材料
Online ISSN : 1880-7488
Print ISSN : 0514-5163
ISSN-L : 0514-5163
34 巻 , 386 号
選択された号の論文の21件中1~21を表示しています
  • 坂井 徹, 大井 信一, 杉木 益規
    1985 年 34 巻 386 号 p. 1239-1244
    発行日: 1985/11/15
    公開日: 2009/06/03
    ジャーナル フリー
    The change in mechanochemical behavior of basic magnesium carbonate (4MgCO3·Mg(OH)2·4H2O) caused by vibrational grinding was investigated by means of the scanning electron microscopy (SEM), specific surface area measurement, X-ray diffractometry, infrared absorption spectroscopy, and thermoanalysis.
    It was found that the generation of fine particles and their granulation occurred in grinding from the observation in SEM. The specific surface area showed the maximum value at 20min, and decreased to a constant value after prolonged grinding.
    It was found from the powder X-ray diffraction patterns of the ground basic magnesium carbonate that the structural lattice irregularity and an amorphous phase were formed by grinding, and their amounts increased gradually with increasing grinding time.
    The effect of grinding on the pyrolysis of basic magnesium carbonate was also studied. From the X-ray diffraction patterns of the products made by pyrolyzing the original basic magnesium carbonate and the ground one at the heating rate of 2°C/min, it was found that the crystallized MgCO3 was produced in the dehydration reaction of the ground basic magnesium carbonate, while MgCO3 produced by the dehydration of the original basic magnesium carbonate was only the amorphous phase. It was also found from the result of thermoanalysis that the reaction rate of dehydration of the ground basic magnesium carbonate was higher than that of the original basic magnesium carbonate, whereas the reaction rate of decarbonation of the ground basic magnesium carbonate was lower than that of the original basic magnesium carbonate.
  • 荒川 正文
    1985 年 34 巻 386 号 p. 1245-1248
    発行日: 1985/11/15
    公開日: 2009/06/03
    ジャーナル フリー
    Much studies have been carried on the compaction of powder. However, fine powder has high cohesiveness and is considerably different in its behavior from usual powder of above several microns in particle size. In order to investigate the compaction process of high cohesive fine powder, the compacted samples were made from silicon nitride by the following methods:
    (1) uniaxial compaction of dried powder,
    (2) uniaxial compaction of dried granulated powder,
    (3) centrifugal compaction of slurry using ethanol as a medium,
    (4) uniaxial compaction of granulated powder wetted with ethanol, and
    (5) isotactic compaction of dried powder
    Each columner sample so obtained was cut into three equal parts in the longitudinal direction, and the apparent density, pore size distribution and compression strength of each specimen were measured. In the dried powder the compressive force was not transmitted enough through powder to the lower part because it was dissipated due to the internal friction of powder bed. Accordingly, the lower the position, the more are the porosity and heterogeneity of the body. In the wetted powder in which liquid filled up the pore volume of interparticles, the compressive force was transmitted enough through powder to the lower part because the granulated powder was deformed easily with compression, and therefore the powder can be formed into a uniform body having high strength. Although in isotactic compaction the applied force spread uniformly throughout, the mechanical strength of the resulting fabricated body was not so good. This suggests that some sliding planes are formed locally during compaction. The compaction process of each sample was discussed based on Cooper's equation representing the relationship between pressure and compressibility ratio.
  • 寺下 敬次郎, 古林 和夫, 小西 孝信, 宮南 啓
    1985 年 34 巻 386 号 p. 1249-1254
    発行日: 1985/11/15
    公開日: 2009/06/03
    ジャーナル フリー
    The tensile strength and other parameters of wet fine coal with various water contents were determined by tensile breakup and direct shearing tests, in which the period of aging after increasing the water content was also varied. On the basiss of the results obtained, the flowability of wet fine coal was evaluated.
    The tensile strength of wet fine coal in the pendular to funicular states increased with an increase of water content. However, in a mixture of funicular and capillary states the tensile strength either stayed almost constant or decreased after reaching a maximum value. The flowability of wet fine coal (wet powders) may be better evaluated by the tensile strength and shearing force rather than the internal friction factor. This implies that the higher the tensile strength and shearing force increase, the more the flowability is reduced. Furthermore, the prolongation of the aging period improves the flowability of wet fine coal, because the tensile strength is reduced by penetration of water into the coal particles.
  • 吉岡 哲也, 兼子 孝宏, 藤原 幸男, 吉村 慶英
    1985 年 34 巻 386 号 p. 1255-1259
    発行日: 1985/11/15
    公開日: 2009/06/03
    ジャーナル フリー
    In this report, the mixing mechanism of a binary system of particles with different electric resistance, group A and group B, was treated by the use of a two-dimensional model. Before mixing, the particles of group A and group B were arranged in a parallel circuit, as shown in Fig. 1, (c).
    Accompanied with the beginning of rotation of impellar blades at an angular velocity ω1-3, the particles belonging to 1, 2, 3 orbits began to move in their orbits at the same velocity as that of impellar blades, while the particles belonging to 4, 5 orbits had less velocities (ω4, ω5) than ω1-3.
    Together with the rotational motion of particles, the random exchange of positions of particles occurred. Thus, the resulting equation was as follows.
    R=l×e-kt×|∑ai×sin(ωi×t)|+(m-n×e-kt)
    where,
    R: Total electric resistance
    ai, k, l, m, n: Constant
    ωi: Angular velocity
    t: Time
  • 山崎 利春
    1985 年 34 巻 386 号 p. 1261-1266
    発行日: 1985/11/15
    公開日: 2009/06/03
    ジャーナル フリー
    A numerical method of analyzing fracture mechanics parameters for interface crack was presented. This method utilizes the node-point displacement and node-point load of finite element analysis to evaluate the stress intensity factor K.
    As an example, the K value of cracks in a homogeneous material was evaluated with the mesh size having 5-10% of the crack length and high accuracy with less than 5% error was obtained.
    For cracks on the Al/epoxy bi-material interface, the Mode-I stress intensity factor evaluated with or without no-slip zone was found to be analogous to the analysis by Mak et al. Also a linear relationship was found between KI and the stress σyy in the crack tip element irrespective of material combination, stress state or loading condition.
  • 田中 学, 富田 信, 飯塚 博, 葦原 文夫
    1985 年 34 巻 386 号 p. 1267-1270
    発行日: 1985/11/15
    公開日: 2009/06/03
    ジャーナル フリー
    The effects of microstructure on internal friction (strain amplitude for measurement≈1×10-4) and Young's modulus have been investigated for the heat-treated specimens of commercial 80kgf/mm2 grade high-tensile strength steel (HT 80).
    It was found that the internal friction was strongly affected by the distribution of carbide particles in the interior of the grain. The internal friction abruptly decreased with a decrease of particle spacing below about 1×10-6m. This can be correlated with a decrease of magneto-mechanical histeresis loss. Young's modulus increased with an increase in the amount of carbides in the steel which resulted in a decrease in dissolved carbon content in the matrix.
    It was revealed that the as-received steel (sorbite structure) had the largest Young's modulus and the smallest internal friction, while the annealed specimen (coarse sorbite) showed an excellent combination of large internal friction and large Young's modulus. The surface finishing also influenced the internal friction of specimens.
  • 深浦 健三, 泉 久司, 川辺 秀昭
    1985 年 34 巻 386 号 p. 1271-1276
    発行日: 1985/11/15
    公開日: 2009/06/03
    ジャーナル フリー
    X-ray and TEM investigations were performed to clarify plastic deformation in cold streching of micro-duplex stainless steel. The X-ray line broading was obtained by the Garrod and Auld method which utilizes a single reflection only. The main results obtained were summarized as foolows; Most of the deformation occurred in the soft austenite phase and the two phases tended to deform more or less at the equal stress. In the case of aging at 748K, the hardness of ferrite phase increased, owing to the precipitate of Cr-rich phase and the two phases tended to deform with the equal strain. The reason was due to the decrease in continuity of softer austenite phase. By aging, twinning occurred in coarse grained steel. But it was restricted remarkably when the grains of both phases were fine. The main reason of this was due to the fine dispersion of the soft austenite phase. When the domain size by the X-ray method and the magnitude of inter-slip region (cell size) by the transmission electron microscopy method were compared, the former was larger than the latter by a factor of 2.
  • 飯田 誠, 高橋 太喜彦, 後藤 昌生, 宮野 靖
    1985 年 34 巻 386 号 p. 1277-1282
    発行日: 1985/11/15
    公開日: 2009/06/03
    ジャーナル フリー
    Rigid polyurethane RIM (Reaction Injection Molding) produces an integral-skin foam consisting of a high density skin layer and a low density core layer. In the three-point bending tests of such moldings made by RIM, their failure modes were classified as follows;
    (1) The skin layer on the tensile side at the loading point was failed by tensile stress.
    (2) The skin layer on the compressive side at the loading point was failed by compressive stress, causing wrinkling buckling. In the previous paper, basic equations were derived to predict the flexural properties of the moldings made by RIM, which showed the above two failure modes. The experimental results were successfully explained by using these equations. In this paper, the optimum layer structure was discussed in two cases. One was concerned with the layer structure that maximizes the flexural strength of the moldings made by RIM with a given overall density, and the other was concerned with the layer structure that minimizes the overall density of the moldings made by RIM with a given flexural strength. In addition, the effect of material constants expressing mechanical properties of rigid polyurethane and polyurethane foam on flexural strength was discussed.
    The results obtained here should be useful to the optimum structural design of the moldings made by RIM.
  • 一次元平板の場合
    古川 俊雄, 竹内 洋一郎, 若杉 昇八
    1985 年 34 巻 386 号 p. 1283-1288
    発行日: 1985/11/15
    公開日: 2009/06/03
    ジャーナル フリー
    The present paper deals with the influence of thermomechanical coupling on the maximum thermal stress in a one-dimensional plate in detail. Investigations were done by varying the factors related to the maximum thermal stress ratio. The factors examined were the coupling parameter, Biot's number and Poisson's ratio. Though close form solutions were obtained for a plate heated on its both surfaces, the numerical analysis was performed for a plate heated on one surface.
    The results obtained are summarized as follows:
    (1) The rate of increase of the maximum thermal stress ratio for the coupling parameter tends to decrease gradually.
    (2) The maximum thermal stress ratio is largest when Biot's number at the unheated surface side is 0 and that at the heated surface side is nearly 4.
    (3) The maximum thermal stress ratio increases almost linearly with the decrease of Poisson's ratio.
    The above maximum thermal stress ratio is the quantity defined by |(σδmax0max)/σ0max|×100 (%), where σδmax and σ0max are coupled and uncoupled maximum thermal stress, respectively.
  • 丸山 公一, 原田 千里, 及川 洪
    1985 年 34 巻 386 号 p. 1289-1295
    発行日: 1985/11/15
    公開日: 2009/06/03
    ジャーナル フリー
    A strain ε vs. time t equation taking account of tertiary as well as primary and secondary creep stages, that is, ε=ε0+A(1-e-αt)+B(eαt-1) was proposed and applied to the creep data of a 1Cr-1Mo-1/4V steel. Here, ε0, A, B and α are constants which vary with stress and temperature. This equation described sufficiently well the creep curves up to the tertiary stage.
    The constants in the equation were determined by the least square regression method and their stress and temperature dependences were examined. The constants relating to strain, ε0, A and B, were invariable with temperature, suggesting that their values obtained experimentally can be adopted directly in long-term creep curve prediction at lower temperatures under the same stress. The time constant α was found to be given as a simple function of minimum creep rate whose stress and temperature dependences have been well established, so that the α value can be extrapolated to longer time with high accuracy.
    The equation proposed in this study was able to represent creep curves up to the tertiary stage, and furthermore the stress and temperature dependences of the constants in it were very favorable for long-term creep curve prediction. Thus, the equation is considered to be more useful than any other equation proposed so far for this purpose.
  • 今中 誠, 岸本 和一郎, 沖田 耕三, 中山 英明, 白戸 紋平
    1985 年 34 巻 386 号 p. 1296-1300
    発行日: 1985/11/15
    公開日: 2009/06/03
    ジャーナル フリー
    Adhesive bonded lap joint is fundamental to many adhesive joint design in industry. Hence, to investigate the effects of basic factors, such as over-lap length, on its fatigue strength is important to establish the design standard for the lap joint.
    In this study, the effect of over-lap length on fatigue strength was investigated using a single lap joint bonded with an epoxy-polyamide adhesive under impact and non-impact stress conditions.
    From the comparison of the non-impact fatigue strength τmax and the static shear strength τb by taking the over-lap length as a parameter, it was revealed that the longer was the over-lap length, the lower was the non-impact fatigue strength, τmax, and also the value of τb became lower at the same degree as that of τmax, as given by the following correlation. τmaxb=1.71Nf-0.12 where Nf is the number of stress cycles to failure.
    However, when the impact fatigue strength on the S-N diagram was compared with the non-impact one, it was observed that the former showed more rapid lowering trend with increasing number of stress cycles than the latter. Furthermore, with increasing the over-lap length, or with increasing the stress concentration factor, the impact fatigue strength decreased more rapidly than the non-impact fatigue strength.
  • 田中 啓介, 秋庭 義明
    1985 年 34 巻 386 号 p. 1301-1307
    発行日: 1985/11/15
    公開日: 2009/06/03
    ジャーナル フリー
    The interaction of a crack-tip slip band with the grain boundary has been modeled for three cases: the slip band which does not reach the grain boundary, the slip band blocked by the grain boundary, and the slip band propagating to the adjacent grain. The continuously distributed dislocation theory was used to compute the crack-tip opening displacement (CTOD) and the microscopic stress intensity factor. The propagation rate of a short crack growing under the interaction with the grain boundary was discussed under the assumption that the range of CTOD directly determines the crack growth rate. The propagation behavior of a short crack was predicted as a function of the distance between the crack tip and the grain boundary, and of the difficulty of slip propagation to the adjacent grains, as well as of the crack length and stress level.
  • 幡中 憲治, 松岡 秀理, 山田 敏郎
    1985 年 34 巻 386 号 p. 1308-1314
    発行日: 1985/11/15
    公開日: 2009/06/03
    ジャーナル フリー
    The annealed copper and JIS S15C steel were fatigue-tested under rotating bending and the growth behavior of microcracks was examined through an optical microscope. The distribution of crack size was found to be described by either a single straight line or a broken line on the Weibull plot. The appearance of the break is due to the coalescence of pretty large cracks of the size from about 100 to 200μm. The maximum crack size plotted against the ratio of a given cycle number to that to failure, N/Nf, increased discontinuously around N/Nf≅0.4 in copper. On the other hand, it rose continuously in the most part of fatigue process in S15C steel and a sudden ascent on this curve occurred around N/Nf≅0.6-0.8. Such a discontinuous increase in the maximum crack size is also due to the coalescence of pretty large cracks mentioned above. These results indicate that the fatigue process is controlled mainly by the gradual growth and connection of microcracks less than about 100-200μm in size in S15C steel, while the discontinuous joining of pretty large cracks dominates the fatigue process in copper.
    The relation between the maximum crack size and the cycle ratio, N/Nf, was almost independent of cyclic stress level in copper, while it was definitely influenced by this in S15C steel. The magnitude of cumulative cycle ratio in the double repeated fatigue tests under two step stress amplitudes, which had been found to be dependent on the kind of materials, was reasonably interpreted through such crack growth behaviors.
    The Frenche's damage lines were found to be located at N/Nf≅0.1 and 0.50 in copper and S15C steel, respectively. The cracks of about 120μm in size were formed at these lines in both materials.
  • 中島 正貴, 加藤 容三, 中村 和司
    1985 年 34 巻 386 号 p. 1315-1320
    発行日: 1985/11/15
    公開日: 2009/06/03
    ジャーナル フリー
    The effect of mean load on the fatigue crack growth behavior of a high strength steel has been investigated. The material used was SNCM 439 tempered at 200°C. The specimens were loaded in in-plane bending at a cyclic frequency of 2000 cycles per minute at various stress ratios (R) and mean stress intensity factors (Kmean) under hydrogen supply. The results of fatigue crack growth at various stress intensity ranges (ΔK) were arranged in terms of Kmean and maximum stress intensity (Kmax) in order to characterize the effect of mean load. At all ΔK levels, the acceleration of crack growth rate occurred beyond the level of Kmean=KISCC. In the region of Kmean<KISCC, the fatigue crack growth behavior depended on ΔK level, irrespective of Kmean level. On the other hand, in the region of Kmean>KISCC, crack growth was dominated by Kmax level. These results were also confirmed by fractographic observations.
  • 御牧 拓郎, 橋本 敏, 三浦 精
    1985 年 34 巻 386 号 p. 1321-1326
    発行日: 1985/11/15
    公開日: 2009/06/03
    ジャーナル フリー
    In order to clarify the SCC behavior of Cu-9 at%Al alloy single crystals, SCC tests were carried out in (NH4OH+NaOH) solution at 303±2K. At stress levels lower than the yield stress SCC was never initiated, and slip steps induced by prestraining did not influence the SCC behavior. On the other hand, SCC was observed in all specimens tested and fractured under a stress higher than the yield stress. SCC was mainly initiated along the primary slip trace and propagated macroscopically along {110} trace. However, observations at higher magnifications showed that cracks were propagated alternately along {111} and {110} traces.
  • 御牧 拓郎, 福永 浩, 橋本 敏, 三浦 精
    1985 年 34 巻 386 号 p. 1327-1332
    発行日: 1985/11/15
    公開日: 2009/06/03
    ジャーナル フリー
    The effect of grain boundary on stress corrosion cracking (SCC) was studied on Cu-9 at%Al alloy bicrystal specimens with <111>-tilt Σ=13b coincidence boundary in (NH4OH+NaOH) solution at 303±2K. It was found that SCC occurred in all specimens having the stress ratio (σay) between 0.92 and 1.25, where σa and σy are the applied and yield stresses, respectively. Susceptibility to SCC was found to be much greater at the grain boundary compared to the crystal surface, and all specimens fractured intergranually. Time for the initiation of SCC at grain boundary was found to depend on the applied stress ratio. Prestraining made the alloy more susceptible to SCC at grain boundary and accelerated the crack initiation at grain boundary. No influence of prestraining on SCC at crystal surface was observed.
  • 八木 晃一, 久保 清, 金丸 修, 田中 千秋
    1985 年 34 巻 386 号 p. 1333-1339
    発行日: 1985/11/15
    公開日: 2009/06/03
    ジャーナル フリー
    The combined creep-fatigue loading tests were carried out on SUS 304 stainless steel. The data obtained were evaluated using the linear life fraction damage rule. The results evaluated were discussed in connection with the creep fracture modes. The specimen under combined creep-fatigue loading was ruptured by an accumulation of either creep damage (φc) or fatigue damage (φf), when the creep loading condition of combined creep-fatigue loading test lay in the transgranular fracture region on the creep fracture mode map obtained from the static creep rupture test. When the creep loading condition lay in the region of intergranular fracture due to growth of cavities, the rupture life under combined creep-fatigue loading was affected by both φc and φf, and the relation of φc and φf was φcf≈1. The connection between the φc vs. φf relation and creep fracture modes obtained for SUS 304 stainless steel was the same as that obtained for SUS 316 stainless steel.
    The φc vs. φf relation obtained for the present steel was compared with the φc vs. φf relation obtained from the interspersion test in MPC. It seems that the creep loading condition of the interspersion test lies in the region of intergranular fracture due to the growth of wedge-type intergranular cracks on the creep fracture mode map.
  • 大谷 隆一, 木南 俊哉
    1985 年 34 巻 386 号 p. 1340-1345
    発行日: 1985/11/15
    公開日: 2009/06/03
    ジャーナル フリー
    The propagation rate of distributed creep microcracks is influenced by the microstructure and the inhomogeneous local deformation, and it may not follow a definite law but depend on a probabilistic characteristic, i.e., the time and space scattering of crack initiation and the fluctuation of crack propagation rate. The crack density, n(t), and the distribution of crack length, f(c), which are closely related to the initiation and propagation of distributed creep microcracks, can be measured rather easily at any time. In this paper, a method for the estimation of the microcrack propagation, rate using n(t) and f(c) was proposed based on the supposition that no definite distribution of crack propagation rate exists. The crack propagation rate was estimated on 304 stainless steel in which surface microcracks of the size of more than one grain boundary facet were observed during creep in air and in vacuum at 650°C. The estimated propagation rate was close to the maximum crack propagation rate measured as far as the applied stress dependence was concerned. It is supposed that a better estimation is obtainable if the length of creep microcracks is measured more accurately at the early stage of the propagation.
  • W, Cr, Fe, SUS 304およびInconel 600
    三浦 嘉也, 高橋 克明, 瀬政 利樹
    1985 年 34 巻 386 号 p. 1346-1351
    発行日: 1985/11/15
    公開日: 2009/06/03
    ジャーナル フリー
    In the previous paper, the electrochemical phenomena of Ni and Mo in a molten silicate glass of the composition 16 Na2O·12 CaO·72 SiO2 in wt% were investigated. In this paper, W, Cr, Fe, SUS 304 and Inconel 600 were chosen as the objects to be measured. Anodic dissolution, passivation and cathodic deposition for these metals were investigated by linear potential sweep voltammetry at various potential sweep rates (5-0.05V/sec) with platinum reference and auxiliary electrodes in Ar gas atmosphere or in air. Moreover, the metal-glass interface after polarization was analysed by EPMA.
    On cathodic potential sweep of every metal investigated here, silicate anions were easily reduced to silicon element and a kind of silicide layer covered the electrode surface. Since the silicide has high electrical resistance, its formation made the measurement of voltammogram difficult at slower sweep rates.
    The anodic voltammogram of W at 3V/sec showed a large current peak around 1.7V (relative to Pt reference). The peak potential shifted to more cathodic direction with decreasing sweep rate. The current peak was attributed to the formation of a passsive layer on the W electrode. The occurrence of tungsten oxide layer with 30μm thick on the W electrode was confirmed by EPMA. The oxide layer seemed to be made up by WO3. The broad current peak was observed on anodic voltammogram of Cr due to the formation of chromium oxide Cr2O3. There was no peak on the anodic current-potential curve for the Fe electrode and Fe dissolved rapidly and easily. Both SUS 304 and Inconel 600 were subject to passivation by oxide film formation of Cr2O3 and NiO on anodic polarization.
  • 黒部 利次, 今中 治, 石橋 信彦
    1985 年 34 巻 386 号 p. 1352-1355
    発行日: 1985/11/15
    公開日: 2009/06/03
    ジャーナル フリー
    A Plasma-assisted fine particle classification method has been developed by using a positive column of glow-discharge in the Geisler tube. The particles are charged in plasma, in which their surface is covered with the sheath made of double layers of negative and positive ions. Charged particles fly to the positive electrode under high tension voltage. The flying mode, however, is influenced by the gravity and the collision of the plasma ions to the flying particles. A newlydeveloped classification setup is made with three main parts -the Geisler tube, a powder supplier and an evacuation system. The fine powders such as those of alumina, sillica and silicon carbide, were classified under the condition of DC voltage of 2kV and the tube current of 1.5mA at 1Torr. It was found from the experiments that the coaser particles fell down near the inlet of the powder supplier, but the finer ones flew apart from it. The classification characteristics may be determined by the charging mode and the electric property of particles.
  • 4. 衝撃破壊と破壊じん性
    坂田 勝, 岸本 喜久雄
    1985 年 34 巻 386 号 p. 1356-1362
    発行日: 1985/11/15
    公開日: 2009/06/03
    ジャーナル フリー
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