材料
Online ISSN : 1880-7488
Print ISSN : 0514-5163
ISSN-L : 0514-5163
52 巻 , 10 号
選択された号の論文の20件中1~20を表示しています
  • 塚本 忠和, 川崎 元夫, 山根 秀樹
    2003 年 52 巻 10 号 p. 1147-1154
    発行日: 2003/10/15
    公開日: 2009/06/03
    ジャーナル フリー
    Silica/poly (vinyl alcohol) (PVA) layers with various PVA ratios were coated on nylon 6 films by sol-gel method. Damage of Silica/PVA layer on the nylon 6 film caused by elongation was examined by an atomic force microscope (AFM) and scanning electron microscope (SEM) observations and measurements of water vapor permeation rate. At 1% elongational strain, pure silica layer no longer follows the deformation of nylon film and the linear cracks perpendicular to the stretching direction were produced. Consequently water vapor permeability of silica coated films increased drastically. However, critical elongational strain at which linear cracks were produced increased with PVA ratio in silica/PVA layer and only mild deterioration of barrier property was observed. Such durability of silica/PVA layer to the elongational strain is due to the flexibility of silica/PVA layer which can follow the deformation of nylon film. Further PVA seems to fill the micropores of silica prepared by sol-gel method.
  • 竹内 信行, 阿比留 祐二, 石田 信伍
    2003 年 52 巻 10 号 p. 1155-1159
    発行日: 2003/10/15
    公開日: 2009/06/03
    ジャーナル フリー
    Effect of firing atmosphere on the electrical properties of La-doped and La-Mn-codoped BaTiO3 ceramics was studied by combining diffuse reflectance measurements and electron spin resonance (ESR) spectroscopy The room temperature resistivity of 0.2mo%La-0.05mol%Mn-codped and 0.3mol%La-0.05mol%Mn-codoped samples fired in air was lower than that of La-doped samples. The result attributed to promotion of grain growth by addition of Mn. The room temperature resistivity of the samples fired in Ar was independent on the concentration of La and Mn, and was inclined to be lower than that of samples fired in air. It was assumed that oxygen vacancies were formed in the samples fired in Ar and resulted in generation of conduction electrons. All samples prepared in this study were semiconductive and the behavior of absorbance in the range of near infra-red agreed with the relationship between electron conductivity and La concentration. The result suggested that the intensity of absorbance was due to the concentration of conduction electrons. The decrease of positive temperature coefficient of resistivity of La-Mn-codoped samples fired in Ar was assumed to cause by decrease of chemisorbed oxygen in the grain boundary region. The line width of the ESR signal of Mn2+ observed in the sample fired in Ar was larger than that in the samples fired in air. The result indicated that part of Mn3+ in the grain boundary region was reduced to Mn2+ during firing in Ar.
  • 中村 暢伴, 荻 博次, 市坪 哲, 平尾 雅彦, 辰巳 夏生, 今井 貴浩, 中幡 英章
    2003 年 52 巻 10 号 p. 1160-1165
    発行日: 2003/10/15
    公開日: 2009/06/03
    ジャーナル フリー
    This paper studies the anisotropic elastic constants of a CVD polycrystalline diamond film using acoustic spectroscopy and micromechanics modeling. Many films exhibit elastic anisotropy between the film-growth direction and inplane direction and possess five independent elastic constants; they are C11, C33, C12, C13 and C44 when the x3 axis is along the film-growth direction. Combination of resonance ultrasound spectroscopy (RUS) and electromagnetic acoustic resonance (EMAR) deduces the four independent elastic constants among them, including C44 and C66, with which the elastic anisotropy is discussed. We found 5-10% anisotropy between them and considerably small elastic constants compared with an isotropic polycrystalline diamond. We attribute the anisotropy and small elastic constants of the CVD diamond film to local incomplete cohesion. This view is supported by a micromechanics calculation.
  • 小林 眞造, 上杉 泰司, 三浦 精
    2003 年 52 巻 10 号 p. 1166-1173
    発行日: 2003/10/15
    公開日: 2009/06/03
    ジャーナル フリー
    The study described in this paper concerns the microscopic deformation and fracture, such as micro-cracks, chipping and striation produced by repeated indentation loading. The repeated indentations with a diamond Vickers indenter were made onto the same point on the (0001) and (1010) faces of the Sapphire (Al2O3) single crystals under two kinds of indentation speed of 10 and 100 (cycles/min).
    Microscopic observations of the indented surface were made to evaluate the appearances of the radial and lateral cracks, and to examine the number of loading cycles needed to originate chipping. The effects of the indenter azimuth and crystal face on the patterns of the fracture and deformation were also examined. The conclusions obtained from the experimental results are summarized as follows:
    (1) The fracture on both the (0001) and (1010) faces starts with an origination of radial cracks, and with an increase in number of loading cycles, lateral cracks, chippings and striations are produced.
    (2) Relation between indentation load and number of cycles to chipping in Sapphire is correspondent to that between stress and number of cycles to fracture obtained under fatigue tests for metallic materials.
    (3) Deformations, and fracture damage on the (0001) face under 0° indentation are greater than those under 45° indentation. On the contrary, on the (1010) face, those are greater in the case of 45° indentation.
    (4) Twinnings are observed on the (1010) face under the load of greater than 3.0N.
    (5) The pile-up of the material and small plastic deformations of the block pattern are formed around an indent on the (1010) face.
  • 李 炎, 阿部 武治, 多田 直哉
    2003 年 52 巻 10 号 p. 1174-1179
    発行日: 2003/10/15
    公開日: 2009/06/03
    ジャーナル フリー
    Change in the surface morphology during tensile plastic deformation of polycrystalline titanium with grain size of about 30μm is consecutively observed and measured by the scanning probe microscope. The results show that the surface deformation is mainly due to slip for the plastic strain less than 0.1. After that, a large amount of twins are formed and the second slip system becomes active, and accordingly the surface roughness increases. The roughness, the maximum height difference, and the averaged slope angle of the microscope surface profile increase with the applied tensile strain. The step height of the first slip lines increases, while the spacing between the slip lines decreases with the applied strain. Furthermore, the ratio of the step height to the spacing increases almost linearly with the applied strain. The angle between the slip lines and the load axis decreases due to the rotation of the crystal grain with the applied strain.
  • 松本 仁, 石井 信行
    2003 年 52 巻 10 号 p. 1180-1185
    発行日: 2003/10/15
    公開日: 2009/06/03
    ジャーナル フリー
    In order to reveal effects of rapid solidification on a shape memory NiTi alloy, ribbons of NiTi rich in titanium are prepared by a single roll method and experiments of X-ray diffraction and thermal analysis are performed to characterize the rapidly-solidified NiTi ribbon.
    The ribbon has the same crystal structure as that of furnace-cooled NiTi and the surface of the ribbon shows the markedly prefered ‹100› orientation in the high-temperature phase. The lattice constant of the high-temperature phase tends to decrease with increasing composition of titanium and the Ti2Ni phase precipitates at compositions above 53 at. % titanium, of which the behaviors are almost unchanged even by annealing up to 800°C. The shift of the transformation temperature caused by rapid solidification is small, though the transformation behavior of the NiTi ribbon and its recovery process due to annealing are complicated. The prepared NiTi ribbon shows a shape memory, even without a heat treatment. Therefore, the transformation is not practically influenced by the rapid solidification. It is concluded that the ribbon available for the shape memory material can be directly made from the melt by the single roll method.
  • 徳田 正孝, 稲葉 忠司, 倉掛 暁, 生島 誠士, 陳 陽
    2003 年 52 巻 10 号 p. 1186-1191
    発行日: 2003/10/15
    公開日: 2009/06/03
    ジャーナル フリー
    The fine grain super-plasticity under the combined loading conditions was investigated experimentally by applying the combined loads of axial force and torque to the thin-walled tube specimen of 5083 aluminum alloy. Moreover, a set of constitutive equations for the fine-grained super-plastic materials was proposed on the basis of these experimental results and the classical (mathematical, phenomenological) theory of plasticity using the potential function. Here a new potential function was proposed by incorporating the second and third invariants of stress deviator. The proposed constitutive equations could predict well the mechanical behaviors of 5083Al alloy subjected to the combined loading conditions under the wide ranges of temperature and strain rate.
  • 井上 達雄, 森本 吉浩
    2003 年 52 巻 10 号 p. 1192-1197
    発行日: 2003/10/15
    公開日: 2009/06/03
    ジャーナル フリー
    Jominy bar test is popularly used to evaluate hardenability of steels. Thermal and phase transformation stresses and strains are induced in the specimen quenched from an end, the effect of which is not taken into consideration in usual cases. Simulation based on metallo-thermo-mechanics is carried out by use of developed code “HEARTS” to estimate the induced martensite distribution as well as temperature and stresses during and after the test, so to identify the Jominy distance. Here, the material parameters necessary for the simulation are employed from the material database “MATEQ” developed by the Subcommittee on Material Database, the Society of Materials Science, Japan (JSMS). The results of simulation on the Jominy distance depending on chemical compositions and other material characteristics are discussed compared with experimental data for several steels, and the effect of the stresses are evaluated. Thus determined data of Jominy distane are also compared with the ideal critical diameter being another effective parameter to evaluate hardenability of steels.
  • 大塚 貴之, 井上 達雄
    2003 年 52 巻 10 号 p. 1198-1203
    発行日: 2003/10/15
    公開日: 2009/06/03
    ジャーナル フリー
    Four-point bending tests are employed to identify the transformation plasticity coefficient, which plays an important role in the inelastic constitutive equation applied to more sophisticated heat treatment process simulation. In this paper, a slender bar type specimen is chosen for the bending tests to identify the transformation plasticity coefficient during pearlite reaction, which is also possible for martensite transformation under high cooling rate when using a pipe specimen. An austenized steel bar is cooled down in the air by free convection under four bending load. When the temperature reaches the pearlite start point, so remarkable deflection progresses due to the effect of transformation plasticity until pearlite finish temperature. The TP strain is easily evaluated from the data of the deflection as a function of applied deviatric stress, which gives the value of the coefficient. Some data are taken under different applied stress by choosing bars with 5 or 3mm in diameter and compared with data by other methods in references. The obtained data of coefficient of transformation plasticity will be piled up in the materials database MATEQ (MATerial database for Quenching process simulation) now released by the Society of Material Science, Japan (JSMS) available for heat treatment simulation.
  • 北條 浩, 山田 明, 猿木 勝司
    2003 年 52 巻 10 号 p. 1204-1210
    発行日: 2003/10/15
    公開日: 2009/06/03
    ジャーナル フリー
    On three types of tufftrided spheroidal and flaky graphite cast irons, the fatigue limit diagrams which are used as the basis when estimating the fatigue strength of components were constructed. The major results are shown in below.
    (1) In the case of smooth specimen of spheroidal graphite cast irons FCD700 and FCD500, the effect of tufftriding could not be correctly estimated because it was influenced in the casting defects. On the other hand, in the case of notched specimen, there was no example of fracture induced by the casting defects, then the improvement of fatigue limit could be correctly estimated.
    In this case, the fatigue limit of FCD700 was considerably improved with 20%, and that of FCD500 was remarkably improved with 34%. It is considered that the notch reduced the probability with the casting defect which exists in the fracture domain and induced the proper effect of tufftriding.
    (2) The fatigue limits of tufftrided FCD700 and FCD500 were accurately predicted on basis of 3-parameters, that is to say, the compressive residual stress, Vickers hardness of subsurface pearlitic phase and maximum graphite diameter.
    (3) In the case of flaky graphite cast iron FC230, the fatigue limits were improved with 17% on smooth specimen, and 14% on notched specimen respectively. The depth of compressive residual stress distribution induced by tufftriding was shallow compared with the size of flaky graphite on both specimen. So there was no great difference on the improvement of fatigue limit between the two types of specimen.
    (4) The fatigue limit of tufftrided FC230 was accurately estimated from the fatigue limit diagram which was added the compressive residual stress at the distance of flaky graphite length (100μm) from notch root as mean stress to the fatigue limit diagram of non-tufftrided FC230.
  • 京野 純郎, 新谷 紀雄
    2003 年 52 巻 10 号 p. 1211-1216
    発行日: 2003/10/15
    公開日: 2009/06/03
    ジャーナル フリー
    In austenitic stainless steels creep cavities nucleate at grain bourdaries by long time use at high temperatures. These creep cavities grow along grain bounrdaries, form grain boundary cracks by linking up each other, and cause premature and low ductility fracture. Therefore long time creep rupture life and ductilites chiefly depend upon the behavior of nucleation and growth of creep cavities. If the growth of creep cavities could be suppressed, creep rupture life and ductilites should be improved remarkably. The present work is intended to propose a self-healing process for the cavitation by utilization of thin filmy precipitation at creep cavity surface and improve the creep rupture properties by the self-healing process. In ordinary austenitic stainless steels, sulfur is contained as impurity and segregates to creep cavity surface because of its high surface activity. It is thought that a stable compound can precipitate at creep cavity surface if the sulfur is completely removed. Therefore in order to remove sulfur completely and precipitate a stable compound at creep cavity surface, a modified 304 stainless steel added with cerium, titanium, boron and nitrogen was laboratory-melted. The modified steel showed high rupture strength and high rupture ductilities, and it was confirmed that boronnitride precipitates at creep cavity surface in the steel. It was thought that the boronnitride at creep cavity surface suppresses the creep cavity growth and improves creep rupture properties by the self-healing effect on creep cavities.
  • 元屋敷 靖子, 菅田 淳, 植松 美彦, 城野 政弘
    2003 年 52 巻 10 号 p. 1217-1224
    発行日: 2003/10/15
    公開日: 2009/06/03
    ジャーナル フリー
    The 2-dimensional Discrete Dislocation Dynamics (DDD) analysis was carried out in order to elucidate the stress distribution and dislocation behavior around stationary and growing fatigue crack tips. The forward slips during loading and the reverse slips during unloading were emerged near the crack tip. The high compressive stress, which caused the reverse slips during unloading, was induced by many positive dislocations piled up remote from the crack tip. The model taking into account the crack growth was suggested in order to investigate the effect of the dislocations left in the crack wake as a result of crack growth on the stress distribution and the dislocation behavior near the crack tip. In the growing fatigue crack, the compressive stress was produced by the reaction forces of the dislocations left in the crack wake in addition to the piled up positive dislocations. And it was confirmed that the cyclic plastic deformation around the fatigue crack tip was well simulated by means of DDD.
  • 坂井田 喜久, 田中 啓介, 秋庭 義明, 沢木 洋三
    2003 年 52 巻 10 号 p. 1225-1230
    発行日: 2003/10/15
    公開日: 2009/06/03
    ジャーナル フリー
    In order to measure loading and residual stresses near the notch tip in Al2O3 ceramics using a micro X-ray beam of SPring 8 (super Photon ring-8GeV), X-ray elastic constants were first determined experimentally. Mechanical elastic constants of the used material were E=372GPa and v=0.23. The diffraction from Al2O3 2.0.14 plane by 8keV radiation was used for X-ray stress measurement. The 2θ-sin2ψ diagrams under several applied stresses were measured. From the relationship between both slope, M, and intercept 2θψ=0 of 2θ-sin2ψ diagram and applied stress, X-ray elastic constants were determined to be Ex=416GPa and vx=0.20. Next, the local stress measurement in the irradiated area with 100×100μm2 was examined in comparison to that with 100×500μm2. Loading stress in a local area with 100×100μm2 can be measured by the sin2ψ method. Finally, the local loading stresses, σy (x), near the V-notch tip under a four-point bending load were measured across the minimum ligament of SEVNB (Single-Edge-V-notched Beam) specimen by scanning the micro X-ray beam along the x-axis. The stress concentration near the notch root was first difficult to be measured directly because of the grinding residual stress by V-notch machining. After annealing, the stress concentration was detected by changing the irradiated area of X-ray from 100×100 to 50×50μm2. The degradation of the measured stresses in the notch tip was caused by the X-ray irradiation to the notch, and almost agreed with the results of a finite element analysis. The local stress and residual stresses were found to be measured by the sin2ψ method using synchrotron micro X-ray beam with a spatial resolution of about 50μm.
  • 松英 達也, 英 崇夫, 池内 保一, 日下 一也
    2003 年 52 巻 10 号 p. 1231-1236
    発行日: 2003/10/15
    公開日: 2009/06/03
    ジャーナル フリー
    Residual stress in a coating film is influenced by an undercoated layer in a multi-layered film system. The present study investigates residual stress as well as crystal texture in two- and three-layered films, i. e., Cu/TiN film, SiO2/Cu film and SiO2/Cu/TiN film deposited on glass substrates. TiN film was first deposited by arc ion plating on the substrate as an undercoated layer and then Cu and SiO2 films were deposited on it by plasma coating. The crystal structure and the residual stress in the deposited multi-layered film were investigated by atomic force microscope (AFM) and X-ray diffraction as a function of film thickness of TiN layer.
    It was found that the SiO2 film was amorphous and both the Cu film and the TiN film had a strong {111} orientation. The two-exposure method was used to evaluate residual stress in the Cu and the TiN films by measuring lattice strains in two directions determined by crystal orientation. The Cu layer in Cu/TiN film had tensile residual stresses of 180-240MPa, and the Cu layer in SiO2/Cu/TiN film had slightly larger tensile residual stresses of 210-260MPa. These stresses in both films increased with the film thickness of the undercoated TiN layer. The TiN layer of Cu/TiN and SiO2/Cu/TiN had also tensile residual stress of 300 and 330MPa, respectively.
  • 田中 啓介, 秋庭 義明, 水野 賢一, 白木原 香織
    2003 年 52 巻 10 号 p. 1237-1244
    発行日: 2003/10/15
    公開日: 2009/06/03
    ジャーナル フリー
    An X-ray method is proposed to measure the stress in a specimen made of silicon single crystal wafer which has the [001] direction perpendicular to the surface. In an X-ray diffractometer with parallel beam optics, X-ray profiles were recorded by a scintillation counter while the specimen was oscillated. The X-ray measurement conditions were first determined, and then the method was successfully applied to measure the loading stress in a silicon single specimen subjected to four-point bending. The oscillation of the specimen between ±1 to 2deg during recording is necessary to determine the peak position. The miss-setting of 25μm does not influence the measured stress value. The uniaxial stress was applied in [110] direction (longitudinal direction with ψ=0deg) of the specimen and three stress components, σ11, σ22 and σ12, were determined from the measurement of strains in three directions, ψ=0, 90, and 45deg. From the diffractions of 115 and 333 for two directions ψ=0 and 90deg, the stresses, σ11 and σ22, were determined by the 2θ-sin2ψ method. The shear stress component, σ12, was determined from the strain measurements of two directions, ψ=26.565 and 63.435deg by using the diffractions of 004 and 133. The measured stress of σ11 is 102% of the applied, stress and the two other Components, σ22 and σ12, were nearly zero. The uniaxial state of stresses in plate under four point bending was confirmed as predicted by the finite element method.
  • 合田 公一, 浅井 隆, 山根 達也
    2003 年 52 巻 10 号 p. 1245-1252
    発行日: 2003/10/15
    公開日: 2009/06/03
    ジャーナル フリー
    It is expected that environment-friendly biodegradable composites reinforced by high strength natural fibers are widely used for industrial applications, preferably in place of glass fiber reinforced plastics (GFRP). The purpose of this study is thus to publish useful information on fabrication process, optimum forming pressure and mechanical properties of ramie fiber reinforced biodegradable resin matrix composites. It was found out that (1) a pre-forming method is effective in arranging ramie strings unidirectionally and exactly, and therefore can increase dramatically the composite strength, and (2) an optimum forming pressure for increasing appropriately tensile strength and Young's modulus is in the range of 13.1 to 19.6MPa. We further investigated the effect of chemical treatments on mechanical properties of treated ramie fiber reinforced biodegradable resin composites. The results showed that alkali-treated fiber composite was unchanged in strength as compared to untreated fiber composite, while the treated fiber composite was well improved in Young's modulus, 30% larger than that of untreated fiber composite.
  • 倉鋪 憲, 倪 慶清, 岩本 正治
    2003 年 52 巻 10 号 p. 1253-1257
    発行日: 2003/10/15
    公開日: 2009/06/03
    ジャーナル フリー
    It may be difficult to make quantitative damage evaluation for FRP composites by means of traditional methods due to the occurrence of various damages and their interactions. On the other hand, for GFRPs under cyclic loading, the temperature rise was observed and there existed a good relationship between fatigue damage and temperature rise. Particularly it was possible to quantitatively evaluate the fatigue damage at the middle term of lifetime for GFRPs. However, there are a lot of factors that may affect the temperature rise in GFRP composites, and the property of matrix and fiber content are two main parameters. Thus, in this paper, the fatigue temperature rise curve for GFRP composites of continuous glass fiber reinforced CP-resin was obtained. Two kinds of matrix resin, one has much better elongation property than the another, were used and several fiber contents were prepared for the specimens. Then the effects of both matrix resin and fiber content on fatigue temperature rise curve were examined. As a result, it was found that the fiber content had much larger influence than the property of matrix resin on fatigue temperature rise. It was also found that the proposed evaluation method would be especially effective for the GFRP composites with high fiber content and brittle matrix.
  • 松田 哲也, 大野 信忠, 田中 宏紀, 清水 利弘
    2003 年 52 巻 10 号 p. 1258-1264
    発行日: 2003/10/15
    公開日: 2009/06/03
    ジャーナル フリー
    In this work, the effect of transverse fiber distribution on the elastic-viscoplastic behavior of long fiber-reinforced laminates is studied using a homogenization theory. To this end, a basic cell with random fiber distribution is arranged point-symmetrically with respect to the cell boundary facet centers. The basic cell is also arranged Y-periodically. It is demonstrated that the point-symmetric arrangement enhances the randomness of fiber distribution than the Y-periodic arrangement. Then, by assuming the point-symmetry based fiber distribution as the transverse fiber array in laminae, the in-plane elastic-viscoplastic deformation of CFRP laminates is analyzed using the homogenization theory of nonlinear time-dependent composites. Comparative analysis is further performed by assuming the perfectly periodic, hexagonal fiber distribution in laminae. It is thus shown that the transverse randomness of fiber distribution has negligible influence on the macroscopic elastic-viscoplastic behavior of laminates, whereas the microscopic distribution of stress in laminae is markedly affected by the fiber distribution. It is also shown that the results of analysis agree very well with the corresponding experimental results.
  • 岡 二三生, 日置 和昭, 小高 猛司, 山田 裕久
    2003 年 52 巻 10 号 p. 1265-1270
    発行日: 2003/10/15
    公開日: 2009/06/03
    ジャーナル フリー
    Sand compaction pile method is an effective soil improvement technique to prevent the liquefaction of loose sandy ground. Since the current design method of the sand compaction pile method is only incorporating the effect of the densification of sand due to compaction, the seismic design for this method has been reexamined after the 1995 Hyogoken Nambu Earthquake. However, the characteristics of compacted sand containing fine contents have not completely been clarified; it is difficult to incorporate all the complicated improvement effects to the current design code. In light of the recent trend of performance design, the dynamic numerical analyses by the finite element method have spread in practice. The soil water coupled liquefaction analysis, among many existing numerical analyses, can be particularly expected to evaluate the complicated improvement effects of compacted sand. Oka et al. have proposed the effective stress based liquefaction analysis using an elasto-plastic constitutive model for sand based on nonlinear kinematic hardening rule. In the present study, in order to explain the compaction effect of sand containing the fine contents, we have noted the relation between the parameters used in the elasto-plastic constitutive model and the state index of sand, Is. A series of undrained traixial compression tests of sand were conducted under the conditions that reproduce both the effective stress state and void ratio before and after compaction. We also simulated the triaxial test results by using the elasto-plastic constitutive model. It is found that the quasi overconsolidation ratio, OCR*, is correlated to the state index of sand and is one of the key parameters to evaluate the compaction effect of sand.
  • 大津 宏康
    2003 年 52 巻 10 号 p. 1271-1277
    発行日: 2003/10/15
    公開日: 2009/06/03
    ジャーナル フリー
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