (EMF) centrifugal force Al-7%Si alloy macrosegregation solidification microstructure convection