材料
Online ISSN : 1880-7488
Print ISSN : 0514-5163
ISSN-L : 0514-5163
42 巻 , 478 号
選択された号の論文の19件中1~19を表示しています
  • 若宮 正行
    1993 年 42 巻 478 号 p. 771-779
    発行日: 1993/07/15
    公開日: 2009/06/03
    ジャーナル フリー
  • 管野 善則, 八島 正知, 垣花 真人, 吉村 昌弘
    1993 年 42 巻 478 号 p. 780-783
    発行日: 1993/07/15
    公開日: 2009/06/03
    ジャーナル フリー
    Wet corrosion by high temperature-high pressure water has been studied on CVD coated Ti base ceramic films (thickness ca. 10μm, TiC, TiN, TiC0.3N0.7, TiC0.3N0.7O0.1) at 300-680°C under 100MPa for 2h. The order of corrosion resistance was obtained as TiN>TiCN>TiCNO>TiC from the X-ray diffraction analysis of scale layers and the reaction ratio calculated from the weight gain. The order was discussed on the volume ratio φ defined by Pilling-Bedworth, the internal stress within the coated films, and the dissolution behavior of gaseous species at the interface of ceramic film-oxide scale. The oxide scale crystallized as anatase in TiC and transformed into rutile at higher temperatures. On the other hand, rutile deposited directly in other samples having a higher corrosion resistance.
  • 方 蘇春, 尾中 晋, 橋本 敏, 三浦 精
    1993 年 42 巻 478 号 p. 784-790
    発行日: 1993/07/15
    公開日: 2009/06/03
    ジャーナル フリー
    Copper bicrystals with Σ3{111} and Σ9{221} boundaries were deformed in tension and annealed for 900sec at temperatures between 773K and 1273K. Noticing grain and grain-boundary orientations of the specimens, the effects of grain boundaries on the recrystallization were discussed. In the case of the bicrystal where both of the primary slip planes in the grains were parallel to a grain boundary, the recrystallization behavior was almost the same with that of the single crystal of the component grain. On the other hand, in the bicrystals where the primary slip planes in grains were intersected at the grain boundaries, the grain boundaries in the bicrystals lowered the temperatures of appearance of new grains. The new grains were preferentially observed on the grain boundaries. In the case of the specimens where double slips took place in the grains from the early stage of deformation, no effect of grain boundaries on recrystallization was observed. The single crystal with double slips showed the lower temperature of appearance of new grains than those of the single crystals with single slips.Although the deformation behavior of bicrystals with Σ3{111} and Σ9{221} boundaries was almost the same at room temperature, the recrystallization of the bicrystal with the Σ9{221} boundary was easier. The difference in recrystallization behavior corresponded to the reported result that the grain-boundary diffusion coefficient of a Σ9{221} boundary was much larger than that of a Σ3{111} boundary.
  • 方 蘇春, 尾中 晋, 橋本 敏, 三浦 精
    1993 年 42 巻 478 号 p. 791-797
    発行日: 1993/07/15
    公開日: 2009/06/03
    ジャーナル フリー
    A plastically deformed copper bicrystal with a Σ9{221} grain boundary was annealed at 873K for 900sec and a copper polycrystal with an average grain size of 800μm was prepared. The orientation relationships of neighboring grains in the polycrystal after the recrystallization were measured by the back-reflection X-ray Laue method. The distributions of disorientation axes and angles of the grains were discussed using the coincidence-site lattice model. Many annealing twin boundaries with a Σ3 orientation relationship were observed in the polycrystal. Grain boundaries with Σ9 and Σ27 orientation relationships were observed in addition to the annealing twin boundaries, and the recrystallized structure was found to be dominated by the boundaries of Σ3n type. The orientations of Σ9 boundary planes were analyzed which formed Σ3+Σ3+Σ9 grain-boundary triple junctions with two Σ3{111} coherent twin boudaries. The stable orientations of the Σ9 boundaries corresponded to the planes where the plane density of coincidence-site lattice was high.
  • 上谷 保裕, 多々 静夫, 池野 進
    1993 年 42 巻 478 号 p. 798-803
    発行日: 1993/07/15
    公開日: 2009/06/03
    ジャーナル フリー
    Age-hardened Al-1 mass% Mg2Si-0.4mass%Si alloy specimens were deformed to 0.4% strain at room temperature. The accurate surface topographies of the grain boundaries and folds were observed by a scanning tunneling microscope.
    Large steps which accompanied a straight fold were clearly observed at the grain boundary. Frequently a diffuse and broad fold was also generated from the similar type of grain boundaries.
    Two types of folds as mentioned above were also generated from a different type of grain boundaries that might be slided parallel to the specimen surface. It was found by the detailed observation of the latter two types of folds that a deeply sinked surface exists always between a grain boundary and fold.
    In most cases, the direction of straight folds coincided with a slip trace in the grain. Formation of such straight folds can be estimated by using the stress transmission factor Nsf with a few exceptions.
  • 粕谷 平和, 美濃部 充好
    1993 年 42 巻 478 号 p. 804-810
    発行日: 1993/07/15
    公開日: 2009/06/03
    ジャーナル フリー
    In recent years the use of advanced composite materials as structural members has increased in various fields, because of their high specific strength and stiffness. One of the criteria for designing thin-walled structures is buckling stress under compressive loads. Usually, thin-walled laminated plates keep a stability condition after primary buckling. However, under continually increasing compression load, the equilibrium state of the plates changes to a state of higher buckling mode. The post-buckling behavior of thin laminated plates under axial compression has been discussed by many researchers. However, few studies have been performed on the secondary buckling phenomenon for thin laminated plates which occurs with a further increase in loading.
    In this paper, the stability condition of carbon fiber/epoxy (CFRP) cross-ply laminated plates with initial imperfections under uniaxial compression, which is simply supported along four edges, is determined using the second variation of the total potential energy. The occurrence of secondary buckling is proved analytically and the effects of various factors, such as initial imperfection, average axial shortening, post-buckling deflection pettern are discussed.
  • 永井 功, 田中 利光, 松川 真美
    1993 年 42 巻 478 号 p. 811-816
    発行日: 1993/07/15
    公開日: 2009/06/03
    ジャーナル フリー
    A damage process for perforation of a plain woven glass/epoxy composite laminate was studied, using an instrumented falling weight impact test. Changes in the damage were investigated at various levels of impact energy. The damage process was divided into three different stages, according to main crack growth with fiber breakage perpendicular to fiber directions. In the first stage, surface cracks grew. Then, through-thickness cracks propagated in the second stage. In the last stage, petal bending fracture occurred. After examining cracks by fluorescent penetrant method, the main crack area was calculated approximately. In the first and second stages, a linear relation between the crack area and the absorbed impact energy was obtained. Making use of the relation, quantitative characterization of the impact damage process can be achieved.
  • 川田 宏之, 島貫 洋, 小俣 英夫, 林 郁彦
    1993 年 42 巻 478 号 p. 817-822
    発行日: 1993/07/15
    公開日: 2009/06/03
    ジャーナル フリー
    In-plane Mode II fracture toughness tests on unidirectional GFRP are conducted using a fourpoint shear loading test method. In the previous paper, the four-point shear loading test method was examined as a simple Model II fracture toughness test. Then the effect of pre-crack length on fracture toughness was investigated. In this study, the same test method is applied to evaluate the Mode II fracture toughness. The dependence of the pre-crack length and the initial failure process are clarified. The results obtained are summarized as follows;
    (1) It is revealed that the crack opening displacement is much less than the crack relative sliding displacement in the four-point shear loading test.
    (2) From an analysis of the damage propagation length, it is found that the initiation of the main crack is close to the maximum load point. The initial failure behavior of the unidirectional GFRP subjected to shear loading is clarified.
    (3) The normalized stress intensity factor concerning an orthotropic body of the unidirectional GFRP is calculated by a finite element method. The mode II fracture toughness is constant irrespective of the pre-crack length.
  • 小川 俊夫, 岡崎 徳臣
    1993 年 42 巻 478 号 p. 823-828
    発行日: 1993/07/15
    公開日: 2009/06/03
    ジャーナル フリー
    The relation between compressive strength and density of honeycomb core was derived based on the theory of cylindrical shell buckling. The compressive strength should increase as a function of density of honeycomb core. The equation was applied to aluminum, aramid and polyimide honeycombs. Compressive strength increased as expected by the theory. For polyimide and aramid honeycombs, the experimental strength was coincident with that by the theory. However, for aluminum honeycomb, the strength in experiment was smaller than the calculated one. This result is caused by the localized failure at both ends of the honeycomb core.
  • 松岡 敬, 井原 辰彦, 高井 広行, 松富 達夫
    1993 年 42 巻 478 号 p. 829-835
    発行日: 1993/07/15
    公開日: 2009/06/03
    ジャーナル フリー
    An investigation was performed on the interface control of FRP using glass fiber treated by low temperature plasma. The treatment apparatus was developed in order to control plasma coating onto plain woven glass cloth. Three-point flexural tests of glass fiber reinforced epoxy composites were done by an Instron testing machine in order to examine the effect of the plasma treatment on the composite properties. The main results obtained were as follows:
    (1) NH3 gas plasma treatment was applied to improve the surface properties of the fiber: The contact angle between distilled water and surface of glass slide, substituted for the glass fiber to measure the contact angle, was decreased by this treatment. And the bending strength of FRP prepared with NH3 plasma treated fiber became higher than the one with the untreated fiber.
    (2) The bending strength of FRP varied as a function of plasma parameters such as the treatment power and the treatment pressure.
    (3) The improved adhesion state of the epoxy resin onto the glass fiber after NH3 gas plasma treatment was revealed by the SEM observation of the tensile fracture surface. It can be concluded from these results that the interfacial adhesion and the mechanical interlocking were increased by this process.
  • 水野 善久, 清水 敏之, 寺下 敬次郎, 宮南 啓
    1993 年 42 巻 478 号 p. 836-842
    発行日: 1993/07/15
    公開日: 2009/06/03
    ジャーナル フリー
    To design composite materials, and to optimize the manufacturing condition, quantitative evaluation of the dispersion state of filler contained in composite materials is important. In this study, the batch kneading of thermosetting resin and circular particles and the continuous kneading of thermoplastics resin and electric conductive fibers were performed, and the desperson state in these composite materials was evaluated with fractal dimension and coordination number. According to the evaluation, the fillers were dispersed in a uniform state if the value of fractal dimension was high, and the aggregation of the fillers was broken substantially if the coordination number had a lower value. Based on the relation between fractal dimension and the state of flow in the kneader as well as that between coordination number and the state of flow, the kneading mechanism was discussed. It became clear that the aggregation of the fillers was broken preferentially if elastic mixing was performed, and the diffusion of the fillers in the material was accelerated if counter-flow or diffusional mixing was pre-dominant. It was also pointed out that an excellent electric conductive resin could be obtained when the product of the fractal dimension and coordination number was a high value.
  • 鈴木 正治, 根本 康文
    1993 年 42 巻 478 号 p. 843-848
    発行日: 1993/07/15
    公開日: 2009/06/03
    ジャーナル フリー
    In order to improve durability of strength properties and dimensional stability perpendicular to wood grain, polyurethane resin-impregnated 3-ply plywood type composites were made of veneers in same thickness by using isocyanate of TDI-TMP adduct and ethylene glycol adipate. Ten to thirty percent amounts of propylene carbonate were added to polyurethane-forming systems in order to promote the penetration of resin into wood. The systems were formulated with an excess NCO-content for post-curing. Samples were impregnated with a solution formulated by the polyurethane-forming systems and pressed at 120°C for 30min after 24 hours cold pressing. For evaluating the combined effect of post cure and deterioration, the cured samples were soaked in cold water, boiling water, or a 10 percent aqueous solution of hydrochloric acid or caustic alkali. The impregnated quantities were varied substantially from 90 to 160 percent, including remaining diluent, depending upon aging or deteriorating treatments.
    Soaking in boiling water-and dry treatment, followed by volatilizing and leaching of diluent, increased the moduli of rupture and elasticity (MOR, MOE) perpendicular to or parallel to the surfacial fiber direction. The tensile strength of polyurethane resin film treated with soaking in boiling water showed a considerably higher value than the untreated one. The aging treatment gave much higher elasticity than the unimpregnated and untreated one.
    Acid or alkali treatments imparted much resistance to the resin impregnated samples. However, MOR and MOE of the samples subjected to weathering were less than those subjected to aging treatment.
    MOE perpendicular to the surfacial fiber direction was apparently related to diluent-excluding but clearly affected by the heat-stabilized and chemical reactivity of NCO-group. Some values of MOE of the samples subjected to weathering were surely higher than the untreated ones.
    The tensile-shear adhesive strength of the impregnated samples soaked in boiling water showed a considerably high value when propylene carbonate was added to resin. Other treatments also made an increase in adhesive strength.
    Swelling per unit moisture content change of the impregnated samples could be reduced significantly by each treatment except the caustic alkali treatment, accompanying reduction in equilibrium moisture content.
    Even if each treatment showed some aging and/or deteriorating effects, the combination of polyurethane resin in excess of isocyanate compound and crossed structure of veneers improved the mechanical properties perpendicular to grain, dimensional stability and bonding properties.
  • 青木 繁, 天谷 賢治, 幸 英昭
    1993 年 42 巻 478 号 p. 849-854
    発行日: 1993/07/15
    公開日: 2009/06/03
    ジャーナル フリー
    A new effective three-dimensional boundary element method is developed for predicting the galvanic corrosion rate of heat exchanger. Since a heat exchanger consists of a huge number of slender tubes and a brass tube plate direct application of conventional numerical procedures needs so many elements that computation becomes impossible.
    In the newly proposed method, the surface of the tube plate (which is connected to many tubes) is regarded as a surface of one virtual metal. At first, the polarization curve of the virtual metal is obtained by analyzing a tube unit which consists of one tube and a part of tube plate. Then the side water room is analyzed with a rather coarse mesh by employing the polarization curve of the virtual metal. Finally, the potential and current density thus calculated are used to determine the detailed distributions of potential and current density on the surfaces of an arbitrary tube and the tube plate.
    A real heat exchanger is analyzed by the proposed method to demonstrate its practical applicability. This method may be applicable not only to a corrosion problem of a heat exchanger, but also to heat conduction problems of similar structures.
  • 船見 国男, 清水 秀治, 江藤 元大
    1993 年 42 巻 478 号 p. 855-860
    発行日: 1993/07/15
    公開日: 2009/06/03
    ジャーナル フリー
    The purpose of this study is to establish a simple and rapid test method which can be used to investigate the possibility of occurrence of delayed fracture in high strength bolts. In this test, a specimen is immersed in hydrochloric acid (HCl) solution for some minutes under a tensile loaded condition with a load cell which is able to measure the clamping force, and then, the tensile test is perfomed after removing the specimen from the load cell.
    The main results are as follows:
    (1) It is necessary to finish the test within 30 minutes after acid dipping when the following test condition is used: the clamping force at 65% of tensile strength, 20% HCl solution temperature at 40°C and the dipped time for 40 minutes.
    (2) The possibility of occurrence of delayed fracture can be estimated by the ratio of tensile strength before and after acid dipping. As the result of this study, the strength ratio was lower than 0.8 for all the bolts in which the delayed fracture is said to occur.
    (3) In the range of tensile speed used (0.25-2.0mm), the tensile strength ratio was not affected by the tensile speed.
  • 後藤 穗積, 大森 舜二
    1993 年 42 巻 478 号 p. 861-867
    発行日: 1993/07/15
    公開日: 2009/06/03
    ジャーナル フリー
    Fretting wear experiments in air were carried out for a carbon steel, aluminum alloy, 60/40 brass, and stainless steels. The tangential force during the steady-state period of fretting and the average wear rate after a given number of fretting cycles were measured at various levels of contact load P and peak-to-peak amplitude S of relative displacement. As a result, the existence of a critical amplitude Scw of relative displacement was found for each material examined. Wear was very small below Scw and rapidly increased with S above Scw. The value of Scw/P strongly correlated with the strain of the materials corresponding to their fatigue strength.
    A change in wear mode with an increase in S is proposed as follows: in the region of elastic-adhesion contact at very small S wear debris is hardly produced because the contacting asperities are subjected to repeated stresses lower than the fatigue strength σw. In the mixed region of elastic-adhesion and microslip contact only the asperities in the microslip portion are subjected to repeated stresses higher than σw resulting in a small quantity of wear debris. Since in the macroslip region above Scw repeated stresses higher than σw act on the asperities over the whole contact area, much wear debris is generated by fatigue wear and shear fracture due to adhesion.
  • 長谷部 忠司, 坂根 政男, 大南 正瑛
    1993 年 42 巻 478 号 p. 868-873
    発行日: 1993/07/15
    公開日: 2009/06/03
    ジャーナル フリー
    This study investigates the effects of solidification direction on cyclic constitutive relation and creep-fatigue lives of Mar-M247LC Nickel-base directionally solidified (DS) superalloy. Strain controlled low cycle fatigue tests with 10 and 60min. hold-times in tension were carried out at 1173K in air for three kinds of specimens of which loading direction was 0°, 45° and 90° to the solidification direction. Step-up relaxation tests with a 10min. tension hold-time were also conducted for the three kinds of specimens to determine the material constants used in the creep constitutive equation. Creep-fatigue lives were significantly affected by loading direction when the fatigue lives were correlated with the total strain range; the 0° specimen had the maximum creep-fatigue life and the 45° specimen had the minimum life. On the other hand, the cyclic stress range gave a better correlation of creep-fatigue lives for all the specimens, which showed that stress is a better parameter for the life prediction. An elastic-plastic-creep constitutive equation was developed taking account of the anisotropy of Young's modulus, and the equation successfully predicted the experimental stress amplitude. The creep-fatigue life prediction method was developed based on the constitutive equation.
  • 伊藤 義康, 斉藤 正弘, 本多 啓三, 宮崎 松生
    1993 年 42 巻 478 号 p. 874-880
    発行日: 1993/07/15
    公開日: 2009/06/03
    ジャーナル フリー
    Low pressure plasma spraying is well suited for high-temperature protective coatings. In this coating process, coating adhesion is an important problem, and so surface roughness and cleaning achieved by the transferred arc method with negative substrate polarity have to be investigated in order to improve adhesion. In this paper, an experimental investigation was conducted to clarify the effect of the transferred arc treatment on the bonding strength of coatings. As a result, it was verified by SEM micrographs that the oxide scales could be removed by the transferred arc and the surface roughening effect was remarkable. It was also confirmed that grid blasting before the transferred arc treatment was effective for the uniformity of surface cleaning and roughening, and the thicker preoxidizing treatment was undesirable for the reason of insufficient surface cleaning. Namely, it was clear that the bonding strength of coatings was improved constantly by the grid blasting before the transferred arc treatment.
  • 出井 裕, 末澤 芳文
    1993 年 42 巻 478 号 p. 881-887
    発行日: 1993/07/15
    公開日: 2009/06/03
    ジャーナル フリー
    The purpose of this study is to develop palladium braze alloys for titanium alloy Ti-6Al-4V with jointing and cost characteristics superior to nickel-based or gold-based filler metals.
    This paper summarized the metallurgical and mechanical properties of titanium alloy Ti-6Al-4V joints with three types o f developed Pd-Cu system braze alloys, 30Pd-40Au-30Cu, 30Pd-60Cu-10Co, 30Pd-60Cu-10Ni, and the commercial nickle-based filler metal Ni-Cr-W-Fe-B-Si.
    The results obtained were as follows:
    (1) The intermetallic compounds Ti2Cu and TiCu were formed at the brazed joints with palladium braze alloys, and the intermetallic compound Ti2Ni was formed at the brazed joint with Ni-Cr-W-Fe-B-Si.
    (2) The joints brazed with the 30Pd-60Cu-10Ni filler metal had the highest tensile strength at room temperature at the joint clearance 0.10mm.
    (3) The 30Pd-60Cu-10Ni filler metal showed the highest tensile strength at 473K and 673K.
    (4) The most suitable palladium braze alloy tested for titanium alloy Ti-6Al-4V is the 30Pd-60Cu-10Ni braze alloy.
  • 西島 敏, 酒井 達雄, 戸梶 惠郎
    1993 年 42 巻 478 号 p. 888-894
    発行日: 1993/07/15
    公開日: 2009/06/03
    ジャーナル フリー
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