材料
Online ISSN : 1880-7488
Print ISSN : 0514-5163
ISSN-L : 0514-5163
49 巻 , 7 号
選択された号の論文の18件中1~18を表示しています
  • 秋田 貢一, 坂田 創, 柏谷 賢治, 三沢 啓志
    2000 年 49 巻 7 号 p. 722-728
    発行日: 2000/07/15
    公開日: 2009/06/03
    ジャーナル フリー
    Fatigue crack growth tests were carried out using a high manganese austenitic cast steel under constant amplitude loading. Average crystal grain sizes of the material are 200 micro-meters and 1000 micro-meters. For this material, threshold stress intensity factor range (ΔKth) is about 8MPa√m which is quite large as compared to the ΔKth of general structural steels. The crack growth rate is lower than the general structural steels especially in the lower ΔK region. The reasons of this behaviour are crack closure due to bridging and fretting oxide, decreasing of the stress concentration near the crack tip due to secondary crack and slip on crystal plane. X-ray fractography can be applied to the fatigue fracture surface of the material which has large grain by using oscillation of X-ray beam and in-plane oscillation on the fracture surface. The half-value breadth of the diffraction profile on the fracture surface increases with increase in the effective stress intensity factor range. The relationship between the half-value breadth and the effective stress intensity factor range was represented by a narrow band regardless of the stress ratio.Therefore, the effective stress intensity factor range can be estimated from this relation in fractured surface of actual components.
  • 鷹合 滋樹, 佐々木 敏彦, 秋田 貢一, 吉岡 靖夫, 広瀬 幸雄
    2000 年 49 巻 7 号 p. 729-734
    発行日: 2000/07/15
    公開日: 2009/06/03
    ジャーナル フリー
    We used X-ray diffraction method using Synchrotron radiation (SR) for solving residual stress in composite material. Diffraction planes with arbitrary diffraction angle were measured. Moreover, there is a characteristic that the different diffraction planes at same 2θ angle were obtained using SR with different wave length. In this study, effects of penetration depth on an X-ray parameter of the composite material were examined. First of all, the X-ray elastic constant of the single-phase body (PXEC) was measured for the evaluation of the phase stress. Next, the elastic deformation behavior of phase stress in the matrix phase was evaluated, and the influence of the second phase particle was investigated. Residual phase stress of each phase in the fracture surface is measured as an application example for the X-ray Fractography. The relation between the stress intensity factor and TiN volume fraction was examined.Trying to fracture toughness test in composite material, we discussed influence of fracture toughness value on residual stress. Deformation behavior of softer matrix phase was controlled by hard second phase particle under macroscopic tensile stress. It was found that residual stresses in the fracture surface were relaxed on the surface.Furthermore, there is the correlation between the stress intensity factor at the fracture and the phase stress in the matrix phase.
  • 松英 達也, 英 崇夫, 池内 保一, 三木 靖浩, 米谷 英治
    2000 年 49 巻 7 号 p. 735-741
    発行日: 2000/07/15
    公開日: 2009/06/03
    ジャーナル フリー
    The structure and residual stresses of TiN films deposited onto substrate of spring steel by an arc ion plating were investigated by X-ray diffraction. The films exhibited high {111} orientation. Residual stresses in the films were evaluated by the two-exposure method to obtain lattice strains for 222 diffraction at ψ=0° and 70.5° with CuKα radiation. The results revealed very high compressive residual stresses of -7.1 to -6.3GPa which are one order larger than the thermal residual stress expected from the thermal strain mismatch between the film and the substrate. These residual stresses decreased with increasing annealing temperature and annealing time, and finally reached a level of the thermal residual stress after annealing at temperatures above 1073K. Vickers micro hardness tests of TiN films revealed high hardness (HV 950-2360) whose value depended on annealing treatments. No residual stress was observed in the substrate interface in an as-deposited state. Tensile residual stress was developed after the annealing above 1273K. Vickers hardness of steel substrate was about 170HV for the annealing below 1073K. After annealing at 1273K, the hardness increased to about 300HV due to the structural transformation.
    The ratio of nitrogen to titanium (N/Ti) was observed by the X-ray photoelectron spectroscopy (XPS) before and after annealing treatments. The results of the XPS analysis showed that the initial value of N/Ti was about 0.87 in the as-deposited TiN films and that the ratio of N/Ti did not change after annealing at temperatures below 1073K, and gradually decreased to 0.80 by annealing above 1073K.
  • 秋庭 義明, 田中 啓介, 皆川 宣明, 森井 幸生
    2000 年 49 巻 7 号 p. 742-747
    発行日: 2000/07/15
    公開日: 2009/06/03
    ジャーナル フリー
    The neutron diffraction method was used to measure the residual stress in ceramic composites of alumina mixed with various volume fractions of zirconia, Al2O3/ZrO2, and of silicon carbide, Al2O3/SiC. The thermal residual stresses of the zirconia phase, alumina phase and silicon carbide phase were measured as a function of the volume fraction of constituent phase. The phase stresses were determined from the neutron diffractions of ZrO2202, Al2O3113, Al2O3116, SiC220 and SiC311. In Al2O3/ZrO2 composites, the residual stress in the alumina phase was compression and that in the zirconia phase was tension. On the other hand, in Al2O3/SiC composites, the residual stress in the alumina phase was tension, and increased linearly with the silicon carbide volume fraction. The residual stresses were introduced by the mismatch of the coefficient of thermal expansion. The change of the residual stress with volume fraction of constituent phase agreed well with the theoretical prediction based on Eshelby's inclusion model.
  • 秋田 貢一, 吉岡 靖夫, 鈴木 裕士, 佐々木 敏彦
    2000 年 49 巻 7 号 p. 748-753
    発行日: 2000/07/15
    公開日: 2009/06/03
    ジャーナル フリー
    The residual stress distributions just beneath the fatigue fracture surface were measured using synchrotron radiation with three different wavelengths, i.e., three different penetration depths. The residual stress distributions were estimated from three kinds of diffraction data by the following process. First, a temporary residualstress distribution in the depth direction is assumed. Theoretical 2θ-sin2Ψ diagrams for each wavelength, where each has a different penetration depth, are calculated by the cosΨ method developed by one of the authors. The sum total of the differences between the theoretical and experimental values of the diffraction angle in 2θ-sin2Ψ diagrams is calculated. This total value is minimized by changing the assumed stress distribution by the quasi-Newton optimization method. Finally, optimized 2θ-sin2Ψ diagrams for each penetration depth and detailed stress distribution are determined. The true surface residual stress is obtained from this stress distribution.
    No effect of load ratio R(=Pmin/Pmax) on the residual stresses of the fatigue fracture surfaces in low-carbon steels was observed when the sin2Ψ method was used for stress measurement. However, the residual stresses became higher with increasing R when these were measured by the proposed method. On the basis of this, the stress intensity factor range, ΔK, can be estimated from the residual stress on the fatigue fracture surface.
  • 大谷 眞一, 小島 玲子, 萩原 芳彦
    2000 年 49 巻 7 号 p. 754-759
    発行日: 2000/07/15
    公開日: 2009/06/03
    ジャーナル フリー
    The purpose of this investigation is to clarify the behavior of the compressive residual stress induced by shot peening treatment during fatigue process. Fatigue tests on shot-peened specimen were carried out by using a cantilever type rotary bending fatigue test machine. The distributions of actual stress on specimen circumference at the maximum tensile applied load were dynamically measured by the x-ray stress analysis based on the single exposure technique without stopping fatigue test. The distributions of residual stress were also measured under unloading by the same way.
    As the results, the actual stress at every position on specimen circumference was roughly the same value as the algebraic sum of the compressive residual stress and the maximum tensile applied stress until crack initiation.However, after a macro crack was appeared in the surface of specimen, the circumferential distribution of actual stress was showed V-shape at crack position. The actual stress at the bottom of V-shaped distribution was the same value as the compressive residual stress when crack length reached greater in size than a width of x-ray irradiation area. It was confirmed that change of actual stress distribution on specimen circumference could indicate the positions of crack initiation. Meanwhile, the average compressive residual stress on specimen circumference was relaxed drastically in initial stage of fatigue life, thereafter it declined barely with increasing a number of stress cycles until the specimen was ruptured. However, circumferential distribution of residual stress remained constant even then there were macro cracks in the peened surface. It was confirmed that observation of the average residual stress and the circumferential distribution of residual stress could not detect the fatigue damage in the peened surface.
  • 増田 秀夫, 鷹合 滋樹, 比良 光善, 広瀬 幸雄
    2000 年 49 巻 7 号 p. 760-765
    発行日: 2000/07/15
    公開日: 2009/06/03
    ジャーナル フリー
    Ni-Co-P/α-Si3N4 composite plating excels in wear-and corrosion resistance. It is important to evaluate the residual stress due to the misfit of mechanical and physical properties between plating and substrate during the manufacturing and industrial using. However, in the case of plating specimen which have stress gradient, the sin2Ψ method is not adequate to use because this material shows severely curved sin2Ψ diagram.
    In this study, a fundamental investigation was carried out to apply the X-ray residual stress measurement of the plating material. Fourth kinds of specimens with different thickness of film were prepared. X-ray elastic constants were obtained using the non-liner analysis. Influence of the film thickness on curvature of 2θ-sin2Ψ diagram was simulated. Residual stress in the plating layer was analyzed under the assumption that the stress state is equivalent biaxial.
    Some experimental results were observed: sin2Ψ diagrams were severely curved, and shape of diagrams shows varied by the film thickness and X-ray penetration depth. There is the steep stress gradient in the direction of depth.As the results, X-ray elastic constants of all specimens were independent from the thickness of film. Therefore, the value is constantly. A value of residual compressive stress calculated form present method is grater than value of sin2Ψ technique. Compressive stress decreased with the film thickness.
  • 廣瀬 明夫, 野尻 誠, 伊藤 大岳, 小林 紘二郎
    2000 年 49 巻 7 号 p. 767-773
    発行日: 2000/07/15
    公開日: 2009/06/03
    ジャーナル フリー
    A novel bonding process, which is a kind of diffusion bonding with cleaning the bonding surface followed by deposition of Ag-28mass% Cu alloy thin layer using ion beam sputtering, was applied to joining of commercial pure titanium (CPTi) under atmospheric pressure. The deposition of the Ag-Cu layer after removing the oxide film of the bonding surface successfully improve bondability of CPTi. The joint strengths depend on the thickness of the Ag-Cu deposited layer. A maximum joint strength close to the base metal strength is obtained using the optimum thickness of Ag-Cu deposited layer, 0.3μm, under the conditions of a bonding temperature of 1153K and bonding time of 300s or more. The thicker Ag-Cu deposited layer of 1.0μm in thickness results in a hardened microstructure including Ti2 (Cu, Ag) intermetallic precipitates and thereby lower strength and lower ductility after bonding at 1153K for 1800s. The joint with the thinner Ag-Cu deposited layer of 0.1μm in thickness is not bonded at all.
    The Ag-Cu deposited layers having 0.3μm or more in thickness become enriched in Ag during heating in the bonding process because of a greater diffusion coefficient of Cu than that of Ag in titanium. As a result a almost pure Ag layer is formed on the bonding surface after heating above 973K. The bonding is, therefore, considered to proceed via solid state diffusion bonding between the surface layers enriched in Ag and be completed after homogenization of the solute elements of Ag and Cu.
  • 堤 隆, 新井 広, 平島 健一
    2000 年 49 巻 7 号 p. 774-778
    発行日: 2000/07/15
    公開日: 2009/06/03
    ジャーナル フリー
    Very few studies on two dimensional elastic semi-infinite plane with circular hole subjected to arbitary loads at the circular hole are conducted for estimating displacement because of difficulties in treatment. This paper presents the method for estimating displacement of semi-infinite plane with circular hole subjected to arbitrary load on circular hole by using constraint-release technique which repeats superposing solutions of infinite plane with circular hole and semi-infinite plane to converge boundary conditions on both of boundaries. Some numerical results are shown by graphical representation.
  • 酒井 達雄, 武田 光弘, 塩澤 和章, 越智 保雄, 中島 正貴, 中村 孝, 小熊 規泰
    2000 年 49 巻 7 号 p. 779-785
    発行日: 2000/07/15
    公開日: 2009/06/03
    ジャーナル フリー
    In fatigue tests of high strength steels and surface hardened steels, a characteristic fatigue behavior such that S-N curve tends to come down again in the long life region of N>107 was often observed and reported by many researchers. When the mechanical design is based on the fatigue limit of the material, the above aspect introduces a typical difficulty to provide the reliability of the mechanical structures. In order to clarify such S-N characteristics in wide life region, a series of fatigue tests were performed by means of same type fatigue testing machines and same type of fatigue specimens in a definite high carbon chromium steel for the use of bearing as a collaborative study by the authors. Thus the complicated S-N property of this steel was tentatively interpreted as duplex S-N characteristics given by superposition of S-N curves for the respective fracture modes of the surface-originated fracture and the inclusion-originated fish-eye fracture.
  • 後藤 真宏, 山本 隆栄, 西谷 弘信, 酒井 達雄, 皮籠石 紀雄
    2000 年 49 巻 7 号 p. 786-792
    発行日: 2000/07/15
    公開日: 2009/06/03
    ジャーナル フリー
    In order to study the fatigue damage of a high carbon chromium bearing steel SUJ2, rotating bending fatigue tests of smooth specimens (Kt=1.06, stress concentration factor) were carried out. The specimens were finished by the grinding after the heat-treatment. The fatigue strength of EP-0 (ground) specimen exhibited large scatter and it tended to drop again in the long-life field in excess of 107cycles. In such a case, fish-eye was left on the fracture surface. In order to study the effect of surface hardened layer due to the grinding, two types of EP (electropolished) specimens, EP-15 specimen whose surface hardened layer and grinding flows were almost removed and EP-3 specimen which has the decreased surface roughness and surface hardened layer, were fatigued. The fatigue strength of EP-15 specimen was dramatically decreased when compared to the EP-0 specimen, and no drop in fatigue strength in the long-life field were observed. This indicates that the drop in fatigue strength in the long-life field results from the surface strengthened layer due to the grinding. On the other hand, S-N data of EP-3 specimen exhibit large scatter, but the range of scatter is smaller than that of EP-0 specimen. This narrowed scatter may be related to the decreased surface roughness of EP-3 specimen. Considering the experimental results of EP-15 and -3 specimens, the physical basis of peculiar S-N characteristics of EP-0 specimen was investigated.
  • 來海 博央, 田中 拓, 佐藤 敏弘, 田中 啓介
    2000 年 49 巻 7 号 p. 793-798
    発行日: 2000/07/15
    公開日: 2009/06/03
    ジャーナル フリー
    Fiber-reinforced plastics (FRP) were modeled by a two-dimensional laminated structure composed of an isotropic matrix and orthotropic fibers. The size of the plastic zone ahead of a delamination crack in the matrix under mode I and II loadings was estimated from the elastic stress distribution, and the estimated values were compared with the results computed by using an elastic-plastic finite element method. The height of the plastic zone was estimated from the contour of the Mises equivalent stress based on the elastic stress distribution without considering the stress redistribution due to yielding. The length of the plastic zone was estimated by considering the redistribution of matrix stresses due to yielding. The estimated sizes of the plastic zone height and length agree fairly well with the results computed by using the elastic-plastic finite element method. The limitation of the present estimation method was also clarified. For the case of small plastic zone under mode I and II loadings, the elastic stress distribution in the unreinforced matrix material under the same stress intensity factor can be used for the estimation of the plastic zone size. For the case of large plastic zone, the elastic stress distribution in homogeneous FRP model under the same load can be used only for the estimation of the plastic zone height under mode I loading.
  • 久保 善司, 服部 篤史, 栗原 慎介, 宮川 豊章
    2000 年 49 巻 7 号 p. 799-805
    発行日: 2000/07/15
    公開日: 2009/06/03
    ジャーナル フリー
    From the viewpoint of deterioration mechanism of concrete structures, water is one of the most important factor.Many kinds of surface treatments have been used to control water content of concrete. Surface treatments can be classified into two types based on water control of concrete. One type allows no movement of water into or out of concrete. The other type is hydrophobic treatment which restricts water penetration into concrete, but allows water vapour to move out. The former treatments may promote deterioration due to water remained in concrete. Thus, the silane treatments which are typical hydrophobic treatments have better performance as repair method. Recently, the use of solvent free silanes have been investigated because of safety of application and less influence on environment.In this study, hydrophobic performance of concrete treated with solvent free silanes was investigated. Furthermore, the influence of molecular structure and active ingredient content of silane on hydrophobic performance was investigated. The silanes of larger molecular weight had the better performance. Silane of molecular weight 262, which get larger impregnation content and hydrophobic layer, had the best hydrophobic performance. The influence of active ingredient content of silane of molecular weight 262 on the hydrophobic performance was not significant.
  • 藤川 雅史, 酒井 達雄, 青木 重正
    2000 年 49 巻 7 号 p. 806-811
    発行日: 2000/07/15
    公開日: 2009/06/03
    ジャーナル フリー
    Artificial aggregates made from the natural rocks are usually used as the concrete material, since the natural aggregates along the rivers can not be used due to the strict restriction to maintain the human society. The shape of these aggregates distinctly varies depending on the step of the producing processes such as blasting, crushing and screening. In this study, a quantitative analysis for the shape irregularity of such aggregates was attempted by applying the concept of fractal proposed by B.B. Mandelbrot. The Richardson effect was clearly confirmed between the total surface S and the measuring unit length ε. This fact indicates that the shape irregularity of the aggregates has the fractal aspect and the present method is applicable to the shape irregularity analysis. Thus it was finally found that the shape irregularity of the aggregates was successfully evaluated by combining the fractal dimension D and the body-shape irregularity index D*.
  • 三好 良夫, 田邉 裕貴, 高松 徹, 鮫島 貞一郎, 江嶋 毅, 上田 勝彦
    2000 年 49 巻 7 号 p. 812-818
    発行日: 2000/07/15
    公開日: 2009/06/03
    ジャーナル フリー
    In the sputter coating process, as a by-product, deposits are formed on the inner wall of the vacuum chamber, and a large number of particles are generating from the deposits. Today, the particle problem is recognized as one of the most serious because these particles create a high ratio of defective products. Recently, it has been observed that coating the inner wall of the vacuum chamber by metal spraying before sputter coating reduces the particle generation. But, a clear explanation of this mechanism has not been made. In order to clarify it, a fundamental study on the effect of pre-coating to a substrate by metal spraying on the properties of sputtered films was carried, out. The residual stresses in titanium-nitride films sputtered on the aluminum-alloy substrates coated with various sprayed films were measured by X-ray stress measurement. It was found that the residual stresses in sputtered titanium-nitride films manufactured on substrates coated by metal spraying were lower than those on substrates without pre-coating.In order to specify the determinant factors of residual stress in sputtered titanium-nitride film on the pre-coated substrate, the influence of the residual stress and the surface configuration of spray coating on residual stress in sputtered titanium-nitride film was investigated. It was found that one of the main factors affecting the residual stress was the surface configuration of spray coating, and with the residual stress increasing with an increase in the surface roughness of spray coating.
  • 大窪 和也, 藤井 透
    2000 年 49 巻 7 号 p. 819-824
    発行日: 2000/07/15
    公開日: 2009/06/03
    ジャーナル フリー
    An existence of flaws on glass fiber surface was directly confirmed. To characterize their size and distribution is also one of the objectives of this paper. An Atomic Force Microscope (AFM) was used in order to observe such sub-micron or nano flaws directly. From AFM observation, some sub-micron or relatively large flaws and cracks have been found. In order to estimate the size of those flaws and their distribution, static fatigue tests at high moisture and elevated temperature were conducted as well as static tensile test for single glass fibers at room temperature. The flaw size and their distribution were estimated. The strength distributions for single fibers taken from a roving and a plain weave fabric were also shown.
  • 木村 照夫, 濱田 泰以
    2000 年 49 巻 7 号 p. 825-828
    発行日: 2000/07/15
    公開日: 2009/06/03
    ジャーナル フリー
  • 井上 靖雄, 柏谷 賢治, 佐藤 幸雄
    2000 年 49 巻 7 号 p. 834
    発行日: 2000/07/15
    公開日: 2009/06/03
    ジャーナル フリー
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