Development of Functionally Graded Materials by HIP
Yoshinari MIYAMOTO
Review Paper (Vol.6 No.1)
Development of Functionally Graded Materials by HIP |
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Yoshinari MIYAMOTO |
3 |
General Papers (Vol.6 No.1)
Calculation of Glass Transition Temperature of Na2O-B2O3-GeO2 Glass Based on the Sub-System Concept |
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Rikuo OTA and Takashi WAKASUGI |
9 |
Development of Carbonized TiO2-Woody Composites for Environmental Cleaning |
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Makoto DOI, Shiro SAKA, Hisashi MIYAFUJI and David A. I. GORING |
15 |
Vital Problems of Nanocomposite Structure and Possibilities of Their Modular Design |
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Phan Van AN and N. A. BULIENKOV |
22 |
Numerical Studies on Elastic Properties and Failure Mechanisms of Knit Fabric Composites |
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Nguyen K. CUONG, Zenichiro MAEKAWA and Hiroyuki HAMADA |
29 |
Effect of Molecular Weight on Fatigue Characteristics of Ultra-High Molecular Weight Polyethylene for Implant Material |
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Lei WANG, Mitsuo NINOMI, Takumi ENJITSU and Kei-ichi FUKUNAGA |
35 |
Theoretical and Numerical Investigation on Crack Identification Using Piezoelectric Material-Embedded Structures |
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Shanqing LI, Shiro KUBO, Takahide SAKAGAMI and Zhengxing LIU |
41 |
Porosity Effect on X-Ray Elastic Constants of Sintered Ceramics |
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Keisuke TANAKA, Yoshiaki AKINIWA and Toshimasa ITO |
49 |
Theoretical Prediction of Residual Stress Produced by Shot Peening and Experimental Verification for Carburized Steel |
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kazuyoshi OGAWA and Takashi ASANO |
55 |
Short comunication (Vol.6 No.1)
Improved Adsorption Potential of Sugi(Cryptomeria Japonica D. Don) Bark Carbonized after Steam-Treatment | |
Yasuji KURIMOTO, Lilibeth P. NOVICIO, Shuichi DOI and Masakazu AOYAMA |
63 |
Vol.6 No.1 ABSTRACT
Development of Functionally Graded Materials by HIP
Yoshinari MIYAMOTO
Abstract:Hot Isostatic Pressing(HIP) is a powerful tool to produce functionally graded materials (FGMs). The Partially Stabilized Zirconia(PSZ)/stainless steel, TiAl(¿/¿+Á), and W/Cu FGMs can combine incompatible functions of heat resistance and toughness in structural uses. In functional uses, the graded C/C composite for the heat receiver, the Ir/W/Ta emitter electrode for the thermionic converter, and one step formation of a graded thermoelectric conversion unit of SiGe with electrodes are developed using HIP. These recent developments of FGMs by HIP are reviewed. Key Words:Functionally graded materials, HIP, TiAl, Gas turbine blade, Diverter, Energy conversion system, Thermionic converter, Thermoelectric converter, SiGe
Calculation of Glass Transition Temperature of Na2O-B2O3-GeO2 Glass Based on the Sub-System Concept
Rikuo OTA and Takashi WAKASUGI
Abstract:Assuming the structural units in Na2O-B2O3-GeO2 glass being composed of structural units of the Na2O-B2O3 and Na2O-GeO2 systems(sub-systems), glass transition temperature Tg was estimated from the viscosity-temperature relationship based on the sub-system concept. The distribution of Na2O component among the B2O3 and GeO2 components is determined according to the assumption that Na2O activity in the Na2O-B2O3 system is equal to that in the Na2O-GeO2 system and the ratio of the Na2O activity coefficients in the Na2O-B2O3 system over that in the Na2O-GeO2 system is constant throughout the composition of the Na2O-B2O3-GeO2 system. The calculated and the observed Tg was in reasonable agreement within the experimental scatters. Key Words: Glass transition temperature, Viscosity, Na2O-B2O3-GeO2, Na2O-B2O3, Na2O-GeO2
Development of Carbonized TiO2-Woody Composites for Environmental Cleaning
Makoto DOI, Shiro SAKA, Hisashi MIYAFUJI and David A. I. GORING
Abstract:An effort was made to develop carbonized TiO2-woody composites which can effectively remove and decompose harmful air pollutants in environments. As an example of an air pollutant, formaldehyde (HCHO) was selected for evaluating the carbonized TiO2-woody composites. The composites were composed of carbonized wood as an adsorbent and the anatase-form of titanium dioxide (TiO2) as a photo-catalyst. They showed a much higher decomposing ability toward formaldehyde, when compared with the performance of non-composite controls composed of a simple physical mixture of carbonized wood and TiO2 granules. This indicates that synergetic effects existed in the carbonized TiO2-woody composites for photo-catalytic environmental cleaning. The topochemical mechanism inducing such synergetic effects is discussed in relation to the distribution of TiO2 granules in the composites. Key Words:Formaldehyde, Carbonized TiO2-woody composites, Photo-catalytic activity, Adsorptivity, Synergetic effect, Topochemistry
Vital Problems of Nanocomposite Structure and Possibilities of Their Modular Design
Phan Van AN and N. A. BULIENKOV
Abstract:A general approach to the study of the structure of all known forms of the solid state and of biological structures is possible on the basis of the concept gmoduleh that is more general and unambiguous than gthe latticeh. The potentialities of modular design for the deliberate selection of structural components and the estimation of the opportunities of their self-organization due to formation of perfect coherent boundaries between their regularly oriented crystallites in nanocomposites were shown by the examples of two-dimensional Penrose mosaics and three-dimensional biomimetic composite amorphous-Al2O3 - hydroxyapatite - collagen - gbound waterh. Key Words:Module, Modular design, Biomimetic nanocomposite, Corundum, Hydroxyapatite, Collagen, gBound waterh, Hydrogen bond.
Numerical Studies on Elastic Properties and Failure Mechanisms of Knit Fabric Composites
Nguyen K. CUONG, Zenichiro MAEKAWA and Hiroyuki HAMADA
Abstract:This paper describes elastic behavior and failure mechanisms of plain-knit fabric composites. A single-ply glass-fiber knit fabric impregnated with epoxy resin@was used to fabricate composite specimens. Tensile tests were then carried out in two directions: the wale and the course directions of the fabric. During the test, the fracture behavior of the composite specimen was identified by a video camera which caught the loop images from the beginning to their failure. Tensile properties were also experimentally determined. Furthermore, a three-Dimensional (3-D) finite element model of a knitted loop was proposed for prediction of tensile moduli as well as failure mechanisms of the plain-knit fabric composite. The validation of the loop model was estimated by comparison of the experimental results with the predicted ones. Key Words:Knitted loop, Plain knit fabric composites, 3-D numerical model, Failure mechanisms
Lei WANG, Mitsuo NINOMI, Takumi ENJITSU and Kei-ichi FUKUNAGA
Abstract:In order to investigate the effect of molecular weight on fatigue characteristics in the ultra-high molecular weight polyethylene (UHMWPE), tension-tension fatigue tests of notched specimens were carried out in the present study. The effects of testing parameters were investigated and fractography was also discussed. The fatigue strength does not increase with increasing molecular weight. The fatigue strength might be influenced by the high degree of crystallinity in spite of the decreased tie molecular density. Almost no effect of frequency on the number of cycles to failure can be observed. However, the higher the frequency is, the higher the crack tip temperature. At high stress ratio, number of stress cycles to failure (S-N) curves shift to the side of high number cycles to failure. Key Words: Molecular weight, Fatigue, Ultra-high molecular weight polyethylene, Frequency, Stress ratio
Shanqing LI, Shiro KUBO, Takahide SAKAGAMI and Zhengxing LIU
Abstract:This work presents theoretical and numerical investigation on crack identification using piezoelectric materials embedded in structures. At first, a crack estimation model was designed by using piezoelectric materials. A simplified analysis was employed by separating the solving procedure for this model to two steps: fracture mechanics analysis and piezoelectric analysis. Two hypotheses named as the MLTNM hypothesis and the constant strain hypothesis were adopted. By means of these two analysis steps, the effect of the crack on the potential distribution can be obtained. Then taking use of a finite element program, comparisons between theoretical and numerical results were examined. The theory was also used to find the relationship between the crack parameters and the potential distribution. Numerical simulations of crack identification were made. The applicability of the use of piezoelectric materials to crack identification was demonstrated. Key Words:Piezoelectric material, Intelligent structure, Crack, Nondestructive testing
Porosity Effect on X-Ray Elastic Constants of Sintered Ceramics
Keisuke TANAKA, Yoshiaki AKINIWA and Toshimasa ITO
Abstract:The effect of porosity on the elastic constants for X-ray stress analysis in sintered alumina was analyzed on the basis of three micromechanical models: Reuss' model, Voigt's model, and the self-consistent model (SC model). The mechanical Young's modulus decreased with decreasing bulk density or increasing porosity, while Poisson's ratio was nearly constant. The experimental value of X-ray elastic constant, (=Young's modulus, =Poisson's ratio), decreased with decreasing bulk density or increasing porosity. SC model gave the best estimation for the effect of bulk density on the X-ray elastic constants. The prediction based on SC model requires the mechanical elastic constants of sintered alumina as a composite and the X-ray elastic constants of diffracting phases. It is not necessary to know the properties of secondary phases. When the mechanical elastic constants of ceramics are not known, the bulk density can be used to estimate the mechanical elastic constants, and then the X-ray elastic constants. Key Words:Stress measurement, X-Ray method, Elastic constants, Sintered alumina, Voigt's model, Reuss' model, Self-consistent model, Porosity effect
kazuyoshi OGAWA and Takashi ASANO
Abstract:Simplified theoretical formulae based on shot peening parameters and materials properties have been de-veloped to predict the maximum and the peak depth of the compressive residual stress produced by shot peening. These formulae are based on the motion equation for a shot and the analytical model proposed by Li, who utilized the Hertz theory of elastic contact and a simplified elasto-plastic theory. Experimental verifications were carried out under various shot peening conditions. Shots were made of cast steel, fused Zirconia, and glass, each having its own range in diameter. Actual residual stress distributions were measured by the X-ray diffraction method. The maximum and peak depth of the compressive residual stress predicted by the proposed formulae agreed well with the experimental values in a wide variety of shot peening conditions. Key Words:Residual stress, Shot peening, Stress analysis, Hertz theory, Carburizing, Steel, Zirconia, Glass