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National Institute for Materials Science

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[Functionally Graded Materials VIII (FGM2004) (pp.531-788)](https://mdr.nims.go.jp/datasets/efd2e617-87c8-4df7-8c26-4e77ad1ee11c)

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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 VIII (FGM 2004) Functionally Graded Materials VIII(FGM 2004) 28 2004-07-14 531-538 耐摩耗ソフト合金の自立型機能傾斜加工としてのトライボレイヤー形成 Tribolayer Formation as a Functionally Self-Grading Process in Soft Anti-Friction Alloys Rafael Schouwenaars, Victor H. Jacobo, Sara Cerrud and Armando Ortiz Rafael Schouwenaars, Victor H. Jacobo, Sara Cerrud and Armando Ortiz  Soft anti-friction alloys are metal-metal composites used in journal bearings as a functionally graded system. The physical processes occurring during severe wear of these products are analyzed and placed within the framework of theories on tribolayer formation. A simplified analysis of the thermodynamics of the phenomena permit analyzing the anti-friction properties of the alloys in terms of the activity coefficients of their constituents and indicates that during wear, a wear-resistant contact layer is formed which retards further damage. English Functionally Graded Materials VIII (FGM 2004) Functionally Graded Materials VIII(FGM 2004) 28 2004-07-14 539-544 プラズマ窒化FG-M(M=Ti, V,Al)合金の沈降 Precipitation in Plasma Nitrided Fe-M (M=Ti, V, Al) Alloys G.Miyamoto, Y.Tomio, T.Furuhara, T.Maki G.Miyamoto, Y.Tomio, T.Furuhara, T.Maki  Microstructures of the plasma nitrided ferritic Fe-M (M= 0.5, 0.7, 1.0mass%Ti, 1.0mass%V, 1.0mass%Al) binary alloys were studied mainly by TEM. Metastable clusters are uniformly formed in the Ti added alloys. Near the surface of the specimen, transition from the clusters to the equilibrium Bl-type TiN is observed. The microstructure formed in the 1%V alloy is similar to that of the Ti added alloy. In contrast, no cluster is formed in the 1%Al alloy and Bl-type AlN is observed to nucleate on dislocations. English Functionally Graded Materials VIII (FGM 2004) Functionally Graded Materials VIII(FGM 2004) 28 2004-07-14 545-550 スモールパンチクリープ試験法を用いた12Cr1MoVスチールのクリープ特性評価 Appraisement of Creep Properties of 12Cr1MoV Steel by Small Punch Creep Test Method Gang Chen, Peng-Cheng Zhai, Ai-Jun Shao Gang Chen, Peng-Cheng Zhai, Ai-Jun Shao  The numerical simulation for the Small Punch creep (SP-C) tests is conducted using a Finite Element method. The objective of the present study is to obtain the deformation states of the SP-C specimen and to estimate the feasibility of SP-C test method for high-temperature creep properties. The emphasis is put on the relationship between the equivalent creep strain is obtained by finite element method and the effects of the load, temperature and material properties on the relationship of central deflection and equivalent creep strain are discussed. From the numerical results, the relationship between the central deflection and the equivalent creep strain is approximately independent of load, temperature, and material properties. As a farther result, the high temperature creep properties of the 12CrlMoV steel are appraised by numerical simulation. The results are in good agreement with the results from the standard test method. The results indicate that the small punch test technique is an effective method for the evaluation of the high-temperature creep properties of materials. English Functionally Graded Materials VIII (FGM 2004) Functionally Graded Materials VIII(FGM 2004) 28 2004-07-14 551-554 MoSi2/SiC複合材の有効熱導電率 Effective Thermal Conductivity of MoSi2/SiC Composites G.Bai, W.Jiang, G.Wang, L.Chen, X.Shi G.Bai, W.Jiang, G.Wang, L.Chen, X.Shi  Thermal conductivity of as-prepared MoSi2/SiC composites has been determined by Laser Flash method. Interfacial thermal conductance for composites with 100nm SiC and with 0.5micrometer has been determined by using effective medium theory. The results of interfacial thermal conductance exhibit that both the inclusion size and the clustering of the inclusions play an important role in determining composite thermal conductivity. English Functionally Graded Materials VIII (FGM 2004) Functionally Graded Materials VIII(FGM 2004) 28 2004-07-14 555-560 超硬合金の硬度および降伏強度の相互関係 The Correlation between Hardness and Yield Strength of Hard Materials L.J.Vandeperre, W.J.Clegg L.J.Vandeperre, W.J.Clegg  The correlation between hardness, H, and yield strength, Y, for hard materials is re-examined using an analytical approach to provide a physical interpretation, which explains the trends observed. Existing analytical predictions using the analogy of the spherical cavity fail to reproduce experimental and finite element results because the accommodation of the intrusion of the indenter due to surface deformation is not taken into account, while experiments made here and elsewhere indicate that the latter can be substantial. A simple modification is proposed, which accounts for this, and allows for a reasonable prediction of the relation between hardness and yield strength for materials, which have a well determined yield point and do not strain harden. The treatment also allows explaining the effect of indenter geometry on measured hardness for such materials. English Functionally Graded Materials VIII (FGM 2004) Functionally Graded Materials VIII(FGM 2004) 28 2004-07-14 561-566 耐火性試験片の熱安定性挙動予測のための画像解析プログラムの利用 Using the Image Analysis Program for Prediction of Thermal Stability Behavior of Refractory Specimen T.Volkov-Husovic, R.Jancic, D.Mitrakovic T.Volkov-Husovic, R.Jancic, D.Mitrakovic  Most important properties which are usually measured for refractories are work temperature and thermal stability. Thermal stability of the alumina-based samples was measured using a standard laboratory procedure, the water quench test (JUS.B.D.8.319.). ImagePro Plus Program was used for image analysis of microphotographs of the samples before, during and after water quench test. Changes at the surface before, and after cycling were given. Mechanical characteristics were considered such as compressive strength, and dynamic modulus of elasticity. It was measured by resonance frequency measurements, as well as ultrasonic velocity. In this work the correlation between microstructure, ultrasonic velocity and strength on thermal stability of the sample were investigated. The obtained results were used for validation of the model to predict the thermal stability of the refractory of the refractory specimen. English Functionally Graded Materials VIII (FGM 2004) Functionally Graded Materials VIII(FGM 2004) 28 2004-07-14 567-572 ステンレス鋼／ジルコニア成形体の熱輸送特性：組成および温度 Thermal Transport Properties of Stainless Steel/Zirconia Compacts as a Function of Composition and Temperature Lars Halldahl, Mats Nygren Lars Halldahl, Mats Nygren  none English Functionally Graded Materials VIII (FGM 2004) Functionally Graded Materials VIII(FGM 2004) 28 2004-07-14 573-580 傾斜複合材の破壊・疲労亀裂伝播 Fracture and Fatigue Crack Propagation in Graded Composites Matthew Tilbrook, Lyndal Rutgers, Robert Moon, Mark Hoffman Matthew Tilbrook, Lyndal Rutgers, Robert Moon, Mark Hoffman  The propagation of cracks in graded materials under monotonic and cyclic loading was investigated via experiment and simulation. Graded alumina/epoxy composite specimens exhibiting a variation in composition from 5% to 65% epoxy, representing a twenty-fold variation in Young's modulus, across a region of width between 6 and 20 mm, were produced by a multistep infiltration technique. Crack initiation and propagation under monotonic and cyclic four-point bend loading was monitored and crack trajectories and growth rates were measured. Initial crack deflection was observed, in agreement with theoretical and computational predictions in the literature. Cracks exhibited further deviation as they traversed the graded region. Higher deflection angles were observed for specimens with steeper gradients, and for those with cracks initially located closer to the compliant side of the gradient.Homogeneous specimens in the composition range 5% to 55% epoxy were also produced to investigate the composition dependence of mechanical, fracture and fatigue properties for alumina-epoxy composites. Crack propagation resistance appeared to differ between monotonic and cyclic loading, though an increase with crack extension was observed in both cases. The significant variation in measured crack-propagation resistance, for cracks in graded specimens, was accordingly interpreted as a combination of crack extension effect and spatial variation of both intrinsic and extrinsic crack-growth resistance.A finite element model has been developed to simulate the propagation process, with particular attention paid to crack propagation and deflection criteria. Results from homogeneous specimens were utilized for estimating spatial property distribution and crack-extension effect in the graded specimens. Experimental results for crack path and crack-growth resistance profile show good agreement with modeling predictions. English Functionally Graded Materials VIII (FGM 2004) Functionally Graded Materials VIII(FGM 2004) 28 2004-07-14 581-586 セラミック積層の強度分布 Strength Distributions of Ceramic Laminates Javier Pascual, Francis Chalvet, Tanja Lube, Goffredo de Portu Javier Pascual, Francis Chalvet, Tanja Lube, Goffredo de Portu  In this work the strength of ceramic laminates is analyzed. Two different architectures with the same surface are studied. One of them, a Al2O3/Zr(3Y)O2 laminate, contains compressive residual stresses, the other one, a monolithic Al2O3 laminate, has no residual stresses. Residual stresses are estimated analytically on the basis of the materials properties and by an indentation technique. The influence of the residual stresses on the strength distribution is investigated. Strength distributions for laminates with compressive stresses at the surface follow a Weibull distribution only under certain conditions. English Functionally Graded Materials VIII (FGM 2004) Functionally Graded Materials VIII(FGM 2004) 28 2004-07-14 587-592 熱電気FGMのためのゼーベック走査型マイクロプローブ Seebeck Scanning Microprobe for Thermoelectric FGM D.Platzek, G.Karpinski, C.Drasar, E.Muller D.Platzek, G.Karpinski, C.Drasar, E.Muller  The FGM principle plays an important role in enhancing the efficiency of thermoelectric devices. While a thermoelectric generator (TEG) is typically operating in a large temperature difference, attractive conversion efficiency of a particular semiconductor is restricted to a small temperature range. Hence, when employing a semiconductor with its highest possible efficiency at the respective temperature in the internal temperature field along a stacked TEG, the overall conversion efficiency of the device may be considerably enhanced. Similarly, the FGM principle can be employed for linearization of thermal sensors. The output voltage (response) of the sensor is proportional to the Seebeck coefficient of the material the sensor is made of. Since the Seebeck coefficient is strongly temperature-dependent, the sensor response is not linear with temperature. However, combining in a stack two or more semiconductors which temperature dependence of the Seebeck coefficient are complementary to each other, results in a sensor with linear response (i.e. its output is proportional to the temperature difference, or heat flux, respectively.)Stacking of several materials to each other or grading a semiconducting sample requires a technique which can scan the Seebeck coefficient profiles S(x) along the stack. Accordingly a Seebeck micro-probe technique has been developed for scanning the surface of a sample monitoring S with a resolution of down to 10 micrometer within the temperature range from -15 deg.C to 60 deg.C. An additional option of such a device is the scanning of the electrical potential along the stuck under current flow. Thus, related experimental data on the local profiles of the electrical conductivity and Seebeck coefficient along the stack (or continuously graded FGM) will be available. The apparatus has been automated so that extended areas may be scanned providing two-dimensional images. Additionally, several samples can be scanned in one automatic run. English Functionally Graded Materials VIII (FGM 2004) Functionally Graded Materials VIII(FGM 2004) 28 2004-07-14 593-598 ナノTiO2粉末の調査：構造および粒子サイズ Investigation of Nano-Size TiO2 powders: Structure and Particle Size Aspects Hyung Mi Lim, Hyun-Bae Ji, Youn-Seoung Lee, Sun-Jae Kim, Hee-Soo Lee, Duk-Ho Cho Hyung Mi Lim, Hyun-Bae Ji, Youn-Seoung Lee, Sun-Jae Kim, Hee-Soo Lee, Duk-Ho Cho  Nano-size TiO2 powders were prepared by a homogeneous precipitation process at low temperature below 100 deg.C (HPPLT). The structure and particle sizes of these TiO2 powders were estimated by x-ray diffraction (XRD), Brunauer-Emmett-Teller (BET) and X-ray absorption spectroscopy (XAS) methods. The experimental results were found to have a very large specific surface; the results of XRD and BET method showed that particle size of HPPLTed TiO2 powders were ~10nm. The crystallinity of nano-sized HPPLTed TiO2 powders was also determined by XAS. English Functionally Graded Materials VIII (FGM 2004) Functionally Graded Materials VIII(FGM 2004) 28 2004-07-14 599-604 傾斜機能材料のクリープ特性 Creep Property of Functionally Graded Materials Peng-Cheng Zhai, Gang Chen and Qing-Jie Zhang Peng-Cheng Zhai, Gang Chen and Qing-Jie Zhang  The present paper investigates the creep phenomenon of the functionally graded materials under high temperature environment by the computational micromechanical method (CMM). Based on the real microstructure of the functionally graded interlayer with different component volume fractions, the emulation experiment is implemented for the creep test numerically and the creep parameters are obtained. A further series of simulation works are carried out to investigate the creep phenomenon of FGM interlayers in more detail. Numerical results show that the creep phenomenon is obvious not only for the metal-rich interlayers but also for the ceramic-rich interlayers. The creep property of ceramic/metal interlayer depends on the material's properties of the ceramic obviously. It is remarkable that the creep strain rate of the ceramic/metal interlayer is larger than the corresponding one of pure metal under the same load when the modulus of the ceramic component is lower than the one of the metal component. English Functionally Graded Materials VIII (FGM 2004) Functionally Graded Materials VIII(FGM 2004) 28 2004-07-14 605-608 TZ-3Y20A/Mo多層複合材の作製および機械的特性 Fabrication and Mechanical Properties of TZ-3Y20A/Mo Multilayer Composites Lianmeng Zhang, Lichun Yu, Daoren Gong, Qiang Shen Lianmeng Zhang, Lichun Yu, Daoren Gong, Qiang Shen  In the present work, TZ-3Y20A/Mo multilayer composites were prepared by sedimentation method. Appropriate settling parameters were chosen and green bodies of multilayer composites were obtained by settling TZ-3Y20A powder and Mo powder in turn according to the designed individual layer thickness. Then green laminates were hot pressed at 1773K for an hour under the pressure of 20MPa. Three-point Bending and Single Edge Notched Beam (SENB) tests were adopted to evaluate the flexure strength and fracture toughness of the samples. The results showed that, compared to TZ-3Y20A ceramics, the fracture toughness and the work of fracture increased due to the layered structure. The microstructure and crack deflection of the fracture surface of the laminated composites was also observed by optical microscopy. English Functionally Graded Materials VIII (FGM 2004) Functionally Graded Materials VIII(FGM 2004) 28 2004-07-14 609-614 遠心法で作製されたAl-Al3ZrおよびAl-Al3TiFGMsの粒子分布および配向性 Particle Distribution and Orientation in Al-Al3Zr and Al-Al3Ti FGMs Produced by the Centrifugal Method P.D.Sequeira, Yoshimi Watanabe, L.A.Rocha P.D.Sequeira, Yoshimi Watanabe, L.A.Rocha  Al-Al3Zr and Al-Al3Ti functionally graded materials (FGMs) were produced by a centrifugal method from Al-5wt%Zr and Al-5wt%Ti alloys, respectively. Applied centrifugal forces were 30, 60 and 120G (unites of gravity). Microstructural characterization was performed to evaluate the intermetallic particles' distribution and orientation. Knoop hardness tests were carried out, with the indenter's long diameter normal to the centrifugal force direction. Both the Al3Zr and the Al3Ti intermetallic particles are platelet in morphology. These platelets tend to be oriented normal to the centrifugal force direction. Higher applied centrifugal force increases both the intermetallic platelet volume fraction as well as their orientation in the outer regions of the fabricated FGM rings. Also higher orientation and volume fraction distribution are observed in the Al-Al3Ti FGMs. Knoop hardness measurements in general follow the same trend as the intermetallic particle volume fraction for each sample. English Functionally Graded Materials VIII (FGM 2004) Functionally Graded Materials VIII(FGM 2004) 28 2004-07-14 615-620 マイクロ傾斜粒子構造構成を持つ複合材料の規則性 Regularities of Composite Materials with Micrograded Grain Structure Formation V.V.Kurbatkina, E.A.Levashov V.V.Kurbatkina, E.A.Levashov  Composite carbide materials in Ti-C, Ti-Nb-C, Ti-Zr-C systems were produced by combustion synthesis using the force SHS-pressing technology and investigated. Composition and structure of the synthesis products before and after annealing at 850 deg.C, 1 hour were studied using optical and SEM, X-ray diffraction and Auger Electron Spectroscopy. It was established that SHS-products consist of two main phases: TiC0.6 + beta-Ti, (Ti, Nb)C1-x + beta-(Ti, Nb), (Ti, Zr)C1-x + beta-(Ti, Zr). Structure of these composite materials presented by carbide phase with a grain size varying 4-8 micrometer, and surrounded intergranular thin layer of beta-Ti solid solution with width less than 1.5 micrometer. Composition and structure of carbide grains and intergranular phase just after combustion process is not equilibrium: supersaturated solid solutions are formed because of high temperature gradient and combustion velocity. Annealing results in an equalization of the solid solution composition. Carbide grains content precipitations sized 20-200 nm based on solid solution (Me-Ti). Two possible schemes of concentration separation of supersaturated solid solution were discussed:(Ti, Nb)x+yC = (Ti, Nb)xC1-x+y(Nb-Ti) and (Ti,Zr)x+yC = (Ti, Zr)xC1-x+y(Ti-Zr).Lattice parameter of the intraganular phase differs from the matrix ones. Graded distribution of Nb and Zr alloying elements inside the carbide grains was observed. The developed composite materials strengthened by nano- or microsized particles are attractive for high-temperature applications. English Functionally Graded Materials VIII (FGM 2004) Functionally Graded Materials VIII(FGM 2004) 28 2004-07-14 621-626 シンクロトロン放射ホログラフィックマイクロトモグラフィーによる傾斜機能Al/SiCp複合材のSiC粒子の結合性評価 Evaluation of SiC-particle Connectivity in Functionally Graded Al/SiCp Composites by Synchrotron Radiation Holographic Microtomography A.Velhinho, G.L.Vignoles, P.Cloetens, X.Thibault, E.Boller, F.Braz Fernandes, L.A.Rocha, J.D.Botas A.Velhinho, G.L.Vignoles, P.Cloetens, X.Thibault, E.Boller, F.Braz Fernandes, L.A.Rocha, J.D.Botas  Reliability of functionally graded metal matrix composites (FGMMCs) for automotive components is still dependent on the detailed knowledge of the mechanisms of the microstructural build-up, for instance on the mechanisms leading to the distribution and relative positions of the reinforcing particles. In order to assess the influence of the SiC particle size on the 3-D inter-particle connectivity in functionally graded Al/SiCp composites produced by centrifugal casting, X-ray microtomography experiments were performed at the ID19 beamline in ESRF (European Synchrotron Radiation Facility). The FGMMCs consisted of an Al-10Si-2Mg alloy matrix, reinforced by an average SiC particle volume fraction of 0.10; two different average sizes were used: 37 micrometer and 12 micrometer. The holographic modification of the X-ray CMT (Computer Micro-Tomography) method allowed obtaining neatly contrasted images, as opposed to classical CMT. Good agreement was found between the particle size evaluated by CMT and by laser interferometry. Particle clustering has been evaluated in number and volume, showing that a lower mean particle size is related to more clustering. Such an adverse effect relies on the importance of particle/liquid alloy surface tension. Also, the mean particle size has been evaluated as a function of particle number within a cluster: as expected, the larger a cluster, the larger the particles inside it. English Functionally Graded Materials VIII (FGM 2004) Functionally Graded Materials VIII(FGM 2004) 28 2004-07-14 627-634 電子プローブマイクロ解析：スチール製品の欠陥調査における新たな発見 Electron-Probe Microanalysis: Some Revelations in the Investigation of Defects in Steel Products Amitava Ray Amitava Ray  The unique imaging and microanalytical capability of the electron-probe microanalyser (EPMA) has been exploited in conjunction with light microscopy for exploring the genesis of some defects, which are detrimental to steel product quality. Investigations of surface and internal defects have revealed that defects in the finished steel product are often inherited at upstream stages and accentuated in the later stages of steel processing.While the occurrence of surface defects such as "slivers" in hot-rolled sheets and "linear cracks" in hot rolled rounds has been largely attributed to subsurface non-metallic inclusions and slag/casting powder entrapment, microprobe analysis of internal defects such as "centre-line cracking" of thick plates have revealed the deleterious role of C and Mn macrosegration inherited during the continuous casting of steel slabs. The paper elucidates some of these findings, as unraveled by both qualitative and quantitative microprobe analysis. English Functionally Graded Materials VIII (FGM 2004) Functionally Graded Materials VIII(FGM 2004) 28 2004-07-14 635-640 多機能材料の特性評価による基準材料の保証 Certified Reference Materials for the Characterization of Multifunctional Materials Gert Roebben, Uwe Watjen, Andree Lamberty Gert Roebben, Uwe Watjen, Andree Lamberty  Multifunctional materials are created by intimately integrating different materials. The assessment of the local properties and composition of the different components of such a multifunctional material necessarily relies on techniques with sufficient spatial resolution. The increased use of these microanalysis or microprobe techniques has created a demand for appropriate quality assurance tools, such as reference materials. In this paper a number of issues related to the certification of reference materials for multifunctional materials are discussed. Examples of reference materials are shown to illustrate the particular challenges the reference material producer is faced with such as micro-homogeneity minimum sample intake and stability. English Functionally Graded Materials VIII (FGM 2004) Functionally Graded Materials VIII(FGM 2004) 28 2004-07-14 641-646 Al2O3/ZrO2 FGMディスクの研磨断面の応力緩和のラマン分光法による測定 Stress Relaxation on Polished Cross-Sections of Al2O3/ZrO2 FGM Discs Measured by Raman Spectroscopy Guy Anne, Kim Vanmeensel, Jef Vleugels, Omer Van der Biest Guy Anne, Kim Vanmeensel, Jef Vleugels, Omer Van der Biest  The residual stresses were measured on polished cross-sectioned Al2O3/ZrO2 FGM discs by means of Raman spectroscopy. The experiments revealed that it is possible to measure the residual stresses caused by the thermal expansion mismatch between the alumina and zirconia phase as a function of the position in the FGM. These experimental data are in excellent agreement with the thermal stresses calculated from the local composition using the model of Taya. However, the stresses due to the generated FGM profile could not be measured by means of Raman spectroscopy, due to stress relaxation upon cross sectioning of the FGM disc. English Functionally Graded Materials VIII (FGM 2004) Functionally Graded Materials VIII(FGM 2004) 28 2004-07-14 647-652 ガラスーアルミナ傾斜機能面の実験的特性評価および計算シミュレーション Experimental Characterization and Computational Simulation of Glass-Alumina Functionally Graded Surfaces V.Cannillo, T.Manfredini, M.Montorsi, C.Siligardi, A.Sola V.Cannillo, T.Manfredini, M.Montorsi, C.Siligardi, A.Sola  Functionally graded materials are a new and attractive class of materials incorporating an engineered spatial variation in composition and/or microstructure: this idea has immediately revealed successful since it allows reaching peculiar mechanical properties such as resistance to wear and contact damage. As a matter of fact, the final behavior of a Functionally Graded Material is mainly influenced by its graded composition and/or microstructure. Therefore, a good fabrication technique should provide a high control and reproducibility of the spatial variation in composition and/or microstructure; on the other hand, a reliable model should take into account the gradient in order to accurately predict the final behavior of a Functionally Graded Material. The present study is focused on glass-alumina FGMs: the compositional variation, which occurs along only one direction, has been realized through percolation of a molten glass into a bulk polycrystalline alumina. The resulting Functionally Graded Coatings have been carefully characterized through Scanning Electron Microscopy, X-ray diffraction, classical mechanical tests and analysis. Moreover, their behavior has been modeled by means of a microstructure-based FEM method. A great attention has been paid to the validation of the computational model based on the experimental data. Furthermore, the experimental and the computational approaches have been combined in order to define the correlation between fabrication parameters, such as time and temperature, and resulting gradients in composition and microstructure as well as related performances. Since changes in material response to a given thermo-mechanical loading and to tailor the gradient as a function of the specific application. English Functionally Graded Materials VIII (FGM 2004) Functionally Graded Materials VIII(FGM 2004) 28 2004-07-14 653-658 数値ー実験混合法による円筒型熱遮蔽コーティングの各構成層の弾性率の決定 Determining the Elastic Module of the Individual Component Layers of Cylindrical Thermal Barrier Coatings by means of a Mixed Numerical-Experimental Technique T.Lauwagie, K.Lambrinou, I.Mircea, M.Bartsch, W.Heylen, O.Van der Biest T.Lauwagie, K.Lambrinou, I.Mircea, M.Bartsch, W.Heylen, O.Van der Biest  Cylindrical specimens made of the Ni-based super-alloy Inconel 625 (IN 625) were coated with (a) NiCoCrAlY, or (b)NiCoCrAlY and yttria-stabilized zirconia (YSZ: in this case, zirconia with 7-8 wt% yttria), using the electron beam-physical vapor deposition (EB-PVD) technique. In the bi layer coatings, the YSZ layer is the thermal barrier coating (TBC) and the NiCoCrAlY layer is the metallic bond coat (BC). The BC improves the bonding between the substrate and the ceramic TBC, while the low thermal conductivity of the TBC offers high-temperature protection to the substrate. This paper focuses on the determination of the elastic module of the substrate and the coating layer of the test samples. The elastic modules of the three different materials (IN625, NiCoCrAlY and YSZ) were determined by means of a mixed numerical-experimental technique (MNET). The employed MNET was based on the comparison of the experimental technique (MNET). The employed MNET was based on the comparison of the experimentally measured ones. The unknown elastic properties were determined by fine-tuning the elastic material parameters of the numerical models so as to enable the reproduction of the experimentally measured resonant frequencies. English Functionally Graded Materials VIII (FGM 2004) Functionally Graded Materials VIII(FGM 2004) 28 2004-07-14 659-664 低エネルギーイオンビーム放射によるポリイミド表面改良 Polyimide Surface Modification by Low Energy Ion Beam Irradiation W.J.Lee, Y.S.Lee, S.K.Rha, K.Y.Lim, H.S.Lee, C.N.Whang W.J.Lee, Y.S.Lee, S.K.Rha, K.Y.Lim, H.S.Lee, C.N.Whang  The surface modification of polyimide(PI) by the irradiation of 3 keV He+, Ne+ and Ar+ ions was studied using XPS and AFM at various ion dose ranging from 1*10**14 to 1*10**17 ions/cm**2. The change of surface roughness of PI by 3keV inert ions was closely connected to the change of surface composition. At low doses below 5*10*15 ions/cm**2, the surface of polyimide was carbonized by ion irradiations, showing rough surface. At higher ion doses, the surface composition was saturated due to the accumulation of damages, and the surface morphology became smoother as compared with the low dose case. English Functionally Graded Materials VIII (FGM 2004) Functionally Graded Materials VIII(FGM 2004) 28 2004-07-14 665-670 修正スリップキャスティング作製によるAl2O3-Fe FGMの微細構造 Microstructure of Al2O3-Fe FGM Obtained by Modified Slip-Casting Method A.Ozieblo, T.Wejrzanowski, K.Konopka, M.Szafran, K.J.Kurzydlowski A.Ozieblo, T.Wejrzanowski, K.Konopka, M.Szafran, K.J.Kurzydlowski  This paper describes the technology and microstructure of Al2O3-Fe functionally graded composites, FGM, obtained by slip casting under magnetic field. Alumina alpha-Al2O3, provided by Alcoa (symbol A16SG), with average grain size of 0.5 micro meter, and iron powder, (symbol Distaloy AB) from Hoganas, with average grain size of 35 micro meter, were used to product a series of specimens which differed in contents of Fe particles in Al2O3. As a sauce of magnetic force, a permanent magnet was used. Preforms were sintered in a vacuum at temp.1470 deg.C.The microstructures of the specimens were quantitatively described via stereological methods. Sections, parallel to the magnetic field lines were analyzed using special image analysis software. Stereological methods presented in this work have been to determine gradient in the volume fraction of the Fe particles and variation in their size and dispersion. These parameters are essential for controlling the technological process of interest and to design microstructure for needed properties (fracture toughness). English Functionally Graded Materials VIII (FGM 2004) Functionally Graded Materials VIII(FGM 2004) 28 2004-07-14 673-678 微細構造が大きく変化した積層ボロンカーバイドーアルミニウム複合材 Layerd Boron Carbide-Aluminum Composites with Large Changes in Microstructure Hyun Jun Kim, Kevin P.Trumble, Keith J.Bowman Hyun Jun Kim, Kevin P.Trumble, Keith J.Bowman  Melt infiltration of preforms prepared by sequential centrifugal casting and by tape casting and lamination has been accomplished using a short-time infiltration process that significantly suppresses reaction product formation. For layered materials produced via infiltration of laminated ceramic tapes, of particular interest is the effect that a large change in microstructure has on infiltration, phase formation and mechanical properties. English Functionally Graded Materials VIII (FGM 2004) Functionally Graded Materials VIII(FGM 2004) 28 2004-07-14 679-684 ナノ粒子インク使用の３D印刷で作製された材料傾斜を持つ鉄鋼部品 Steel Parts with Tailored Material Gradients by 3D-Printing using Nano-Particle ink Dirk Godlinski, Stephane Morvan Dirk Godlinski, Stephane Morvan  It is difficult to generate any user-defined three-dimensional gradient to tailor the functional properties of a component. Problems are not only the lack of local material design tools, but also a suitable manufacturing process. The implementation of the concept of local composition control into the Solid Freeform Fabrication (SFF) process 3D-Printing is described, which leads to geometrical complex parts out of tailored materials. Suspensions of different functional inks containing a binder and carbon black nano-particles are dispensed into droplets through multiple jets-like inkjet printing a halftone image on a paper-but into a metal powder bed to generate layer by layer graded green parts. In this case the tailored performs are then sintered, while the nano-particle additions from the functional ink act locally as alloying elements in the steel matrix to combine e.g. both, toughness and hardness in the part. This work concentrates on the realization of the new process and shows first results taking the generation of carbon-graded steel parts as an example. English Functionally Graded Materials VIII (FGM 2004) Functionally Graded Materials VIII(FGM 2004) 28 2004-07-14 685-692 高密度傾斜機能B４C強化複合材料の燃焼合成 Combustion Synthesis of Dense Functionally Graded B4C Reinforced Composites I.Zlotnikov, I.Gotman, L.Klinger and E.Y.Gutmanas I.Zlotnikov, I.Gotman, L.Klinger and E.Y.Gutmanas  Dense FGMs with gradually changing fraction of very hard and lightweight B4C particles were fabricated employing an original Reactive Forging (RF) combustion synthesis method. In RF, a self-sustained reaction (thermal explosion, TE) is ignited by placing a powder blend between preheated press rams and the high temperature achieved is utilized for consolidation of the combustion product. The reported FGMs were prepared by stacking layers of highly exothermic Ti-C-Ni powder blend diluted with varying fractions of non-reacting B4C particles. Only a limited amount of B4C could be added as its diluting action reduces the overall exothermic of the blend. In some cases, B4C particles were precoated in order to prevent their interaction with Ti during combustion.Temperature evolution in (Ti-Ni-C)-B4C powder compacts corresponding to different FGM layers was measured separately and in the stacked form. The better understanding of combustion process in B4C-diluted blends coupled with well-devised geometrical design allowed us to fabricated FGMs with high volume fractions of B4C in the surface layer. English Functionally Graded Materials VIII (FGM 2004) Functionally Graded Materials VIII(FGM 2004) 28 2004-07-14 693-698 in-situ遠心法によるFGM作製中の組成傾斜形成 Formation of Compositional Gradient during Fabrication of FGMs by a Centrifugal in-situ Method Yoshimi Watanabe, Shin Oike, Ick-Soo Kim Yoshimi Watanabe, Shin Oike, Ick-Soo Kim  The purpose of the present work is to study the formation of the compositional gradient during the fabrication of FGMs by a centrifugal in-situ method. Al-Al2Cu FGMs were fabricated by the centrifugal in-situ method using eutectic Al-33mass%Cu alloy, and the microstructures of fabricated FGMs were studied. It was found that the Al-Al2Cu FGMs could be fabricated by the centrifugal in-situ method from eutectic alloy. Based on the experimental results, the formation mechanism of the compositional gradient during the fabrication of FGM by the centrifugal in-situ method in the A-B alloy could be summarized as follows; 1) Partial separation of A and B elements in the liquid state occurs due to the density difference. 2) A compositional gradient is formed before the crystallization of the primary crystal. 3) The primary crystals in the matrix appear to depend on local chemical composition. 4) The primary crystals migrate according to density difference, and a further compositional gradient is formed. English Functionally Graded Materials VIII (FGM 2004) Functionally Graded Materials VIII(FGM 2004) 28 2004-07-14 699-704 不活性雰囲気中での焼鈍しによるAl2O3/Ce-TZP傾斜機能材料の靭性強化 Toughness Enhancement of Al2O3/Ce-TZP Functionally Graded Materials by Annealing in Inert Atmosphere Jef Vleugels, Chao Zhao and Omer Van Der Biest Jef Vleugels, Chao Zhao and Omer Van Der Biest  CeO2-stabilised ZrO2-based functionally graded materials (FGMs) can be successfully produced using electrophoretic deposition and pressureless sintering in air. A cylindrical Al2O3/ZrO2 FGM, for instance, shows an ideal structure for applications such as drill blanks. It has a central hole with a diameter less than 0.5mm, a tough Ce-ZrO2 core with a diameter of about 3mm, a gradient layer, of about 1mm, and a hard Al2O3-rich surface layer. The Ce-ZrO2 core shows Vickers hardness between 10 and 11 GPa and an excellent toughness (>10MPa m**1/2). In the gradient layer, hardness and toughness vary continuously along the radius. The Al2O3-rich surface layer has a hardness of 15.2 GPa but a modest toughness of 2MPa m**1/2. Annealing experiments of the air-sintered FGM in inert atmosphere (Ar + 5vol%N2) allows a significant toughness enhancement, especially in the surface layer (up to 8 MPa m**1/2). The experimental results indicate that a proper controlled reduction of the Ce-TZP phase allows a modification of the toughness of the Ce-TZP phase. The influence of the annealing cycle on the properties of the FGM are reported and elucidated. English Functionally Graded Materials VIII (FGM 2004) Functionally Graded Materials VIII(FGM 2004) 28 2004-07-14 705-710 電気泳動法によるAl2O3-ZrO2-Ti(C,N)系傾斜セラミック切削ツールの加工 Processing of a Graded Ceramic Cutting Tool in the Al2O3-ZrO2-Ti(C, N) system by Electrophoretic Deposition K.Vanmeensel, G.Anne, D.Jiang, J.Vleugels, O.Vam der Biest K.Vanmeensel, G.Anne, D.Jiang, J.Vleugels, O.Vam der Biest  In this study, the development of a functionally graded material (FGM) with hard outer surfaces and a tougher inner core was envisaged. The applicability of electrophoretic deposition (EPD) for the processing of FGM materials by continuously changing the suspension composition is shown. Optimization of the colloidal processing technique was combined with hot pressing experiments on homogeneous composites in the Al2O3-ZrO2-Ti(C,N) system in order to create a very hard functionally graded material with beneficial residual stresses. Finally, the residual stress distribution was briefly discussed using an existing analytical model. English Functionally Graded Materials VIII (FGM 2004) Functionally Graded Materials VIII(FGM 2004) 28 2004-07-14 711-718 放電プラズマ焼結(SPS)作製による正方形の大型WC/Co/Ni系FGMの開発および実用化 Development of Square-shaped Large-size WC/Co/Ni system FGM Fabricated by Spark Plasma Sintering (SPS) Method and Its Industrial Applications Masao Tokita Masao Tokita  As a typical high wear-resistant hard material, WC/Co system cemented carbides are now widely used in various press-stamping dies and cutting tools for industrial applications. In recent years in Japan, a rapid sintering method called Spark Plasma Sintering (SPS) method or Pressure assisted Pulsed Electric Current Sintering (PECS) method has attracted attention to fabrication of dense bulk Functionally Graded Materials (FGMs) and Nano-phase materials. In order to improve the mechanical properties of monolithic hard materials into the surface with high wear-resistance and the inside with high toughness with more functionality, a compositionally graded WC/Co/Ni system FGM was studied. Using an Automatic FGM Manufacturing SPS machine, Square-shaped Large-size WC/Co/Ni system FGMs of 70mm (width) * 100mm (length) * 8-60mm (thickness) with 3-layers graded composition of WC0.5 micrometer/ Co6 wt%, WC3.5 micrometer / Co15wt% and WC5micrometer / Ni20wt% were homogeneously fabricated in a cycle time of one per less than one hour. The hardness of the top and bottom layers containing 6wt%Co, 20wt%Ni were 20GPa and 8GPa respectively. The grain growth of the 0.5, 3.5 and 5 micrometer WC starting powder particles were minimized and well controlled. WC/Co and WC/Ni FGM systems were also studied. The developed WC/Co/Ni FGM showed a new weldable function to normal steel materials without any cracks and delaminations. The FGMs were practically applied to a screw component of extruding machine as the practical industrial use. It was successfully achieved more than 3 times longer tool lifetime at economical running cost. The gradient functions in both of weldability and machinability contribute to the application field in Tool & Die industry. English Functionally Graded Materials VIII (FGM 2004) Functionally Graded Materials VIII(FGM 2004) 28 2004-07-14 719-724 ステレオリソグラフィー作製によるメンジャースポンジ構造エポキシ／セラミックフォトニックフラクタルにおける電磁波の強力な局在化 Strong Localization of Electromagnetic Wave in Epoxy/Ceramic Photonic Fractals with Mengersponge Structure Fabricated by stereolithography Soshu Kirihara, Mitsuo Wada Takeda, Kazuyuki Sakoda, Katsuya Honda, Yoshinari Miyamoto Soshu Kirihara, Mitsuo Wada Takeda, Kazuyuki Sakoda, Katsuya Honda, Yoshinari Miyamoto  Menger-sponge is a three-dimensional fractal structure with self-similar patterns. We fabricated the Menger-sponge structure composed of epoxy with titania-based ceramic particles dispersion by using a stereo lithography CAD/CAM system. It has a cubic body of 27mm in edge size with square through holes of 1, 3, and 9mm. The structure is characterized with a fractal dimension D=2.73 and a fractal stage 3. The electromagnetic wave response of the Menger-sponge was measured by using a network analyzer. Both reflection and transmission amplitudes of incident waves showed remarkable attenuations to -50 dB at 8 GHz simultaneously. The electric field intensity in the center holes in the Menger-sponge was measured by using a mono-pole antenna. The electromagnetic energy was confined in the central air cavity by forming the strong localization mode. The localized mode frequency can be controlled by changing the structure size, number of stage, and the effective dielectric constant. We call such fractal structures as the photonic fractal referring to the photonic crystal. This new type structure of dielectric material is expected to provide various functions such as perfect absorption, localization, resonation, amplification, accumulation, and filtration of electromagnetic waves in wide range from microwave to light. English Functionally Graded Materials VIII (FGM 2004) Functionally Graded Materials VIII(FGM 2004) 28 2004-07-14 725-730 燃料電池応用におけるマルチモーダルなセリア粉末混合物の焼結挙動 Sintering Behavior of Multimodal Ceria Powder Mixtures for Fuel Cell Applications G.Falk, N.Bohm, M.Wolff, R.Clasen G.Falk, N.Bohm, M.Wolff, R.Clasen  Sub-micro scaled CGO(Ce0.9Gd0.1O1.95) powder is used in order to manufacture Ni/CGO functionally graded green bodies with high green densities. Thereby the near-shape manufacturing of Ni/CGO cermets by gel casting of CGO and Ni powder mixtures and electrphoretic impregnation of sub-micro scaled ceria doped particles into a Ni/CGO mesoporous matrix is described. Solids content of dispersed suspension is varied as well as the mixing ratio of sub-micro sized and micro sized particles. The influence on green density and sintering behavior is investigated in order to achieve maximum CGO densities in combination with maximum ionic conductivity for potential use in SOFC.Shrinkage rates from sintering experiments with constant rates of heating (CRH) are analyzed to determine most suitable co-sintering conditions of Ni-Ni/CGO composite anode materials. English Functionally Graded Materials VIII (FGM 2004) Functionally Graded Materials VIII(FGM 2004) 28 2004-07-14 731-736 連続結晶化による大型NaXゼオライト結晶の合成および特性評価 Synthesis and Characterization of Large NaX Zeolite Crystals by Continuous Crystallization  Hae Jin Lee, Hyung Mi Lim, Ik Jin Kim Hae Jin Lee, Hyung Mi Lim, Ik Jin Kim  NaX zeolite crystals of 50micrometer were grown by a continuous crystallization with seed crystal (10micrometer) in a mother solution having a 3.5Na2O:Al2O3:2.1SiO2:1000H2O composition. The seed crystal morphology of NaX zeolite shows that an octahedron is formed composed of 8 equilateral triangles which have an average lattice constant of a=24.9911 angstrom with a SiO2/Al2O3 molar ratio of 2.1-2.4. In order to grow crystals of zeolite X to an appropriate size by the continuous method, the mother  solution was supplied with various seed contents (3-20 wt%) in an autoclave at 90deg.C after 7, 12, 16, 19 and 24 days. English Functionally Graded Materials VIII (FGM 2004) Functionally Graded Materials VIII(FGM 2004) 28 2004-07-14 737-742 ナローホール(narrow holes)法における反応により作製された繊維強化金属の繊維／銅マトリックス界面の傾斜微細構造 Graded Microstructure at Fiber/Copper Matrix Interface in FRM Fabricated by the Reaction at Narrow Holes Method Yasuhiko Tanaka, Takeshi Goto, Yoshimi Watanabe Yasuhiko Tanaka, Takeshi Goto, Yoshimi Watanabe  The reaction at narrow holes method (RANH method) has been proposed for fabricating fiber reinforced metal (FRM), such as an intermetallic compound fiber/metal matrix composite. This study clarifies a microstructure at a fiber/metal matrix interface of FRM fabricated by using a combination of pure-copper and pure-aluminum in the RANH method. Pure-aluminum fiber was inserted into a narrow hole drilled in the copper matrix. The assembly comprising the pure-aluminum fiber and the pure-copper matrix was heated to a temperature greater than eutectic temperature of the copper-aluminum binary alloy. A molten aluminum reacted with copper to form an annular reacted region consisting of gamma1 intermetallic compound in a single phase near the edge of the narrow hole. The gamma1 intermetallic compound has very high hardness on the order of 800-900 HV. The annular reacted region may have a high tensile strength and may work as a reinforcing metal fiber in FRM. English Functionally Graded Materials VIII (FGM 2004) Functionally Graded Materials VIII(FGM 2004) 28 2004-07-14 743-748 層状複水酸化物の合成へのマイクロ波加熱の影響 Effect of Microwave Heating  on the synthesis of Layered Double Hydroxide  Hyung Mi Lim, Mi Ra Kang, Sang Chun Lee, Seung-Ho Lee, Kwang Jin Kim Hyung Mi Lim, Mi Ra Kang, Sang Chun Lee, Seung-Ho Lee, Kwang Jin Kim  Layered double hydroxide (LDH) was synthesized from the mixture of magnesium hydroxide and aluminum hydroxide with microwave irradiation. It has been compared with that of conventional heating method in the respect of crystallization time, structure, morphology, particle size, and its anion exchange capacity. The microwave speeded up the crystallization rate of Mg-Al-LDH so that the XRD patterns of LDH was observed from the sample after microwave hydrothermal treatment, while the crystal phase was hardly observed from that prepared by conventional hydrothermal method before drying process. Mg-Al-LDH prepared with microwave irradiation seemed to have slightly higher Mg/Al molar ratio even with the same compositions of starting materials and the lower anion exchange capacity after 1 day exposure in 0.1N NaCl solution compared to the conventionally prepared one. English Functionally Graded Materials VIII (FGM 2004) Functionally Graded Materials VIII(FGM 2004) 28 2004-07-14 749-754 選択層焼結法（SLS）のための３D機能傾斜の作製 Preparing 3D Functional Gradients for SLS Shoufeng Yang, Julian R.G.Evans Shoufeng Yang, Julian R.G.Evans  The creation of three dimensional functional graded material by powder processing methods requires the capability to arrange a sequence of two dimensional images that can be presented to a solid free forming device. Planar stacking methods can only achieve a one-dimensional gradient. We describe the acoustic control of powder metering and dispensing valves in which the flow rate and switching of powders from a capillary can be controlled using the frequency and amplitude of acoustic vibration from a computer sound card. An orchestra of such valves can be used to pattern layers of powder on the building platform which forms part of a 3-axis table in the Selective Laser Sintering (SLS) process. Patterns and gradients were prepared using copper and steel powders. English Functionally Graded Materials VIII (FGM 2004) Functionally Graded Materials VIII(FGM 2004) 28 2004-07-14 755-760 気孔傾斜多孔質アルミナチューブの作製および特性評価 Fabrication and Characterization of Porous Alumina Tube with Pore Gradient C.H.Chen, K.Takita, S.Ishigro, S.Honda, H.Awaji C.H.Chen, K.Takita, S.Ishigro, S.Honda, H.Awaji  The porous alumina tube with pore gradient along the radial direction was successfully fabricated, where PMMA particles were used as pore former agent. The specimen was expected as a filter subjected to high temperatures. Alumina and PMMA particle were mixed with water to form aqueous slurry, compacted using centrifugal molding technique. The green body was dried in partial vacuum atmosphere, calcinated at 273K to remove the organic component, sintered at 1623K to obtain sintered porous alpha-alumina tubes. The control on the pore gradient of porous tubes was attempted by two ways; lamination and continuous methods. The microstructure observation showed that the inner part of the tubes had higher porosity than the outer part irrespective of the method used. Porous alumina tubes were characterized by microstructure observation, porosity and air permeability. The binary pores of 10micrometer and submicron in diameter were visible, which were formed by the burning-out PMMA particles and lower sintering temperature, respectively. The influence of PMMA amount on the pore morphology of the tubes was investigated. Fracture strength was carried out by the O-ring diametral compression testing. An analytical formula subject to the diametral testing was introduced with considering the porosity gradient. The correlations between the fracture strength and pore gradient were investigated, where a reduction in fracture strength was observed with the increase in laminated layers, and minimum strength was found in continuous porous tubes. English Functionally Graded Materials VIII (FGM 2004) Functionally Graded Materials VIII(FGM 2004) 28 2004-07-14 761-764 FGMの低コスト製造技術 Technology of Low Cost Production of FGMs Katsuto Kisara, Masayuki Niino, Hironori Noguchi Katsuto Kisara, Masayuki Niino, Hironori Noguchi  In this paper, we introduced research and development of technology of low cost production of FGMs. This research is designated for development of mass production technology for production of ceramic wares with induction heating (IH) function. Slurry lamination method has advantage in forming graded layers due to its simplicity and easiness. However, this method has a disadvantage to generate cracks during drying process. Therefore, freeze-dry in vacuum was introduced in drying process of slurry lamination. By doing so, mass production could be achieved. In this trial production, we adopted SPS sintering method to production technique. In the future, we will further develop other applications of FGMs into industrial products. English Functionally Graded Materials VIII (FGM 2004) Functionally Graded Materials VIII(FGM 2004) 28 2004-07-14 765-770 積層金属粉体ホットプレス鋳造による多孔質傾斜材料 Porous Graded Materials by Stacked Metal Powder Hot-Press Molding Kazuyuki Nishiyabu, Satoru Matsuzaki, Kenji Okubo, Masashi Ishida, Shigeo Tanaka Kazuyuki Nishiyabu, Satoru Matsuzaki, Kenji Okubo, Masashi Ishida, Shigeo Tanaka  The production method for metal components with micro sized porous structure has been developed by applying "powder space holder method" to metal powder injection molding process. In this study, a co-sintering process was utilized to make a plate of sintered metal with micro porous graded structure. The green compact sheets with various contents of space hold particles were prepared by hot press molding for simplification. The five layers of metal with symmetric structure, which the skin layer was formed with high density metal and the core was formed with open or closed porous structure, or with inverse symmetry, was obtained by changing stacking sequence in co-sintering process. Mechanical properties of the materials with plain homogeneous porous structure and porous graded structure were compared. The usefulness of proposed method for producing the metal components with micro porous graded structure and the effective of graded structure to compensate the deficiencies on the mechanical property of porous metals was shown. English Functionally Graded Materials VIII (FGM 2004) Functionally Graded Materials VIII(FGM 2004) 28 2004-07-14 771-776 OFC-TC4の接合および接合界面の構造制御 Joining of OFC to TC4 and Structural Control of Joint Interface Chuanbin Wang, Lianmeng Zhang, Qiang Shen Chuanbin Wang, Lianmeng Zhang, Qiang Shen  In the present work, oxygen-free-copper (OFC) and Ti-6Al-4V (TC4) were joined by diffusion welding at first and then the structural control of the joint interface was mainly analyzed. It was found that firmly welded OFC/TC4 joint was obtained over a temperature range of 1023K-1103K, and the temperature played the key role which mainly affected the thickness of the joint interface. The results also showed that the joining of OFC to TC4 was attributed to the mutual diffusion effect of elements Cu and Ti. The structure of the joint interface was further controlled by exerting restrictive pressure (10MPa), controlling heating and cooling rates, lower welding temperature and reducing welding time etc. Finally, under certain welding parameters and by employing rational structural control techniques, well welded OFC/TC4 joint without large distortion or damage was obtained. English Functionally Graded Materials VIII (FGM 2004) Functionally Graded Materials VIII(FGM 2004) 28 2004-07-14 777-782 Al2O3-ZrO2FGMのコロイド成形のための懸濁液開発 Suspension Development for Colloidal Shaping of Al2O3-ZrO2 FGMs A.M.Popa, G.Anne, J.Vleugels, A.Foissy, O.Van der Biest A.M.Popa, G.Anne, J.Vleugels, A.Foissy, O.Van der Biest  This paper reports on the development of suitable ethanol-based suspensions, using polyelectrolytes, for the controlled shaping of functionally graded Al2O3/ZrO2 materials by means of electrophoretic deposition. Literature reports mainly focus on the relationship between the optimum amount of charging agent, the suspension stability and the electrophoretic deposition behavior. However, due to the complexity of physical and chemical phenomena involved, a general rule cannot be established. Aqueous suspensions of Al2O3 and ZrO2 powders, stabilized with a polyelectrolyte are well understood. Because aqueous suspensions present some limitations in the EPD process, due to the electrolysis of water at higher voltages, an organic environmentally friendly solvent with high dielectric constant is investigated. The minimum amount and type of charging agent and polyelectrolyte as well as their addition sequence is investigated by means of zeta potential measurements. The usefulness of the investigated suspensions is evaluated by shaping symmetrically graded alumina-zirconia discs, using a macroscopic model for the EPD process that allows to predict the final gradient in the sintered disc based on the powder characteristic, suspension characteristic and experimental EPD parameters. English Functionally Graded Materials VIII (FGM 2004) Functionally Graded Materials VIII(FGM 2004) 28 2004-07-14 783-788 常圧焼結Ce-TZPの微細構造および機械特性へのAl2O3添加の影響 Influence of Al2O3 Addition on the Microstructure and Mechanical Properties of Pressureless Sintered Ce-TZP Shuigen Huang, Lin Li, Jef Vleugels, Peiling Wang, Omer Van der Biest Shuigen Huang, Lin Li, Jef Vleugels, Peiling Wang, Omer Van der Biest  Mixtures of 12mol%CeO2-stabilised ZrO2 with 5 to 20wt% Al2O3 were prepared and densified through pressureless sintering in air at 1450deg.C for 1 to 4h. The influence of the Al2O3 content and sintering time on the phase constitution, microstructure and mechanical properties of the as-sintered composites were investigated. Fully dense Ce-TZP/Al2O3 ceramics with a good combination of hardness and fracture toughness can be obtained by pressureless sintering in air for only 1h. The addition of Al2O3 to Ce-TZP improves the mechanical properties and suppresses ZrO2 grain growth. The average ZrO2 grain size increases with increasing sintering time and decreasing Al2O3 content. This leads to an increase in toughness. An excellent fracture toughness of 14.3MPa*m**1/2 in combination with a Vickers hardness of 9.14GPa was obtained for 12mol% CeO2-TZP with 5wt%Al2O3, sintered for 4h. English