LUO Chengping(C.P.Luo) ZHAO Fang South China University of Technology
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Guangzhou
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China
金属学报(英文版)
A TEM investigation was made on the morphology,orientation relationship and habit plane of three alloy nitrides,namely CrN,VN and Mo_2N simultaneously formed within the diffussional nitrided layers in an H13 steel nitrided at 580℃.It was.found that the nitrides were precipitated by continuous clustering and subsequent ordering of both interstitial(N)and substitutional(Cr,V,Mo)solutes on {001} habit plane,and that the observed morphology and crystallography of the nitrides were in good agreement with the predictions from the invariant line stain model proposed for precipitation transformations.
关键词:
alloy nitride
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LIANG Yong LI Ruiguo Institute of Metal Research
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Academia Sinica
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Shenyang 110015
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ChinaInstitute of Corrosion and Protection of Metals
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Aademia Sinica
,
Shenyang
,
110015
,
China
材料科学技术（英）
Recent advances in laser coating technology including laser cladding,laser surface alloying and laser vapour deposition in China are reviewed in this paper.
关键词:
laser
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QIAO Lijie LIU Rui XIAO Jimei University of Science and Technology Beijing
,
Beijing
,
China
金属学报(英文版)
The effects of stress components on nucleation sites and propagation directions of stress cor- rosion cracks in brass were investigated with specimens under mode Ⅱ and mode Ⅲ loadings. The results indicated that under mode Ⅱ loading,stress corrosion cracks nucleated on the site with maximum normal stress component and propagated along the plane perpendieular to the maximum normal stress,under mode Ⅲ loading,the stress corrosion crack was not evident on the 45°plane due to the general corrosion in aqueous solution with high NH_4OH concentra- tion,while stress corroded in aqueous solution with low NH_4OH concentration, numerous cracks with spacings of 10—150μm were found on the 45°plane with maximum normal stress and no stress corrosion cracks was observed on the plane with maximum shear stress.
关键词:
stress corrosion cracking
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Journal of Materials Processing Technology
This paper has studied systematically the preparation technology and its effects on the structure and amorphous forming region (AFR), and theoretical description of the AFR for electroless Ni-P alloys. It has been found that the deposition rates increase and approach a maximum value and then decrease with the increase in the concentration of nickel chloride, sodium hypophosphite and pH value, respectively. However, the deposition rates decrease with the increase in sodium citrate. The AFR is P > 9-10 at.% in the range of concentration of nickel chloride studied. In the ran-e of concentration of sodium hypophosphite studied, there was no crystalline structure observed. The AFR calculated theoretically using the Miedema model was in good agreement with the experimental results. (C) 2002 Elsevier Science B.V. All rights reserved.
关键词:
electroless Ni-P alloys;preparation technology;structure;amorphous;forming region;Miedema model;formation enthalpies;nickel deposition;mechanism
L.L.Wang
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L.H.Zhao
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W.Y.Hu
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X.L.Shu
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X.J.Yuan
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B.W.Zhang and X.Sheng Department of Applied Physics
,
Hunan University
,
Changsha 410082
,
China
金属学报(英文版)
Manuscript received 24 June 1999 The Fe Al P alloy deposits were plated on copper sheets by electroless plating. The change law of the deposition rate, composition, surface appearance and structure for the deposits was studied by changing the metallic salt ratios (AlCl 3/AlCl 3+FeSO 4), the concentration of metallic salt AlCl 3 and reductant NaH 2PO 2. The optimum plating bath was obtained. It was found that the choices of ligand and reductant were the key of increasing Al content for the deposits.
关键词:
electroless Fe Al P plating
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Min ZHAO
材料科学技术（英）
TiB2P/Al composite was successfully fabricated by squeeze casting technology. Its mechanical and tribological properties were evaluated. The elimination of Ti-Al intermetallic compound was confirmed by X-ray diffraction (XRD) studies. At 45% volume fraction, the bending strength at ambient temperature was 934 MPa. And the fracture modes included ductile failure of Al matrix and brittle fracture of TiB2 particles. In dry sliding wear mode, severe plastic deformation and adhesive wear were found on the worn surfaces of the SiCP/Al composite. But no obvious characteristics of adhesion or abrasion wear were observed on that of the TiB2P/Al composites. At the steady stage, the friction coefficient of the SiC2P/Al composite was about 0.6. While that of TiB 2P/Al composite was only about 0.16~0.17.
关键词:
TiB2
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