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[Functionally Graded Materials 1998　Proceedings of the 5th International symposium on Functionally Graded Materials (pp.794-1052)](https://mdr.nims.go.jp/datasets/c5180ff9-f904-4ddd-9b9e-5784355f8965)

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Sheet1 BookTitle_j BookTitle_e Volume/Issue Issueddate Page Title_j Title_e AuthorList_j AuthorList_e Abstract Language Functionally Graded Materials 1998Proceedings of the 5th International symposium on Functionally Graded Materials,held in New Town Hall,Dresden.Germany,october 26-29,1998 Functionally Graded Materials 1998Proceedings of the 5th International symposium on Functionally Graded Materials 6 1998-12-31 794-799 YSZ-CGO複合材料電解質中の微細構造と相互拡散現象 Microstructure and Interdiffusion Phenomena in YSZ-CGO Composite Electrolyte A. Tsoga 1, 2, A. Naoumidis 1, A. Gupta 1 and D. Stover 11 Institut fur Werkstoffe und Verfahren der Energietechnik (IWV1), Forschungszentrum Julich GmbH, DE-52425 Julich, Germany 2 TMR Grant Holder A. Tsoga 1, 2, A. Naoumidis 1, A. Gupta 1 and D. Stover 11 Institut fur Werkstoffe und Verfahren der Energietechnik (IWV1), Forschungszentrum Julich GmbH, DE-52425 Julich, Germany 2 TMR Grant Holder  In order to investigate the co-firing feasibility of a double-layer ceria-zirconia electrolyte for low-temperature Solid Oxide Fuel Cells (SOFCs), interdiffusion phenomena between yttria-stabilized zirconia (YSZ) and cerium-gadolinium oxide (CGO) were studied in the temperature range 1200deg.C to 1500deg.C with the aid of SEM/EDX-WDS. Significant solid state reaction and interdiffusion phenomena across the YSZ-CGO interface were found to occur already at 1200deg.C. The extent of the interdiffusion zone formed at the interface as well as the elemental distributions in this zone showed no dependence on sintering temperature and holding time. The difference of the diffusivity of Ce4+ and Gd3+ into YSZ and Y3+ and Zr4+ into CGO resulted in porosity emerging at the YSZ/CGO interface. The use of a microstructure with a graded YSZ/CGO0.5YSZ0.5/CGO composition was found to reduce the cation diffusion rates across the interface. However, the low conductivity of the CGO0.5YSZ0.5 solid solution phase used requires further optimization of the composition of the interlayer to be used. English Functionally Graded Materials 1998Proceedings of the 5th International symposium on Functionally Graded Materials,held in New Town Hall,Dresden.Germany,october 26-29,1998 Functionally Graded Materials 1998Proceedings of the 5th International symposium on Functionally Graded Materials 6 1998-12-31 800-805 SOFC-組成物質としての傾斜複合材料陰極の熱溶射と性能 Thermal Spraying and Performance of Graded Composite Cathodes as SOFC-Component K. Barthel 1 and S. Rambert 21 Swiss Federal Laboratories for Materials Testing and Research, EMPA, Feuerwerkerstr. 39, CH-3602 Thun, Switzerland 2 Swiss Federal Institute of Technology Lausanne, EPFL, DC, LPI, CH-1015-Lausanne, Switzerland K. Barthel 1 and S. Rambert 21 Swiss Federal Laboratories for Materials Testing and Research, EMPA, Feuerwerkerstr. 39, CH-3602 Thun, Switzerland 2 Swiss Federal Institute of Technology Lausanne, EPFL, DC, LPI, CH-1015-Lausanne, Switzerland  Porous compositionally graded composite cathodes containing (La0.8 Sr0.2)0.98MnO3 (LSM) and ZrO2-12% Y2O3 (YSZ) were prepared by vacuum plasma spraying (VPS) and flame spraying (FS) on prefabricated planar cells with 60 mm diameter. Besides microstructural observations their electrochemical behavior has been investigated by impedance spectroscopy. The results of graded cathodes compared with non-gradient- and bi-layered ones concerning the cathodic polarization resistance between 750 and 950deg.C are discussed. English Functionally Graded Materials 1998Proceedings of the 5th International symposium on Functionally Graded Materials,held in New Town Hall,Dresden.Germany,october 26-29,1998 Functionally Graded Materials 1998Proceedings of the 5th International symposium on Functionally Graded Materials 6 1998-12-31 806-813 SOFCのための傾斜複合材料電極の開発 Development of Graded Composite Electrodes for the SOFC Ch. Gerk and M. Willert-PoradaUniversity of Dortmund, Department of Chem. Eng., Div. Mater. Sci., Dortmund, Germany Ch. Gerk and M. Willert-PoradaUniversity of Dortmund, Department of Chem. Eng., Div. Mater. Sci., Dortmund, Germany  The simultaneous increase of electrochemical activity (i. e. fineness) and thermal stability of SOFC-electrodes is possible using eutectic microstructures. On the basis of a lamellar NiO-YSZ eutectic a microwave melting process was developed which allows crystallization in a large temperature gradient. The microstructures obtained by melting the electrodes directly onto the top of a YSZ substrate (electrolyte) consist of partially aligned lamellae perpendicular to the surface of the substrate. The thickness of the alternating NiO-YSZ lamellae is graded over the thickness of the electrode, i. e. it increases with increasing distance from the substrate. In terms of functionality this means an inverse gradient of electrochemical active three phase boundaries (gas-Ni-YSZ) after reduction of NiO to Ni. During the reduction process the microstructural gradient of lamellae thickness is converted into a functional gradient of electrochemical active sites. The models taken into account show that this functionally graded microstructure should lower the overpotentials of SOFC-devices. The paper concentrates on modelling and experimental details for the preparation of partially aligned eutectic lamellae with a graded interlamellar spacing. English Functionally Graded Materials 1998Proceedings of the 5th International symposium on Functionally Graded Materials,held in New Town Hall,Dresden.Germany,october 26-29,1998 Functionally Graded Materials 1998Proceedings of the 5th International symposium on Functionally Graded Materials 6 1998-12-31 814-819 気孔率傾斜炭化ケイ素蒸発器チューブを作製するための加圧ろ過プロセスのシミュレーション Simulation of Pressure Filtrating Process for Making Porosity Graded Silicon Carbide Evaporator Tubes M. Droschel, R. Oberacker and M. J. HoffmannInstitut fur Keramik im Maschinenbau-Zentrallaboratorium, Universitat Karlsruhe (TH), Haid-und-Neu-Strasse 7, DE-76131 Karlsruhe, Germany M. Droschel, R. Oberacker and M. J. HoffmannInstitut fur Keramik im Maschinenbau-Zentrallaboratorium, Universitat Karlsruhe (TH), Haid-und-Neu-Strasse 7, DE-76131 Karlsruhe, Germany  Porous silicon carbide (SiC) ceramics are promising materials for liquid fuel evaporator tubes in gas turbine combustors. Previous finite element method (FEM) calculations show that a tailored porosity gradient is necessary to meet the local stress/strength requirements. For tubes with such porosity gradients a processing route based on pressure filtration was developed. The formation of one- and more dimensional wax concentration gradients in the filter cake (corresponding to porosity gradients after sintering) is adjusted by controlling the composition of a mixture of SiC- and SiC-wax slurries and the filtration pressure. The design concept of a laboratory casting apparatus which uses this concept is presented. An experimental/numerical method for the derivation of the process parameters will also be treated in the paper. English Functionally Graded Materials 1998Proceedings of the 5th International symposium on Functionally Graded Materials,held in New Town Hall,Dresden.Germany,october 26-29,1998 Functionally Graded Materials 1998Proceedings of the 5th International symposium on Functionally Graded Materials 6 1998-12-31 820-825 有限要素計算によってデザインした気孔率勾配を伴う炭化ケイ素蒸発器チューブ Silicon Carbide Evaporator Tubes with Porosity Gradient Designed by Finite Element Calculations M. Droschel 1, R. Oberacker 1, M. J. Hoffmann 1, W. Schaller 2, Y. Y. Yang 2 and D. Munz 21 Institut fur Keramik im Maschinenbau-Zentrallaboratorium, Universitat Karlsruhe (TH), Haid-und-Neu-Strasse 7, DE-76131 Karlsruhe, Germany 2 Institut fur Materialforschung, Forschungszentrum Karlsruhe, Postfach 3640, DE-76021 Karlsruhe, Germany M. Droschel 1, R. Oberacker 1, M. J. Hoffmann 1, W. Schaller 2, Y. Y. Yang 2 and D. Munz 21 Institut fur Keramik im Maschinenbau-Zentrallaboratorium, Universitat Karlsruhe (TH), Haid-und-Neu-Strasse 7, DE-76131 Karlsruhe, Germany 2 Institut fur Materialforschung, Forschungszentrum Karlsruhe, Postfach 3640, DE-76021 Karlsruhe, Germany  Gas turbine combustors with premix burners can reduce NOx emissions. In a new premix burner concept the evaporation of the liquid fuel and the burning zone are decoupled. The liquid fuel is sprayed onto the porous outer surface of the evaporator tube. The flowing air and the fuel vapor enter the tube where the combustion takes place. The tube must be gastight on the inner surface. Inside the tube the temperature is about 1500deg.C, at the outer surface about 550deg.C. Previous work shows that application of porous silicon carbide (SiC) ceramics is rather promising.       Due to the temperature gradient both during steady state and transient operation, high thermal stresses develop in the tube. Four different design variations of porosity gradients are investigated: a two-layer concept without FGM and three continuous porosity gradients (linear, convex, concave).       By comparing the local stress distribution with the local strength of the four different design variations, a favorable porosity gradient is found. Only with this tailored porosity gradient the failure probability of the component can be kept on a tolerable level. English Functionally Graded Materials 1998Proceedings of the 5th International symposium on Functionally Graded Materials,held in New Town Hall,Dresden.Germany,october 26-29,1998 Functionally Graded Materials 1998Proceedings of the 5th International symposium on Functionally Graded Materials 6 1998-12-31 829-836 回折法による傾斜機能材料中の巨視的および微視的な残留応力の解析 Analysis of Macro and Micro Residual Stresses in Functionally Graded Materials by Diffraction Methods D. Dantz, Ch. Genzel and W. ReimersHahn-Meitner-Institut Berlin Glienicker Str. 100, DE-14109 Berlin, Germany E-Mail: dantz@hmi.de D. Dantz, Ch. Genzel and W. ReimersHahn-Meitner-Institut Berlin Glienicker Str. 100, DE-14109 Berlin, Germany E-Mail: dantz@hmi.de  The residual stress state in microwave sintered metal-ceramic functionally graded materials (FGM) consisting of 8Y-ZrO2/Ni and 8Y-ZrO2/NiCr8020, respectively, was analysed by non-destructive diffraction methods. In order to get knowledge of the complete residual stress state in the near surface region as well as in the interior of the material, complementary methods were applied. Whereas the surface was characterised by X-ray techniques using conventional sources, the stresses within the bulk of the material were investigated by means of high energy synchrotron radiation. The stress state was found to obey the differences in the coefficients of thermal expansion (micro-stresses) on the one hand and the inhomogeneous cooling conditions (macrostresses) on the other hand. English Functionally Graded Materials 1998Proceedings of the 5th International symposium on Functionally Graded Materials,held in New Town Hall,Dresden.Germany,october 26-29,1998 Functionally Graded Materials 1998Proceedings of the 5th International symposium on Functionally Graded Materials 6 1998-12-31 837-842 三点曲げ中の積層傾斜機能Ti/TiB光線の破壊テストと解析 Fracture Testing and Analysis of a Layered Functionally Graded Ti/TiB Beam in 3-Point Bending R. D. Carpenter 1, W. W. Liang 2, G. H. Paulino 2, 3, J. C. Gibeling 1 and Z. A. Munir 11 Department of Chemical Engineering and Materials Science, University of California, Davis CA 95616, USA 2 Department of Civil and Environmental Engineering, University of California, Davis CA 95616, USA 3 Graduate Group in Applied Mathematics, University of California, Davis CA 95616, USA R. D. Carpenter 1, W. W. Liang 2, G. H. Paulino 2, 3, J. C. Gibeling 1 and Z. A. Munir 11 Department of Chemical Engineering and Materials Science, University of California, Davis CA 95616, USA 2 Department of Civil and Environmental Engineering, University of California, Davis CA 95616, USA 3 Graduate Group in Applied Mathematics, University of California, Davis CA 95616, USA  This paper presents a methodology for testing and analyzing a layered functionally graded beam consisting of Ti and TiB phases. The test specimen is a single edge notch bending (SENB), with composition varying from a TiB-rich layer at the bottom to commercially pure (CP) Ti at the top. The crack front is aligned parallel to the material gradation and it grows along this direction (mode I). For this crack orientation, "average" R-curve behavior is investigated in order to understand the mechanics of crack growth. The beam is modeled using two-dimensional finite elements considering elastoplastic behavior. Properties of the mixed phase interlayers are approximated using a rule-of-mixtures approach, and the validity of this approach is discussed. Characteristic response quantities are investigated such as the mechanical fields, crack mouth opening displacement, and J integral. English Functionally Graded Materials 1998Proceedings of the 5th International symposium on Functionally Graded Materials,held in New Town Hall,Dresden.Germany,october 26-29,1998 Functionally Graded Materials 1998Proceedings of the 5th International symposium on Functionally Graded Materials 6 1998-12-31 843-848 フライアッシュを用いた傾斜機能材料の作製技術 Productive Techniques of Functionally Graded Materials used of Fly Ash 林 二一 1、 田口広宣 1、 山本孝生 1、渡辺茂男 1、 内田悦行 1、比嘉俊太郎　1、 D. Dykes 21　愛知工業大学　470-0356　愛知県豊田市八草町2　四日市大学　512-8045　三重県四日市市萱生町 N. Hayashi 1, H. Taguchi 1, T. Yamamoto 1, S. Watanabe 1, Y. Uchida 1, S. Higa 1 and D. Dykes 21 Aichi Institute of Technology, Yakusa, Toyota, 4700356, Japan 2 Yokkaichi University, Kayou Yokkaichi 5128045, Japan  This paper presents an attempt to manufacture large-thickness functionally graded materials (FGMs) by means of a solid-liquid separation technique using a vacuum filtration method. The two base materials used ferric oxide and fly ash. English Functionally Graded Materials 1998Proceedings of the 5th International symposium on Functionally Graded Materials,held in New Town Hall,Dresden.Germany,october 26-29,1998 Functionally Graded Materials 1998Proceedings of the 5th International symposium on Functionally Graded Materials 6 1998-12-31 849-854 傾斜組成を伴う延性/脆性結合中の残留応力を探査するためのヴィッカーズ圧痕の使用 Using Vickers Indentation to Probe Residual Stresses in Ductile/Brittle Joints with Graded Compositions I. Reimanis, R. Torres, Ch. Muratore and J. J. MooreMetallurgical and Materials Engineering  Department Colorado School of Mines Golden, Colorado 80401, USA I. Reimanis, R. Torres, Ch. Muratore and J. J. MooreMetallurgical and Materials Engineering  Department Colorado School of Mines Golden, Colorado 80401, USA  Residual stress distributions in metal/ceramic composites with graded compositions are fairly well characterized by theoretical models. However, experimental verification is lacking. Furthermore, it is not well understood how the residual stress distribution affects the composite's response to an applied stress. This paper addresses these issues by discussing numerical predictions of stress distributions, and experimentally examining indentation deformation behavior in two ductile/brittle joints with graded microstructures. NiAl/TiB2 and Cu/W are model systems investigated. It is hypothesized that Vickers indentation can be used to probe the residual stress field in these graded composites, provided the ductile phase has a high enough flow stress, and does not substantially relieve the residual stresses. Finite element models which predict thermal residual stresses in graded materials are compared with experimental measurements and observations, and the implications are discussed. English Functionally Graded Materials 1998Proceedings of the 5th International symposium on Functionally Graded Materials,held in New Town Hall,Dresden.Germany,october 26-29,1998 Functionally Graded Materials 1998Proceedings of the 5th International symposium on Functionally Graded Materials 6 1998-12-31 855-860 対称Al2O3/TiC/Ni　FGMsの内部応力と破壊作用 Internal Stress and Fracture Behaviour of Symmetric Al2O3/TiC/Ni FGMs 林君山、宮本欽生大阪大学　接合科学研究所567-0047大阪府茨木市美穂ケ丘11-1 J. S. Lin and Y. MiyamotoJoining & Welding Research Institute, Osaka University, 11-1, Mihogaoka, Osaka 567-0047, Osaka, Japan  Symmetrically graded Al2O3/TiC/Ni materials were prepared by using SHS/HIP process. A surface compression was introduced by tailoring the thermal mismatch between the outer Al2O3 and the inner TiC/Ni layers. The internal stress before and after the specimen was notched was analyzed by the finite element method. The fracture toughness in the graded structure was determined as a function of the initial notch depth. The results showed that the residual compressive stress can significantly toughen the ceramics, and the toughening effect increased with increasing the notch depth because the residual compressive stress ahead of the notch root increased with increasing the notch depth. This phenomenon resulted in a steep rising R-curve behavior in brittle ceramics. English Functionally Graded Materials 1998Proceedings of the 5th International symposium on Functionally Graded Materials,held in New Town Hall,Dresden.Germany,october 26-29,1998 Functionally Graded Materials 1998Proceedings of the 5th International symposium on Functionally Graded Materials 6 1998-12-31 861-866 傾斜機能材料としての一成分複合材料中の非等方性(異方性)の非-破壊特性評価 Non-Destructive Characterisation of Anisotropy in One-Component Composites as Functionally Graded Materials R. Steegmuller 1, K. Nixdorf 1, K. Stellbrink 2 and G. Busse 11 University Stuttgart, Institute for Polymer Testing and Polymer Science (IKP), Pfaffenwaldring 32, DE-70569 Stuttgart, Germany 2 German Aerospace Center - DLR, Institute for Structures and Design, Pfaffenwaldring 38-40, DE-70569 Stuttgart, Germany R. Steegmuller 1, K. Nixdorf 1, K. Stellbrink 2 and G. Busse 11 University Stuttgart, Institute for Polymer Testing and Polymer Science (IKP), Pfaffenwaldring 32, DE-70569 Stuttgart, Germany 2 German Aerospace Center - DLR, Institute for Structures and Design, Pfaffenwaldring 38-40, DE-70569 Stuttgart, Germany  We investigated a composite-like liquid crystal polymer (LCP) material consisting of only one component where the mechanical properties can be adjusted via the thermal treatment. Due to its high stiffness, strength and especially high energy absorbing capacity, the potential application fields of the material are protective containment components. Non-destructive testing methods are essential to determine, specify, and predict the mechanical behaviour of the material and to monitor the integrity of structures made out of it.      Results are presented for various non-destructive testing methods applicable for characterisation and quality assurance, like ultrasonics, lockin-thermography, and microwave based gradient profiling. English Functionally Graded Materials 1998Proceedings of the 5th International symposium on Functionally Graded Materials,held in New Town Hall,Dresden.Germany,october 26-29,1998 Functionally Graded Materials 1998Proceedings of the 5th International symposium on Functionally Graded Materials 6 1998-12-31 867-872 コンピューター断層装置(CT)による、粉末冶金部分の体積特性の特性評価 Characterization of Volume Properties of Powder Metallurgical Parts by Computerized Tomography J. Goebbels 1, B. Illerhaus 1, G. Weidemann 1 and K. Pischang 21 Bundesanstalt fur Materialforschung und -prufung, Berlin 2 TU Dresden, Institut fur Werkstoffwissenschaft, Dresden J. Goebbels 1, B. Illerhaus 1, G. Weidemann 1 and K. Pischang 21 Bundesanstalt fur Materialforschung und -prufung, Berlin 2 TU Dresden, Institut fur Werkstoffwissenschaft, Dresden  Due to the capability of three-dimensional mapping local density variations computerized tomography (CT) offers excellent non-destructive evaluation possibilities. The measured quantity is the averaged X-ray absorption over a volume element which size depends of the investigated sample and the experimental conditions. The high spatial resolution reached in the last years means that the smallest volume element (Voxel) which can be distinguished from neighbour elements with a different density has an edge length of only 10 μm.       Measurements on model samples and powder metallurgical samples with a continous change in elemental composition are described and the problems connected with the investigation of high density materials. As a first step the results of CT are compared with theoretical calculations to separate from X-ray absorption measurements density variations in the samples from differences in elemental composition. English Functionally Graded Materials 1998Proceedings of the 5th International symposium on Functionally Graded Materials,held in New Town Hall,Dresden.Germany,october 26-29,1998 Functionally Graded Materials 1998Proceedings of the 5th International symposium on Functionally Graded Materials 6 1998-12-31 873-878 位相差を伴う超音波顕微鏡法による、傾斜材料の機械的特性評価 Mechanical Characterisation of Graded Materials by Ultrasonic Microscopy with Phase Contrast J. Ndop, T. J. Kim and W. GrillUniversitat Leipzig, Institut fur Experimentelle Physik II, Linnestr. 5, DE-04103 Leipzig, Germany J. Ndop, T. J. Kim and W. GrillUniversitat Leipzig, Institut fur Experimentelle Physik II, Linnestr. 5, DE-04103 Leipzig, Germany  Surface focused scanning acoustic microscopy with phase contrast in the transmission mode has been employed to determine the mechanical respectively elastic properties of functionally graded materials. Time selective signal acquisition adjusted to the minimum path length in the sample allows the determination of the velocity of acoustic waves averaged over the path of the acoustic beam with a lateral resolution in the vicinity of the wavelength of the ultrasonic waves. Measurements are performed for longitudinal and transversal modes accessible by mode conversion at the interfaces between sample and coupling fluid. This allows the spatially resolved determination of the attenuation, the velocity of ultrasonic waves and the Poisson ratio. From an independent determination of the spatial variation of the density or from the averaged density and adequate modelling the Young's modulus and the shear modulus can also be derived from the data. The method is demonstrated for selected applications concerning functionally graded materials. English Functionally Graded Materials 1998Proceedings of the 5th International symposium on Functionally Graded Materials,held in New Town Hall,Dresden.Germany,october 26-29,1998 Functionally Graded Materials 1998Proceedings of the 5th International symposium on Functionally Graded Materials 6 1998-12-31 879-883 GD-OES(グロ-放電発光分析)を用いた、傾斜コーティングの特性評価 Characterisation of Graded Coatings Using GD-OES D. DelfosseSwiss Federal Laboratories for Materials Testing and Research (EMPA), CH-3602 Thun, Switzerland D. DelfosseSwiss Federal Laboratories for Materials Testing and Research (EMPA), CH-3602 Thun, Switzerland  The GD-OES (Glow Discharge Optical Emission Spectroscopy) is a relatively new tool for the measurement of depth profiles through metallic and ceramic coatings. Depth profiles are recorded across layers ranging in thickness from 10 nm to 100 micrometers. Short measurement times in the order of minutes are characteristic for this method, and it is possible to simultaneously analyse all elements from H to U. The GD-OES is therefore well suited for the analysis of graded coatings as well as gradients introduced by a diffusion mechanism. English Functionally Graded Materials 1998Proceedings of the 5th International symposium on Functionally Graded Materials,held in New Town Hall,Dresden.Germany,october 26-29,1998 Functionally Graded Materials 1998Proceedings of the 5th International symposium on Functionally Graded Materials 6 1998-12-31 884-889 傾斜気孔構造を伴う薄セラミック積層の特性評価 Characterization of Thin Ceramic Layers with a Graded Pore Structure T. Moritz 1, G. Werner 1, G. Tomandl 1, M. Mangler 1, H. Eichler 1, U. Lembke 2 and W. Hauffe 31 Freiberg University of Mining and Technology, Institute of Ceramic Materials, G.-Zeuner-Str. 3, DE-09596 Freiberg, Germany 2 Rostock University, Dept. of Physics, A. -Bebel-Str. 55, DE-18051 Rostock, Germany 3 Technical University Dresden, Institute of Surface Physics and Microstructure Physics, Zellescher Weg 16, DE-O1062 Dresden, Germany T. Moritz 1, G. Werner 1, G. Tomandl 1, M. Mangler 1, H. Eichler 1, U. Lembke 2 and W. Hauffe 31 Freiberg University of Mining and Technology, Institute of Ceramic Materials, G.-Zeuner-Str. 3, DE-09596 Freiberg, Germany 2 Rostock University, Dept. of Physics, A. -Bebel-Str. 55, DE-18051 Rostock, Germany 3 Technical University Dresden, Institute of Surface Physics and Microstructure Physics, Zellescher Weg 16, DE-O1062 Dresden, Germany  Thin ceramic layers with a gradient in the grain size and the pore size distribution were prepared by centrifugal deposition from diluted suspensions with a very low solid content and a multimodal particle size distribution. Besides drying and sintering of the sediments, a main problem is the detection of the gradient which can be expected to appear owing to the settling behaviour of the particles during centrifugation. For this reason, the layers were characterized by quantitative image analysis, atomic force microscopy (AFM) and grazing incidence small angle x-ray scattering (GISAXS). English Functionally Graded Materials 1998Proceedings of the 5th International symposium on Functionally Graded Materials,held in New Town Hall,Dresden.Germany,october 26-29,1998 Functionally Graded Materials 1998Proceedings of the 5th International symposium on Functionally Graded Materials 6 1998-12-31 890-895 走査型熱プローブ(探査子)技術－傾斜半導体および金属の高分解能特性評価のための方法 Scanning Thermo Probe Technique - a Method for High Resolution Characterization of Graded Semiconductors and Metals P. Reinshaus, H. S洫mann, G. Erz, U. Kramer and W. HeiligerMartin-Luther-University Halle-Wittenberg, Department of Physics, Hoher Weg 8, DE-06120 Halle/S.,Germany P. Reinshaus, H. S洫mann, G. Erz, U. Kramer and W. HeiligerMartin-Luther-University Halle-Wittenberg, Department of Physics, Hoher Weg 8, DE-06120 Halle/S.,Germany  The SEEBECK coefficient S of electrical conducting substances is a measure of the carrier concentration and so of the concentration of causing components. With the local resolved measuring of S, this technique turns into a method for determination of concentration distributions. Under specific conditions (one carrier conductivity, known band structure and carrier scattering mechanism) correct quantitative measurement of the SEEBECK-coefficient gives the opportunity of quantitative analysis of the component distribution. This was shown on the example of the analysis of segregationally caused inhomogeneities of non stoichiometric V2VI3 compounds. English Functionally Graded Materials 1998Proceedings of the 5th International symposium on Functionally Graded Materials,held in New Town Hall,Dresden.Germany,october 26-29,1998 Functionally Graded Materials 1998Proceedings of the 5th International symposium on Functionally Graded Materials 6 1998-12-31 896-901 前方および後方表面における温度応答性からの、FGM中の熱拡散率プロフィルの評価 Estimation of Thermal Diffusivity Profile in an FGM from Temperature Responses at the Front and Rear Surfaces 牧野　敦、荒木信幸静岡大学　工学部 機械工学科　432-8561　静岡県浜松市城北3-5-1 A. Makino and N. ArakiDepartment of Mechanical Engineering, Faculty of Engineering, Shizuoka University, Hamamatsu 432-8561, Japan  Temperature response in a functionally graded material (FGM), subjected to transient heating, is investigated in order to estimate thermal diffusivity profile in the FGM, relevant to qualification of FGMs as advanced heat-shielding/structural materials in future space applications. An attempt has been made to use temperature response at the front surface in obtaining a distribution parameter, which gives the thermal diffusivity profile in FGM when a distribution of the thermal diffusivity can be expressed by an exponential function. Following a procedure in the literature, an explicit relation is obtained between the distribution parameter and thermal diffusivity at the front surface. Although it is approximate, it has turned out to be a fair representation for the dependence of the temperature response on the thermal diffusivity. In order to further examine usefulness of this relation, a comparisons has been made between the assumed and estimated thermal diffusivity profiles. In this examination, a distribution parameter near the front surface is determined by the thermal diffusivity at the front surface; that near the rear surface is determined by the thermal diffusivity at the rear surface. A fair agreement between these profiles is demonstrated, as far as the trend and approximate magnitude are concerned. English Functionally Graded Materials 1998Proceedings of the 5th International symposium on Functionally Graded Materials,held in New Town Hall,Dresden.Germany,october 26-29,1998 Functionally Graded Materials 1998Proceedings of the 5th International symposium on Functionally Graded Materials 6 1998-12-31 902-907 SiC組成傾斜炭素繊維-補強炭素複合材料の酸化と熱衝撃抵抗 Oxidation and Thermal Shock Resistance of SiC Compositionally Graded Carbon Fiber-Reinforced Carbon Composite Materials 山田禮司、藤井貴美夫日本原子力研究所　材料研究部　319-1195茨城県那珂郡東海村白方白根２－４ R. Yamada and K. FujiiDepartment of Materials Science and Engineering, Japan Atomic Energy Research Institute, Tokai-mura, Ibaraki-ken 319-1195, Japan  SiC compositionally graded carbon fiber-reinforced carbon composite (CFC) materials, which were composed of CVD SiC, SiC/CFC layer and CFC substrate, were fabricated, and their oxidation and thermal shock resistance were studied by weight loss method. It was found that both CVD SiC and SiC/CFC layer were effective to increase the oxidation resistance, and so did the SiC/C layer to the thermal shock resistance. The oxidation resistance of CFCs with CVD SiC increased with increasing the ratio of thermal expansion coefficient (CTE) of substrate to that of CVD SiC, and the effect of SiC/CFC layer on improvement of thermal shock resistance became maximum when the difference in CTE was minimal. It was also observed that the direction of surface cracks in CVD SiC was mostly normal to the direction of the smallest CTE on each substrate. These results can be explained in terms of tensile or compressive stresses in CVD SiC at a cooling period of a thermal shock test or that of fabrication. English Functionally Graded Materials 1998Proceedings of the 5th International symposium on Functionally Graded Materials,held in New Town Hall,Dresden.Germany,october 26-29,1998 Functionally Graded Materials 1998Proceedings of the 5th International symposium on Functionally Graded Materials 6 1998-12-31 908-911 炭素‐複合材料吸着剤の表面不均一性の特性評価 Characterization of Surface Heterogeneity of Carbon-Composite Adsorbents A. M. Puziy and O. I. PoddubnayaInstitute for Sorption and Problems of Endoecology, Naumov st. 13, UA-252164 Kyiv, Ukraine A. M. Puziy and O. I. PoddubnayaInstitute for Sorption and Problems of Endoecology, Naumov st. 13, UA-252164 Kyiv, Ukraine  Surface functionality of carbon-composite adsorbents were characterised in terms of proton affinity distribution using potentiometric titration method and numerically stable algorithm CONTIN. Surface groups beyond the experimentally measured range of pH was accounted for by constant background term. Modification of carbon with titanium and silicon oxides increases 2.5 times the total amount of ion exchange sites and creates new groups mostly with pK=5.8 and 8.3. Synthetic carbons modified with phosphorus compounds possess acidic character like oxidised carbons and shows 3 types of surface groups. In addition, such carbons possess considerable amount of "super" acidic groups with pK<2. Oxidation with nitric acid creates mostly acidic (pK=3.6) and phenolic (pK=10.6) groups. Due to very acidic character phosphorus-containing carbons may be regarded as prospective cation exchangers for removal of heavy metals from water solutions. English Functionally Graded Materials 1998Proceedings of the 5th International symposium on Functionally Graded Materials,held in New Town Hall,Dresden.Germany,october 26-29,1998 Functionally Graded Materials 1998Proceedings of the 5th International symposium on Functionally Graded Materials 6 1998-12-31 917-922 FGMコーティングの剥離に関して On the Spallation of FGM Coatings F. Erdogan and T. -C. ChiuDepartment of Mechanical Engineering and Mechanics Lehigh University, Bethlehem, PA 18015, USA F. Erdogan and T. -C. ChiuDepartment of Mechanical Engineering and Mechanics Lehigh University, Bethlehem, PA 18015, USA  In this study the problem of FGM coatings with an interface crack subjected to a mechanically or thermally induced compressive load parallel to the free surface is considered. First by using a nonlinear continuum theory the problem is reduced to an eigenvalue problem and the buckling instability load is evaluated analytically. The postbuckling problem is then examined numerically. The strain energy release rate and the stress intensity factors are directly calculated from special enriched crack tip elements. English Functionally Graded Materials 1998Proceedings of the 5th International symposium on Functionally Graded Materials,held in New Town Hall,Dresden.Germany,october 26-29,1998 Functionally Graded Materials 1998Proceedings of the 5th International symposium on Functionally Graded Materials 6 1998-12-31 923-929 傾斜機能Ti-TiC多層：基質への接合に対する傾斜プロフィルの効果 Functionally Graded Ti-TiC Multilayers: The Effect of a Graded Profile on Adhesion to Substrate I. Dahan, U. Admon, J. Sariel, B. Yahav, M. Amar, N. Frage and M. P. DarielDepartment of Materials Engineering, Ben-Gurion University of the Negev, Beer-Sheva, Israel I. Dahan, U. Admon, J. Sariel, B. Yahav, M. Amar, N. Frage and M. P. DarielDepartment of Materials Engineering, Ben-Gurion University of the Negev, Beer-Sheva, Israel  Thin Ti-TiC multilayer coatings on silicon substrates, when sputtered under bias, are in a state of compressive stress due to the incorporation of argon into the deposited layer. Under certain conditions, the compressive stresses lead to spontaneous delamination of the coating. The delamination process takes place by the propagation of a front of concentrated stress that produces local interface separation. The delamination process is characterized by outward buckling of the coating that propagates with relatively well-defined wavelengths of the order of 30 to 70 nm. Ultimately the delamination grows into a complex wrinkling pattern of the coating.       The Ti-TiC graded multilayers were deposited with pre-designed composition profiles that affect the state of stress within the coating. The profile reflects the variation of the TiC/Ti ratio along the z-direction, perpendicular to the coating. Elementary composition profiles are characterized by one single parameter, k , that defines whether the TiC/Ti ratio is concave (for k<1) or convex (k>1) with respect to z. Graded multilayers with different values of k display delamination patterns that vary both by their kinetics and by the final morphology of the coating. In particular, graded multilayers with k>=3, display long term stability. The results illustrate the potential of graded coatings to reduce intrinsic stresses leading to delamination and failure. English Functionally Graded Materials 1998Proceedings of the 5th International symposium on Functionally Graded Materials,held in New Town Hall,Dresden.Germany,october 26-29,1998 Functionally Graded Materials 1998Proceedings of the 5th International symposium on Functionally Graded Materials 6 1998-12-31 930-935 傾斜セラミックコーティング中の熱残留応力のモデリング Modelling of Thermal Residual Stresses in Graded Ceramic Coatings V. Teixeira 1, M. Andritschky 1 and D. Stover 21 University of Minho-Department of Physics, IMAT - Institute of Materials, Campus de Gualtar, PT-4700 Braga, Portugal E-Mail: vasco@fisica. uminho.pt 2 Forschungszentrum Julich GmbH IWE 2-Institute for Materials in Energy Systems, DE-52425 Julich, Germany V. Teixeira 1, M. Andritschky 1 and D. Stover 21 University of Minho-Department of Physics, IMAT - Institute of Materials, Campus de Gualtar, PT-4700 Braga, Portugal E-Mail: vasco@fisica. uminho.pt 2 Forschungszentrum Julich GmbH IWE 2-Institute for Materials in Energy Systems, DE-52425 Julich, Germany  In this contribution we present a numerical calculation of thermal residual stress distribution within a multilayered system which consists of a Functionally Gradient Material (FGM). The structure of the graded system is made of a ceramic layer and a metallic layer, where between them there is an interlayer which is a graded composite made of the metal (NiCr alloy) and the ceramic (Al2O3 and stabilised ZrO2). For numerical modelling of this graded interlayer, an approximation was done as a series of perfectly bonded finite layers, each having slightly different material properties. We analyse the FGM design in respect to thermal stress optimisation. The effects on residual stress distribution of the compositional profiles and graded interlayer thickness were studied for the case of a bilayer structure and a graded thermal barrier coating (TBC). English Functionally Graded Materials 1998Proceedings of the 5th International symposium on Functionally Graded Materials,held in New Town Hall,Dresden.Germany,october 26-29,1998 Functionally Graded Materials 1998Proceedings of the 5th International symposium on Functionally Graded Materials 6 1998-12-31 936-941 薄傾斜Al2O3/ZrO2 TBCシステム中の応力解析 Stress Analysis in Thin Graded Al2O3/ZrO2 TBC Systems U. Leushake 1, Y. Y. Yang 2 and W. Schaller 21 DLR - German Aerospace Center, Institute of Materials Research, Cologne, Germany 2 Research Center Karlsruhe, Institute for Materials Research, Karlsruhe, Germany U. Leushake 1, Y. Y. Yang 2 and W. Schaller 21 DLR - German Aerospace Center, Institute of Materials Research, Cologne, Germany 2 Research Center Karlsruhe, Institute for Materials Research, Karlsruhe, Germany  Graded alumina/zirconia thermal barrier coatings (TBCs) offer a great potential for improved TBC performance. This paper describes the effects of a graded interlayer within a TBC system in comparison to a standard TBC system for two different load cases, homogeneous temperature change as well as application in a temperature gradient. The modification of stress distribution and maximum stresses is analyzed. The strain energy release is used as an additional design criteria.       Analyzing the application in a temperature gradient the different thermal conductivities of alumina and zirconia have to be taken into account in order to keep the heat flux through the coating constant for all considered systems. Same heat flux conditions can be achieved by adjusting the overall coating thickness based on the normalized effective thermal resistivity R*. English Functionally Graded Materials 1998Proceedings of the 5th International symposium on Functionally Graded Materials,held in New Town Hall,Dresden.Germany,october 26-29,1998 Functionally Graded Materials 1998Proceedings of the 5th International symposium on Functionally Graded Materials 6 1998-12-31 942-947 傾斜機能材料を伴う応用における応力最適化 Stress Optimization in Applications with Functionally Graded Materials W. Schaller and Y. Y. YangInstitute for Materials Research, Forschungszentrum Karlsruhe, P. O. Box 3640, DE-76021 Karlsruhe, Germany W. Schaller and Y. Y. YangInstitute for Materials Research, Forschungszentrum Karlsruhe, P. O. Box 3640, DE-76021 Karlsruhe, Germany  For multi-layer joints in functionally graded materials (FGM) optimized transition functions were determined. The optimization criteria were thermal stresses in the joint. The methods used for determining the optimized transition functions were the gradient algorithm and the swarm search algorithm. English Functionally Graded Materials 1998Proceedings of the 5th International symposium on Functionally Graded Materials,held in New Town Hall,Dresden.Germany,october 26-29,1998 Functionally Graded Materials 1998Proceedings of the 5th International symposium on Functionally Graded Materials 6 1998-12-31 948-953 材料クリープ作用を考慮しての、傾斜機能材料を伴う結合中の応力解析 Stress Analysis in a Joint with Functionally Graded Materials Considering Material Creep Behavior Y. Y. YangInstitute for Materials Research, Forschungszentrum Karlsruhe, P. O. Box 3640, DE-76021 Karlsruhe, Germany Y. Y. YangInstitute for Materials Research, Forschungszentrum Karlsruhe, P. O. Box 3640, DE-76021 Karlsruhe, Germany  In this paper, a joined cylinder with a functionally graded material (FGM) is considered. The analytical solution to calculate stresses in FGM is presented considering the creep behavior of the materials, which can be used to study the time and temperature dependence of the stresses. The results of the stress distribution in FGM are shown in some examples. English Functionally Graded Materials 1998Proceedings of the 5th International symposium on Functionally Graded Materials,held in New Town Hall,Dresden.Germany,october 26-29,1998 Functionally Graded Materials 1998Proceedings of the 5th International symposium on Functionally Graded Materials 6 1998-12-31 957-962 傾斜機能材料の脆性破壊のための統計的RKR破壊モデル A Statistical RKR Fracture Model for the Brittle Fracture of Functionally Graded Materials T. L. Becker, Jr., R. M. Cannon and R. O. RitchieUniversity of California at Berkeley and Materials Sciences Division, 1 Cyclotron Rd, MS 62-203, Lawrence Berkeley National Laboratory, Berkeley, CA 94720-1760 USA T. L. Becker, Jr., R. M. Cannon and R. O. RitchieUniversity of California at Berkeley and Materials Sciences Division, 1 Cyclotron Rd, MS 62-203, Lawrence Berkeley National Laboratory, Berkeley, CA 94720-1760 USA  A statistical Ritchie-Knott-Rice (RKR) [1] model for brittle fracture is considered for an FGM containing a slender notch. The FMG is modeled as linear elastic, with its strength described by two-parameter Weibull statistics. The Young's modulus is assumed to vary either linearly or sigmoidally. A compact tension (C(T)) fracture mechanics specimen is analyzed via the finite element method, considering the effect of modulus variation on the near-tip stress state. Results can be characterized by the stress intensity, K. For spatially constant Weibull parameters, the RKR model is used to predict the expected fracture toughness, K(phi), i. e., the K at which the first flaw failure occurs with probability (phi). For sufficiently high Weibull modulus, the failure occurs essentially at the notch tip. For sufficiently low Weibull modulus (m < 4), K(phi) for an FGM is found to vary up to 25% from that of a homogeneous body. English Functionally Graded Materials 1998Proceedings of the 5th International symposium on Functionally Graded Materials,held in New Town Hall,Dresden.Germany,october 26-29,1998 Functionally Graded Materials 1998Proceedings of the 5th International symposium on Functionally Graded Materials 6 1998-12-31 963-970 FGMs中の破壊耐性への、降伏強度勾配の影響 The Influence of the Yield Strength Gradient on the Fracture Resistance in FGMs O. Kolednik 1, 2 and S. Suresh 11 Department for Materials Science and Engineering, Massachusetts Avenue, Cambridge, MA 02139, USA 2 On leave from the Erich Schmid Institute of Materials Science, Austrian Academy of Sciences, Jahnstraァe 12, AU-8700 Leoben, Austria O. Kolednik 1, 2 and S. Suresh 11 Department for Materials Science and Engineering, Massachusetts Avenue, Cambridge, MA 02139, USA 2 On leave from the Erich Schmid Institute of Materials Science, Austrian Academy of Sciences, Jahnstraァe 12, AU-8700 Leoben, Austria  In materials with local changes in yield strength, the near-tip crack driving force becomes different from the applied far-field value. This effect is termed here as the plasticity gradient effect. A model is developed that allows us to derive analytical expressions to quantify the plasticity gradient effect for smooth and abrupt variations in yield strength. The predictions of the model agree well with previous finite element computations and available experimental observations. The model can be used to optimize the fracture properties of FGMs, as well as interface and interlayer transitions. English Functionally Graded Materials 1998Proceedings of the 5th International symposium on Functionally Graded Materials,held in New Town Hall,Dresden.Germany,october 26-29,1998 Functionally Graded Materials 1998Proceedings of the 5th International symposium on Functionally Graded Materials 6 1998-12-31 971-976 傾斜機能材料中のモードIII亀裂のための傾斜弾性理論 Gradient Elasticity Theory for a Mode III Crack in a Functionally Graded Material G. H. Paulino 1, A. C. Fannjiang 2 and Y. -S. Chan 21 Department of Civil & Environmental Engineering, and Graduate Group in Applied Mathematics (GGAM) University of California, Davis, CA 95616, USA 2 Department of Mathematics, University of California, Davis, CA 95616, USA G. H. Paulino 1, A. C. Fannjiang 2 and Y. -S. Chan 21 Department of Civil & Environmental Engineering, and Graduate Group in Applied Mathematics (GGAM) University of California, Davis, CA 95616, USA 2 Department of Mathematics, University of California, Davis, CA 95616, USA  Anisotropic strain gradient elasticity theory is applied to the solution of a mode III crack in a functionally graded material (FGM). The theory includes both volumetric and surface energy terms, and a particular form of the moduli variation. The crack boundary value problem is solved by means of Fourier transform and a hypersingular integral equation of the Fredholm type. The solution naturally leads to a cusping crack, which is consistent with Barenblatt's "cohesive zone" theory, but without the assumption regarding existence of interatomic forces. The numerical implementation is discussed and examples are given, which provide insight into the cracking phenomenon in FGMs governed by strain gradient elasticity with characteristic lengths associated to volumetric and surface strain energy terms. English Functionally Graded Materials 1998Proceedings of the 5th International symposium on Functionally Graded Materials,held in New Town Hall,Dresden.Germany,october 26-29,1998 Functionally Graded Materials 1998Proceedings of the 5th International symposium on Functionally Graded Materials 6 1998-12-31 977-982 FGMの変形作用のモデリング Modelling of the Deformation Behaviour of FGM S. Raァbach and W. LehnertFreiberg University of Mining and Technology, Institute of Metal Forming, Bernhard-von-Cotta-Str. 4, DE-09596 Freiberg, Germany S. Raァbach and W. LehnertFreiberg University of Mining and Technology, Institute of Metal Forming, Bernhard-von-Cotta-Str. 4, DE-09596 Freiberg, Germany  A lot of processes for the manufacture of functionally gradient materials (FGM) have their limitations (simple geometry of components, gradient limited in one direction, etc.). A further treatment by forming processes would extend the field of applications of FGM because it would make it possible to manufacture shaped pieces and to influence the properties of the material. For this it is necessary to predetermine the deformation behaviour by mathematical models. Conventional equations have only limited application because many other influences have to be considered. Therefore, a new model based on mathematical methods of Fuzzy Logic has been developed which can describe the plasto-mechanical behaviour of FGM during the deformation process. Experiments to determine the deformation behaviour have been carried out on different material systems (Al/Cu, 316L/430L, Al/SiC) by using the hot upsetting test. The results show that this kind of modelling is suitable to describe the deformation behaviour very accurately. The model data should be applied for the simulation of the deformation behaviour of FGM component parts by the finite element method. English Functionally Graded Materials 1998Proceedings of the 5th International symposium on Functionally Graded Materials,held in New Town Hall,Dresden.Germany,october 26-29,1998 Functionally Graded Materials 1998Proceedings of the 5th International symposium on Functionally Graded Materials 6 1998-12-31 983-988 熱-機械的負荷の下での傾斜機能材料のデザインのためのシミュレーションモデル A Simulation Model for the Design of Functionally Graded Materials under Thermo-Mechanical Loads W. Hufenbach, G. Archodoulakis and M. LepperInstitut fur Leichtbau und Kunststofftechnik der Technischen Universitat Dresden, DE-O1062 Dresden, Germany W. Hufenbach, G. Archodoulakis and M. LepperInstitut fur Leichtbau und Kunststofftechnik der Technischen Universitat Dresden, DE-O1062 Dresden, Germany  High-performance multi-layered Functionally Graded Materials (FGMs) have a wide range of structural applications, such as modern engine and turbine technologies. However, in most technical applications the difference between the FGM layers' thermal expansion coefficients and Young's moduli induces stress and strain fields during operation. These stresses and strains can result in failure of the FGM if, for example, the tensile strength of a brittle partner is exceeded.       In optimizing composite structures with respect to material compatibility, the objective is to achieve an FGM design which minimizes failure stresses in the layers. High-performance composites of this kind permit a wide variety of applications beyond the range of the individual materials.       For the design of FGMs under thermo-mechanical loads, a simulation model on the basis of analytical solutions is presented. This model allows - in contrast to the Finite Element Method - a quick and efficient variation of material parameters, such as the thermal expansion coefficient and Young's modulus, as well as the optimization of thickness ratios. For the example of a thermo-mechanically loaded FGM plate, a variation of material and geometrical parameters is performed. English Functionally Graded Materials 1998Proceedings of the 5th International symposium on Functionally Graded Materials,held in New Town Hall,Dresden.Germany,october 26-29,1998 Functionally Graded Materials 1998Proceedings of the 5th International symposium on Functionally Graded Materials 6 1998-12-31 989-994 最適FGMs、そしてプレインオウフル複合材料 Optimal FGMs, and Plain Awful Composites M. Ferrari 1, F. Rooney 1 and J. C. Nadeau 21 Biomedical Microdevices Center, Dept. of Civil and Environmental Engineering, Dept. of Materials Science and Mineral Engineering, University of California, Berkeley, CA 94720-1710, USA 2 Dept. of Civil and Environmental Engineering, Duke University, Durham, NC 27708-0287, USA M. Ferrari 1, F. Rooney 1 and J. C. Nadeau 21 Biomedical Microdevices Center, Dept. of Civil and Environmental Engineering, Dept. of Materials Science and Mineral Engineering, University of California, Berkeley, CA 94720-1710, USA 2 Dept. of Civil and Environmental Engineering, Duke University, Durham, NC 27708-0287, USA  The worst possible mechanical performance of a composite material of given composition is attained for a homogeneous distribution of the second phase. This conclusion is reached upon analyzing the St. Venant problem (extension, torsion, bending, flexure) for a wide class of FGMs in this communication. With opportunities for optimization in full view, the problem of FGM optimization is then addressed, in the context. of the thermoelastic response of bi-phase, anisotropic layers. English Functionally Graded Materials 1998Proceedings of the 5th International symposium on Functionally Graded Materials,held in New Town Hall,Dresden.Germany,october 26-29,1998 Functionally Graded Materials 1998Proceedings of the 5th International symposium on Functionally Graded Materials 6 1998-12-31 995-999 傾斜機能材料の有効特性のためのランダム微細構造有限要素法 A Random Microstructure Finite Element Method for Effective Properties of Functionally Graded Materials P. -C. Zhai, Q. -J. Zhang and R. -Z. YuanState Key Laboratory of Materials Synthesis and Processing, Wuhan University of Technology, Wuhan 430070, China P. -C. Zhai, Q. -J. Zhang and R. -Z. YuanState Key Laboratory of Materials Synthesis and Processing, Wuhan University of Technology, Wuhan 430070, China  A random microstructure finite element method for effective properties of functionally graded materials is developed. The method combines a random mathematical model and a computer automatically geometry formation technique with finite element analysis. The random microstructure either in a dispersive form or in an interwoven form can exactly be described. The interaction of the inclusion-inclusion and of the inclusion-matrix as well as the influence of boundary conditions in the microstructure can accurately be treated. The method is verified by two examples and proved to be very effective in predicting macro properties of the materials, especially when the microstructure contains randomly distributed cracks. English Functionally Graded Materials 1998Proceedings of the 5th International symposium on Functionally Graded Materials,held in New Town Hall,Dresden.Germany,october 26-29,1998 Functionally Graded Materials 1998Proceedings of the 5th International symposium on Functionally Graded Materials 6 1998-12-31 1000-1005 微少機構マトリシティーモデルに基づく相互貫入微細構造に関連したFGMを含有する複合材料の中機構モデリング Mesomechanical Modelling of Composites Containing FGM Related Interpenetrating Microstructures Based on Micromechanical Matricity Models M. Dong, P. Leァle, U. Weber and S. SchmauderStaatliche Materialprufungsanstalt (MPA) University of Stuttgart, Pfaffenwaldring 32, DE-70569 Stuttgart, Germany M. Dong, P. Leァle, U. Weber and S. SchmauderStaatliche Materialprufungsanstalt (MPA) University of Stuttgart, Pfaffenwaldring 32, DE-70569 Stuttgart, Germany  A self-consistent micromechanical matricity model was recently developed to simulate the mechanical behaviour of an isotropic two-phase composite with a coarse interpenetrating microstructure. The model is an extension of a self-consistent model for matrices with randomly distributed inclusions. In addition to the volume fraction of the phases, the matricity model allows a further parameter of the microstructure to be included into the simulation of the mechanical behaviour of composites with interpenetrating microstructures. The matricity of each phase can be determined from a representative micrograph of a two-phase material. The model was earlier applied to calculate the mechanical behaviour of different graded materials, such as metal-ceramic (ZrO2/NiCr 80 20) and metal-metal composites. In this paper the mechanical behaviour of W/Cu composites is simulated. The micromechanical model allows to predict the thermo-elastic and plastic behaviour of two phase composites and requires the phase properties, phase arrangement and volume fraction as input parameters. Good agreement is found with experimental data such as elastic modulus and thermal expansion coefficient. Moreover, residual stresses are found to influence the elastic behaviour, if the soft phase (copper) dominates by volume fraction and phase arrangement. The results are used to elaborate the influence of phase arrangements and can be used to predict the mechanical performance of FGMs. English Functionally Graded Materials 1998Proceedings of the 5th International symposium on Functionally Graded Materials,held in New Town Hall,Dresden.Germany,october 26-29,1998 Functionally Graded Materials 1998Proceedings of the 5th International symposium on Functionally Graded Materials 6 1998-12-31 1006-1011 遺伝アルゴリズムによる、FGM組成分布プロフィルデザインの最適化方法 Optimization Method of FGM Compositional Distribution Profile Design by Genetic Algorithm 下島康嗣１、山田康雄１、馬渕守１、斎藤尚文１、中西勝１、重松一典１、中村守１、朝比奈正１、五十嵐　廉２１　名古屋工業技術研究所　462-8510愛知県名古屋市北区平手町１丁目１番地２　東京タングステン株式会社　931-8543富山県富山市岩瀬古志町２ K. Shimojima 1, Y. Yamada 1, M. Mabuchi 1, N. Saito 1, M. Nakanishi 1, I. Shigematsu 1, M. Nakamura 1, T. Asahina 1 and T. Igarashi 21 National Industrial Research Institute of Nagoya, Hirate-cho, Kita-ku, Nagoya 462-8510, Japan 2 Tokyo Tungsten Co. Ltd., Iwasekoshi-machi, Toyama 931-8543, Japan  The progress of technologies requires high performance materials. However it is sometimes difficult to achieve the required high performance by homogeneous material . Therefore composite materials have been developed so far. Functionally graded materials (FGM), which is a kind of composite materials, can change the material property in each area for its objective such as heat transfer property, stiffness, and so on, by controlling a compositional distribution ratio of materials. Therefore we can make a product which has two or more different desirable properties in one body. However it is difficult to design a compositional distribution ratio of an FGM as a desired one, because material properties of one part relates to the other part and its shapes and surroundings also affect the properties. In this paper, we propose the automatic compositional distribution profile design system for FGM. The proposed system optimizes the compositional distribution profile to satisfy requirements. The design system consists of two parts: Analyzer and Optimizer. We employ the Finite Element Method as Analyzer for analysis of the state of the product and Genetic Algorithms as Optimizer for optimization of the compositional distribution profile. To show the effectiveness of the proposed design system, we apply the proposed system to thermal stress relaxation problem. English Functionally Graded Materials 1998Proceedings of the 5th International symposium on Functionally Graded Materials,held in New Town Hall,Dresden.Germany,october 26-29,1998 Functionally Graded Materials 1998Proceedings of the 5th International symposium on Functionally Graded Materials 6 1998-12-31 1012-1017 WC-素地硬金属構造モデリング：構造側面の解釈のためのガイドライン WC-Based Hardmetal Structural Modelling: Guidelines for the Interpretation of Structural Aspects U. U. Gomes, A. C. Buriti and A. G. P. da SilvaDepartamento de Fisica, Universidade Federal do Rio Grande do Norte, 59072-970, Natal, RN, Brazil U. U. Gomes, A. C. Buriti and A. G. P. da SilvaDepartamento de Fisica, Universidade Federal do Rio Grande do Norte, 59072-970, Natal, RN, Brazil  WC-based hard metal structures are commonly characterized by metallographic observation. Parameters such as WC intercept length and Co chord are used to give information about the WC granulation and Co distribution. In order to establish correspondence between the 2-Dimensional structural aspects observed in the metallographic technique and the 3-Dimensional aspects of the real structure, computer simulation is carried out by modelling totally controlled 3-D WC granulation and observing the correspondent 2-D aspects as measured by the metallography. This simulation allows the building up of the structural aspects as seen by the metallographic measurements step by step, making possible a better understanding of the actual 3-D hard metal structure. English Functionally Graded Materials 1998Proceedings of the 5th International symposium on Functionally Graded Materials,held in New Town Hall,Dresden.Germany,october 26-29,1998 Functionally Graded Materials 1998Proceedings of the 5th International symposium on Functionally Graded Materials 6 1998-12-31 1018-1023 傾斜CuW材料の残留応力状態 Residual Stress States of Graded CuW Materials G. Bokuchava 2, J. Schreiber 1, N. Shamsutdinov 2 and M. Stalder 11 Fraunhofer - Institute for Non-Destructive Testing, EADQ Dresden, Krugerstraァe 22, Germany 2 Joint Institute for Nuclear Research, FLNP Dubna, Russia G. Bokuchava 2, J. Schreiber 1, N. Shamsutdinov 2 and M. Stalder 11 Fraunhofer - Institute for Non-Destructive Testing, EADQ Dresden, Krugerstraァe 22, Germany 2 Joint Institute for Nuclear Research, FLNP Dubna, Russia  The residual stress states of different W-Cu gradient samples were analysed by neutron diffraction. It was found that plastic deformation can strongly modify the thermally induced stresses. The thermal expansion coefficients of the individual phases within the composite were determined indicating that the two sublattices influence each other. Uniaxial compressional loading carried out to investigate the mechanical properties of the composites imply that the yield strength for copper increases to up to 300 MPa in a 20Cu/80W vol. % sample. Finally, the influence of the manufacturing process on the stress state was checked by repeating the stress analysis with one of the samples after annealing. English Functionally Graded Materials 1998Proceedings of the 5th International symposium on Functionally Graded Materials,held in New Town Hall,Dresden.Germany,october 26-29,1998 Functionally Graded Materials 1998Proceedings of the 5th International symposium on Functionally Graded Materials 6 1998-12-31 1024-1029 FEM(有限要素法)による、ダイアモンド段階的-分散材料のデザイン Design of Diamond Gradually - Dispersed Material by FEM 辻上哲也１、大柳満之１、小泉光恵２、A. Levashov 3 I. P. Borovinskaya ４１龍谷大学　ハイテクリサーチセンター２龍谷大学　龍谷エクステンションセンター3 Moscow Steel and Alloys Institute, Russia 4 Institute of Structural Macrokinetic Academy of Science, Russia T. Tsujikami 1, M. Ohyanagi 1, M. Koizumi 2, E. A. Levashov 3 and I. P. Borovinskaya1 High-tech Research Center, Ryukoku University, Japan 2 REC, Ryukoku University, Japan 3 Moscow Steel and Alloys Institute, Russia 4 Institute of Structural Macrokinetic Academy of Science, Russia  Diamond gradually-dispersed material is fabricated by the SHS (Self-propagating High-temperature Synthesis) method as a heat-resistant material. In a system of two layers composed of diamond dispersed and matrix layers, however, high residual stress must be generated in the interface. Therefore, gradually-dispersion of diamond in the matrix reaction is required to reduce the residual stress. In this study, the finite element method has been developed to evaluate macroscopic and microscopic stresses for the design of the diamond gradually-dispersed materials. The developed program for macroscopic analysis can treat an axi-symmetric specimens, allowing two dimensional models. The example model system composed Diamond/(TiB2/Si) and TiB2/Si layer. In this simulation, thermal residual stress, considering only elastic behavior, was calculated. The residual stress is relaxed in a three layers system compared with the two layers system. In the three layers system, an effect of the number of laminas in the middle layer (division of the middle layer) on the residual stress between the matrix layer and the neighbor layer with least diamond concentration was evaluated. The division of middle layer tend to reduce the residual stress effectively up to about ten laminas in the middle layer, but there was almost no farther effect with more than about ten laminas. We also have been developed an image mesh generation system to make the mesh model of microscopic structure, and carried out a microscopic analysis for diamond dispersed material by using the homogenization method. It is recognized that the developed system is able to apply to evaluate the stress of microscopic structure for particle dispersed materials. English Functionally Graded Materials 1998Proceedings of the 5th International symposium on Functionally Graded Materials,held in New Town Hall,Dresden.Germany,october 26-29,1998 Functionally Graded Materials 1998Proceedings of the 5th International symposium on Functionally Graded Materials 6 1998-12-31 1030-1034 セラミック-金属傾斜機能材料の熱破損-熱伝導共役モデル A Thermal Damage-Heat Conduction Coupled Model of Ceramic-Metal Functionally Graded Materials Q. -J. Zhang, P. -C. Zhai and R. -Z. YuanState Key Laboratory of Materials Synthesis and Processing, Wuhan University of Technology, Wuhan 430070, China Q. -J. Zhang, P. -C. Zhai and R. -Z. YuanState Key Laboratory of Materials Synthesis and Processing, Wuhan University of Technology, Wuhan 430070, China  The coupling/interaction between the thermal damage and heat conduction of ceramic-metal FGMs under thermal shock and cyclic thermal loading is an important phenomenon. A theoretical model on the coupling phenomenon is developed to examine, quantitatively, the relationship between the thermal shock damage and effective thermal conductivity. The model is investigated with an effective medium method characterized by a self-consistent micromechanics. The thermal damage is treated as randomly distributed, penny-shaped microcracks. The damage effect is accounted for by introducing a crack density parameter. The effective thermal conductivity of the FGM interlayers is derived in terms of the model and connected with the crack density parameter. The model is verified by a concrete example and provides a new, useful method for the thermal damage evaluation of the materials. English Functionally Graded Materials 1998Proceedings of the 5th International symposium on Functionally Graded Materials,held in New Town Hall,Dresden.Germany,october 26-29,1998 Functionally Graded Materials 1998Proceedings of the 5th International symposium on Functionally Graded Materials 6 1998-12-31 1035-1040 焼結の間の、傾斜組成物質の歪みと亀裂 Distortions and Cracking of Graded Components During Sintering H. Riedel and T. KraftFraunhofer-Institut fur Werkstoffmechanik, Wohlerstr. 11, DE-79108 Freiburg, Germany H. Riedel and T. KraftFraunhofer-Institut fur Werkstoffmechanik, Wohlerstr. 11, DE-79108 Freiburg, Germany  The aim of the project is to develop methods for predicting distortions and cracking during the fabrication of gradient materials, and to apply them to simple geometries (tubes, beams and plates). Crack formation during sintering is described as the instability of the homogeneous sintering state. It is found that a density disturbance may grow unstably, but only when the material is severly constrained in three dimensions.       The equations for describing the distortions of graded beams and plates during sintering are developed. Examples are shown for plates with gradients in grain size, temperature and composition (Mo and ZrO2). If the gradient is carefully balanced, nearly planar plates can be obtained after sintering. Three-dimensional finite element studies of graded circular plates show that the initially axisymmetric mode of deformation becomes unstable in favor of a warping with two symmetry planes (like a potato chip). English Functionally Graded Materials 1998Proceedings of the 5th International symposium on Functionally Graded Materials,held in New Town Hall,Dresden.Germany,october 26-29,1998 Functionally Graded Materials 1998Proceedings of the 5th International symposium on Functionally Graded Materials 6 1998-12-31 1041-1046 混合粉末成形体の焼結のための構造モデル A Constitutive Model for Sintering of Mixed Powder Compacts 品川一成 1、平島康2１　阿南工業高等専門学校　774-0017徳島県阿南市見能林町２　徳島県立工業技術センター　770-8021徳島県徳島市雑賀町 K. Shinagawa 1 and Y. Hirashima 21 Anan College of Technology, Minobayashi, Anan, Tokushima 774-0017, Japan 2 Tokushima Prefectural Industrial Technology Center, Saiga, Tokushima 770-8021, Japan  Variations in the sintering rate of metal/ceramic powder mixtures are examined. Alumina and stainless steel powders are mixed in different ratios with a binder and compacted by CIPing and fired. The change in microstructure and the shrinkage of the specimens are examined. The effects of mixing ratio, difference in powder size and pore size distribution on the densification are discussed. The shrinkage behavior of the mixed powders is modelled using a constitutive equation for sintering of each component powder. The interaction between a metal and a ceramic powder region is taken into consideration to the model. The model provides a good fit of the experimental data. English Functionally Graded Materials 1998Proceedings of the 5th International symposium on Functionally Graded Materials,held in New Town Hall,Dresden.Germany,october 26-29,1998 Functionally Graded Materials 1998Proceedings of the 5th International symposium on Functionally Graded Materials 6 1998-12-31 1047-1052 粒子FGMの焼結下での破損蓄積のモデリング Modelling of Damage Accumulation under Sintering of Particulate FGM A. Maximenko and O. Van Der BiestDepartement MTM, Katholieke Universiteit Leuven, W. De Croylaan 2, BE-3001 Heverlee, Belgium A. Maximenko and O. Van Der BiestDepartement MTM, Katholieke Universiteit Leuven, W. De Croylaan 2, BE-3001 Heverlee, Belgium  Formation of powder composites necessitates linking of components with different physical properties. Sintering is the most widespread method of imparting strength to powder body. Nevertheless, sintering of inhomogeneous media initiates the rise of internal stresses, that in some important cases provoke damage development. The model of damage formation is put forward and sintering of powder cladding is considered in the article. English