材料期刊网

THE PREPARATION AND APPLICATION OF ELECTROPLATED SHEET CONTAINING RS ALUMINUM ALLOY POWDERS

Y.S. Dong and P.H. Lin (Department of Mechanical Engineering , Southeast University , Nanjing 210096 , China) J. Shen and Q.C. Li (School of Materials Science and Engineering , Harbin Institute of Technology , Harbin 150001 , China)

金属学报(英文版)

Baded on the study of nickel electroplating technology at room temperature, the plated sheet containing rapidly solidified Al-Fe-Cu- V-Si-Ni-Ce-Zr aluminum alloy powders is constructed successfully. The powders and nickel matrix are combined well in the sheet. It can be used to prepare the observation specimen for TEM and determine the hardness of single powder particle as solidified and after heat-treated. The advantages of this method are the realization of heat treatment of powders and the TEM observation of non-interfered microstructure of powders in the size of several microns.

关键词: aluminum alloy powder electroplating , null , null

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

Z.Q. Hu , W.R.Sun and S.R. Guo(Institute of Metal Research , Chinese Academy of Sciences , Shenyang 110015 , China Manuscript received 26 August 1996)

金属学报(英文版)

The effects of the trace elements, P, S and Si,on the solidification, segregation,microstructure and mechanical properties of GH761 and In718 alloys were studied.It 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 alloy.The refinement of P in In718 alloy causes the appearance of a film-like δphase.Si 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 , null , null , null

Corrosion of Y, Fe and Fe-15Y in H_2-H_2S Mixture under 10~(-3) Pa S_2 at 600～800℃

Yan NIU , Weitao WU and Chaoliu ZENG (State Key Lab. for Corrosion and Protection , Institute of Corrosion and Protection of Metals , Chinese Academy of Sciences , Shenyang 110015 , China)F. Gesmundo and F. Viani (Instituto di Chimica , Facolta di Ingegneria , Un

材料科学技术（英）

The corrosion of an Fe-based alloy containing 15 wt pct Y in H2-H2S mixtures under 10-3 Pa S2 was studied at 600~800℃ in an attempt to find materials with improved sulphidation resistance with respect to pure Fe. The presence of Y has been shown to be beneflcial, but not sufficient to the level expected. In fact, the alloy is able to form at all tested temperatures an external FeS layer, beneath which a zone containing a mixture of the two sulphides is also present. Thus,Fe can still diffuse through this region to form the outer FeS layer with non-negligible rate. The corrosion rate of Fe is considerably reduced by the Y addition. but the alloy corrodes still much more rapidly than Y. The sulphidation kinetics is generally rather irregular for both the pure metals, while the corrosion rate of the alloy decreases with time and tends to become parabolic after an initial period of 12~17 h. The sulphidation behaviour of the alloys is discussed by taking into account the presence of an intermetallic compound Fe17Y2 and the limited solubility of Y in Fe

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Corrosion of Y, Fe and Fe-15Y in H-2-H2S mixture under 10(-3) Pa S-2 at 600 similar to 800 degrees C

材料科学技术（英）

The corrosion of an Fe-based alloy containing 15 wt pet Y in H-2-H2S mixtures under 10(-3) Pa S-2 was studied at 600 similar to 800 degrees C in an attempt to find materials with improved sulphidation resistance with respect to pure Fe. The presence of Y has been shown to be beneficial, but not sufficient to the level expected. In fact, the alloy is able to form at all tested temperatures an external FeS layer, beneath which a zone containing a mixture of the two sulphides is also present. Thus, Fe can still diffuse through this region to form the outer FeS layer with non-negligible rate. The corrosion rate of Fe is considerably reduced by the Y addition, but the alloy corrodes still much more rapidly than Y. The sulphidation kinetics is generally rather irregular for both the pure metals, while the corrosion rate of the alloy decreases with time and tends to become parabolic after an initial period of 12 similar to 17 h. The sulphidation behaviour of the alloys is discussed by taking into account the presence of an intermetallic compound Fe17Y2 and the limited solubility of Y in Fe.

关键词: high-temperature sulfidation;most-reactive component;ni-nb alloys;h2-h2s mixtures;behavior;600-degrees-c-800-degrees-c;oxidation

SULFIDATION OF Co-15wt%Y ALLOY IN H_2-H_2S MIXTURES AT 600-800℃

NIU Yan , F.GESMUNDO , WU Weitao , ZENG Chaoliu , F.VIANI , (State Key Laboratory for Corrosion and Protection , Institute of Corrosion and Protection of Metals , Chinese Academy of Sciences , Shenyang.110015 , China)(Istituto di Chimica , Facolta'di Ingegneria , Universita'di Genova , Fiera del Mare , Pad.D , 16129 Genova , Italy)Manuscript received 3 July 1995

金属学报(英文版)

The corrosion properties of a Co-15wt% Y alloy were studied in H_2-H_2S mixtures under a sulfur pressure of 10-3 Pa at 600-800℃ and of 10-2 Pa at 800℃ to examine the effect of Y on the resistance of pure cobalt to sulfur attack at high temperatures.The alloy is nearly single-phase.containing mostly the intermetallic compound Co17Y2 plus a little amount of the solid solution of Y in cobalt.At 600-700℃ and at 800℃ under 10-2 Pa of S2 the alloy forms multi-layered scales consisting of an outer region of pure cobalt sulfide,an intermediate region of a mixture of the sulfides of the two metals and finally an innermost layer of a mixture of yttrium sulfide with metal cobalt.At 800℃ under 10-3Pa of S2,below the dissociation pressure of cobalt sulfide, the alloy forms only a single layer composed of a mixture of metallic cobalt with yttrium sulfide.Pure Y produces only the oxysulfide Y2O2S, as a result of the good stability of this compound and of the presence of some impurities in the gas mixtures used The corrosion kinetics is generally rather complex and irregular except al 800℃under 10-3 Pa of S2.The addition of yttrium always reduces the sulfidation rate of cobalt, even though the formation of a continuous protective external layer of yttrium sulfide is never achieved.The internal sulfidation of Y in Co-15% Y is not associated with a depletion of Y in the alloy.This kind of diffusionless internal attack is typical of alloys with a very small solubility of the most reactive component Y in the base metal A.which restricts severely the Y flux from the alloy towards the alloy-scale interface.

关键词: :cobalt-yttrium alloy , null , null

Mechanical Properties of Simple s-p Metals, and Defect Energies from Electron Theory and from Interatomic Force Laws

N.H.March(Oxford University , Oxford , U.K.)

材料科学技术（英）

The cleavage force F(z) needed to separate parallel atomic planes by a distance z is first discussed for simple s-p metals using density functional theory.For the s-p nearly free-electron metals the linearized Thomas-Fermi equation is solved self-consistently in the cases of (a) semi-infinite planes of jellium (i.e. smeared uniform positive ions) and (b) a semi-infinite cylinder of finite radius, cleaved by a plane perpendicular to its axis. In (a), the elastic region has the form F(z)=Az ∝ Zrs-11/2, where rs is the mean interelectronic distance in the jellium model. Size effects are then considered, with possible relevance to atomic force microscopy.Defect energies are treated, using both electron theory and pair force laws.

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Department of Metallurgy and Materials Engineering of Chongqing University

YAN Guangting Chongqing University , Sichuan , China.

材料科学技术（英）

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高含H₂S/CO₂环境中P110钢应力腐蚀

崔世华 , 李春福 , 王朋飞 , 邓洪达

中国腐蚀与防护学报

用恒载荷拉伸法，结合腐蚀电化学测试技术和断口扫描电镜（SEM）分析技术，研究了P110钢在H₂S/CO₂NACE标准溶液中的硫化物应力腐蚀 (SSCC)行为。结果表明，随着溶液中的H₂S含量增高，P110钢的自腐蚀电位（E _corr}）急剧下降，至极小值后缓慢升高，约5 h后达到稳定值直至断裂，试样呈解理状脆性断口；随溶液中通入CO₂量的增大，P110 钢的自腐蚀电位（E_corr）稍有增高，自腐蚀电流（I_corr}）减小，试样断裂时间延长，断口由脆性解理向韧窝状韧性转化。这种现象的产生与H₂S/CO₂在钢表面的竞争吸附及P110钢在应力腐蚀环境中表面膜的拉伸破裂与再生有关。

关键词: P110 , H₂S/CO₂ , sulfide stress corrosion cracking

Chemical bonding and mechanical properties of M(2)AC (M = Ti, V, Cr, A = Al, Si, P, S) ceramics from first-principles investigations

Journal of Materials Research

MAX-phase carbides (M is an early transition metal, A is an A-group element) exhibit an interesting bonding characteristic of alternative stacking of strong M-C bonds and relatively weak M-A bonds in one direction. In the present first-principles total energy calculations, we establish the relationship between mechanical properties and electronic structure for ternary M(2)AC (M = Ti, V, Cr. A = Al, Si, P, S) carbides. By systematically tuning elements on the M and A sites, pronounced enhancements of bulk modulus, elastic stiffness, and ideal shear strength are achieved in V-containing V(2)AC (A = Al, Si, P, and S) carbides. It is suggested that tailoring on the A site is more efficient than on the M site in strengthening the mechanical properties of studied serial carbides. The results highlight a general trend for tailor-made mechanical properties of ternary M(2)AC carbides by control of chemical bonding.

关键词: strength;solids;shear;dislocations;ti3sic2

P110钢在CO₂/H₂S环境中的适用性研究

韩燕 , 赵雪会 , 白真权 , 尹成先

腐蚀科学与防护技术

采用高温高压实验设备辅以失重法, 研究了CO₂/H₂S腐蚀环境中P110钢的腐蚀性能, 用SEM、EDS和XRD等分析了腐蚀产物. 分别用电化学充氢及NACE TM0177 A法对P110钢进行耐氢损伤试验. 结果表明, 虽然P110钢在试验环境中的均匀腐蚀速率很小, 未发生点蚀, 但随着充氢量的增加, 强度、伸长率及断面收缩率均降低. 充氢量达到一定程度时, 材料由韧性断裂转变为脆性断裂. P110钢未通过NACE TM0177标准A法对应力腐蚀开裂性能的检测. 因此, 当井下环境中含H₂S时, P110钢的使用安全性有待进一步提高.

关键词: 腐蚀评价 , hydrogen damage , stress corrosion , CO₂/H₂S corrosion , corrosion rate