著者

攝津 暢浩 高橋 学 松下 正史 岡部 永年

出版者

The Society of Materials Science, Japan

雑誌

材料 (ISSN:05145163)

巻号頁・発行日

vol.61, no.6, pp.530-536, 2012

被引用文献数

6

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We investigate the mechanical strength of ceramic/metal composites subjected to cyclic thermal loading. First, test samples of Cu/AlN systems are prepared via brazing. Next, short-term thermal cycle tests (25, 50, and 100cycles) are conducted at temperatures ranging from -40 to 125°C. Four-point bending tests are conducted to evaluate the residual strength. Further, thermal stress analysis is performed using the finite element method in order to examine the thermal stress behaviors during cyclic heating. The results reveal that the residual strength increases during 0∼20cycles because of residual thermal stress relaxation. This relaxation is generated by the cyclic softening of the metals owing to combined hardening. In contrast, relatively long-term thermal cycling (20∼100cycles) reduces the residual strength owing to damage growth to AlN. The AlN plates exhibit variability in residual strength, and the distribution of the residual strength for each cycle number conforms to the two-parameter Weibull curve. The variability in residual strength increases with the cycle number, and it is attributed to variabilities in the pre-existing crack size and damage accumulation. We conclude that the residual strength of the Cu/AlN composites depends on the thermal stress behavior and damage growth to the AlN plates.

著者

若杉 三紀夫 山本 高広

出版者

社団法人日本材料学会

雑誌

材料 (ISSN:05145163)

巻号頁・発行日

vol.40, no.457, pp.1372-1378, 1991-10-15

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The effects of three types of polymer modification on both hydration characteristics and physical properties of the gypsum pastes and mortars originated from anhydrite plaster have been studied at various polymer-gypsum ratios. The polymer dispersions used were ethylene-vinyl acetate (EVA), polyacrylic ester and styrene-butadiene rubber. The degree of hydration of the gypsum pastes and mortars was examined by X-ray diffraction, scanning electron microscopy, differential scanning calorimetry and porosity measurement. The setting time of fresh gypsum mortars (polymer-modified and unmodified) as well as the physical properties of hardened gypsum mortars were also measured. The hydration was complete in about 3 days, and the degree of hydration of the polymer-modified gypsum mortars was smaller than that of unmodified mortar. The setting time of gypsum mortars was retarded by the addition of polymer, and was affected by the chemical structure of polymer. The flexural and tensile strengths of the EVA-modified mortar with a polymer-gypsum ratio of 5% were higher than those of unmodified mortar. Its elastic modulus was the smallest of all, and further EVA-modified mortars showed small linear expansion. From the above test results, the EVA-modified gypsum mortar with a polymer-gypsum ratio of 5% was shown to be one of the candidates of the better plastering materials for polystyrene and polyurethane foams.

著者

大内田 久 西岡 章夫 岩崎 勤

出版者

公益社団法人 日本材料学会

雑誌

材料 (ISSN:05145163)

巻号頁・発行日

vol.12, no.117, pp.451-456, 1963-06-15 (Released:2009-06-03)

参考文献数

6

被引用文献数

1

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The present investigation has been made in order to determine the influence of induction-hardening on the fatigue strength of shrink-fitted specimens. Cyclic direct stress fatigue tests were made on shrink-fitted specimens 20mm in diameter of NiCrMo steel.The results obtained were summarized as follows:1. The reduction ratio 2.3 was obtained by comparing the endurance limit for a shrink-fitted specimen with that of a plain specimen.2. The endurance limit of a shrink-fitted specimen was increased by about 2.1 times by induction-hardening.3. The fatigue strength of the induction-hardened specimen with a shink-fitted member may be estimated approximately from the modified Goodman diagram, in which the residual compressive stress on the surface layer of specimen is assumed to be mean stress.

著者

大路 清嗣

出版者

社団法人日本材料学会

雑誌

材料 (ISSN:05145163)

巻号頁・発行日

vol.32, no.359, pp.935-941, 1983-08-15

被引用文献数

1

著者

岡村 弘之

出版者

社団法人日本材料学会

雑誌

材料 (ISSN:05145163)

巻号頁・発行日

vol.32, no.360, pp.1062-1067, 1983-09-15

著者

江原 隆一郎

出版者

社団法人日本材料学会

雑誌

材料 (ISSN:05145163)

巻号頁・発行日

vol.47, no.8, pp.874-880, 1998-08-15

参考文献数

35

著者

岸本 昭

出版者

社団法人日本材料学会

雑誌

材料 (ISSN:05145163)

巻号頁・発行日

vol.14, no.139, pp.264-269, 1965-04-15

被引用文献数

1

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Kamaboko is a heat-coagulated fish paste containing some salt, sugar, starch and flavor, and is one of the favorites of Japanese people. The rupture properties of Kamaboko, such as the breaking strength and the breaking elongation, are considered as one of the most important factors in evaluating the commercial quality of this product. The quality of Kamaboko has been estimated in terms of pastelike compactness which in Japanese is known as "Ashi". This in reality embodies rheological properties. The results of ranking Kamaboko on market by "Ashi" or compactness have shown that this is closely ralated to its being hard, but not so much so as to be tough, and also to its being fit for chewing chear cut. The organoleptic scores for the Kamaboko, how hard it is, were found to be related to the gel strength, the elastic energy stored in the specimen before breaking. On the contrary, the evaluation of Kamaboko being fit for chewing clear cut has not yet been breaking. On the contrary, the evaluation of Kamaboko being fit for chewing clear cut has not yet been established. The data for the creep in a simple shear, the stress relaxation in extension and the damped free oscillation in torsion of commercial Kamaboko have shown that this is considered to be a thermorheologically simple material and a slightly crosslinked rubbery material which exhibits no viscous flow. The results of stress relaxation of fresh fish meat paste were expressed as : [numerical formula] where &fnaf; is the stress at time t,&fnaf;_10 the value of &fnaf; at t=10sec, a and k the constants, and t the time, respectively. The stress relaxation measurements were made for the meat paste heated at various temperatures and heating time. It was found that the values of &fnaf;_10 increase and those of k decrease with increase of temperature and heating time. The measurements of the viscosity of the fish muscle extracts were made at various velocity gradients. The relation between the viscosity, η, and the velocity gradient, D, followed the de Waele-Ostwald law: η=K D^n where K and n are constants. Moreover, the viscosity,η, of fish muscle extracts at constant velocity gradient was found to be related to the concentration C as : η_<D=2> = kC^m.

著者

木村 和成 犬飼 隆夫 斎藤 潔 柏谷 英夫

出版者

社団法人日本材料学会

雑誌

材料 (ISSN:05145163)

巻号頁・発行日

vol.38, no.425, pp.175-181, 1989-02-15

被引用文献数

1

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Older thermal power plants are increasing in number today which are to be used beyond their design lives. In order to keep their high performance and to extend their useful lives, it is quite necessary to fully understand the degradation phenomena of the component materials during service operation and to make more accurate life assessment. The embrittlement , one of the typical material degradations, was investigated for the CrMoV steam turbine rotors retired after long time service at high temperatures in thermal power plants, as well as for the laboratory aged rotors. The V notch Charpy impact tests showed a remarkable increase in the fracture appearance transition temperature (FATT) in some rotors. The Auger electron spectroscopy analysis indicated that this increase was attributable to the phosphorus segregation to the grain boundary. The electrochemical polarization (ECP) test was applied to the rotor samples and the value of ECP minimum current density, which was corrected for the grain size obtained by the metallographical investigation of replica taken from the ECP test surface, was found to be a very good measure of the embrittlement. Based on these informations from ECP test, replica observation and rotor production record, a nondestructive method for evaluating in-service toughness degradation of CrMoV steam turbine rotors was presented. According to this method, the degraded FATT of a CrMoV rotor could be estimated within ±20℃.

著者

宮入 裕夫 北條 正樹

出版者

社団法人日本材料学会

雑誌

材料 (ISSN:05145163)

巻号頁・発行日

vol.45, no.10, pp.1071-1077, 1996-10-15

被引用文献数

3 1

著者

横井 秀輔 榎本 三郎

出版者

社団法人日本材料学会

雑誌

材料 (ISSN:05145163)

巻号頁・発行日

vol.21, no.225, pp.589-593, 1972-06-15

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In order to investigate the mechanism of binding silicate as additive, the tablets were measured with respect to its hardness, which had been compressed with several kinds of magnesium aluminosilicate, and the process of its compression was observed. As the result of this experiment it has been ascertained that the hardness of the tablet is related to the specific surface area and to the apparent specific volume of magnesium aluminosilicate, and that the tablet itself becomes higher in hardness as the additive becomes lower in particles size. In the process of compression the secondary aggregate particles are considered to be distracted and to get dispersed into the base. The scanned electron micrographs will substantially represent the mechanical action of the secondary aggregate particles. The magnesium aluminosilicate is considered to act as binder by its porous fine particles in fiber forms increasing the number of contact points, and making interprticle crosslinkage among the base particles, and forming the interparticle bridge after the occurrence of plastic deformation, and further making mechanical nets of finely divided magnesium alminosilicate itself.

著者

熊谷 直一 笹嶋 貞雄 伊藤 英文

出版者

社団法人日本材料学会

雑誌

材料 (ISSN:05145163)

巻号頁・発行日

vol.27, no.293, pp.155-161, 1978

被引用文献数

11

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Kumagai and Itô, since August 7, 1957, have been carrying out the measurements of creep, by bending, of two large beams of granite of a size of 215×12.3×6.8cm. The results obtained in 7, 10 and 13 years were published in this journal: Vol. 14 (p. 507), Vol. 17 (p. 925) and Vol. 20 (p. 185), respectively. Those obtained hitherto in nearly 20 years are given in this paper, which shows that the creep rate today is almost the same as that 10 years ago. And we have come to the conclusion that granite can do a plastic flow with a vanishingly small yield stress, <i>i.e</i>. a viscous flow. The viscosity of granite under the normal temperature and pressure is 3∼6×10²⁰ poises as found from the general trend of the creep.<br>Itô and Sasajima, since August, 1974, have been carrying out the similar measurements on three granite and three gabbro beams of smaller sizes, 21×2.5×2.0cm and 16×2.0×1.5cm, respectively. In these experiments, an optical flat was set on the upper polished surface of the beam bent convex upward to produce interference fringes of Na-D monochromatic light. By analysing the fringes, the profile of the upper surface was determined to an accuracy of one-tenth of one wavelength. The routine determination of the profile gave a change in the amount of bending with time. Although only 2.5 years have passed, it has been found that the secondary creep of the granite specimens in the general trend is comparable with that found in the previous experiment. As for the gabbro specimens, such a creep has not yet been observed clearly.<br>During the above two experiments, it has been observed that the creep does not show a steady and monotone progress, but does a repeated"return-back"with an irregular interval of more or less than one year. This strange phenomenon was first noticed after correcting the results of the former experiment for the annual variation of humidity. The latter experiment, being carried out in a constant humidity of neary 100%, shows a similar phenomenon.

著者

村上 敬宜 横山 ナンシー尚子 高井 健一

出版者

社団法人日本材料学会

雑誌

材料 (ISSN:05145163)

巻号頁・発行日

vol.50, no.10, pp.1068-1073, 2001-10-15

被引用文献数

10 23

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The mechanism for fatigue failure in extremely high cycle fatigue in the regime of <i>N</i>>10⁷ is studied on a bearing steel, JIS SUJ2. Special focus was given to the fracture morphology in the vicinity of fracture origin (subsurface nonmetallic inclusion) of a heat treated bearing steel (Specimen QT). The particular morphology looks dark during optical microscopic observation. Specimens with short fatigue life of the order of <i>N_f</i>=10⁵ did not have such a dark area, ODA (optically dark area). To investigate the influence of the hydrogen trapped by nonmetallic inclusions on fatigue properties, specimens heat treated in a vacuum followed by quenching and tempering (Specimen VQ) were prepared. Specimens VQ contained 0.07ppm hydrogen as compared to 0.80ppm hydrogen for conventional Specimens QT. Specimens VQ had a slightly smaller ODA than Specimens QT. Hydrogen was detected by a Secondary Ion Mass Spectrometer around the inclusion at fracture origin of Specimens QT and Specimens VQ. Thus, it can be concluded that the formation of ODA is closely related to hydrogen trapped by nonmetallic inclusions. Estimations of fatigue limit by the √<i>area</i> parameter model based on the original size of inclusions for fatigue limit defined for 10⁷ cycles are -10% unconservative. Considering the size of ODA into fatigue limit estimation, the √<i>area</i> parameter model can predict the mechanical fatigue threshold for small cracks without influence of hydrogen. The mechanism of duplex <i>S-N</i> curve is also discussed.

著者

左近 淑郎 伊達 新吾

出版者

社団法人日本材料学会

雑誌

材料 (ISSN:05145163)

巻号頁・発行日

vol.48, no.1, pp.30-37, 1999-01-15

参考文献数

9

被引用文献数

1

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The Nueber's rule which is a method widely used for estimating the elasto-plastic stress/strain concentration at notch tends to overestimate the strain concentration in general yield condition. This paper proposes to modify the application procedures of the Nueber's rule to improve the shortcoming . The modified procedures defined the nominal stress and strain by the sectional averaged-Mises equivalent stress and strain in order to take account of the multiaxial stress state in the notched section. This paper also describes the extensional application of the modified Neuber's rule to the creep loading and the deformation-controlled loading conditions which are important in the life evaluation of high temperature components. The effectiveness of the propsoed procedures are verified by the inelastic finite element analyses for notched plates. As the result, it is shown that the change of creep stress/strain concentaration with time can be estiamted by the method proposed. It can be also applied to the deformation-controlled loading based on the nominal equivalent stress estimated by considering the elastic follow-up behavior of the notched members.

著者

北川 正義

出版者

公益社団法人 日本材料学会

雑誌

材料 (ISSN:05145163)

巻号頁・発行日

vol.25, no.277, pp.979-983, 1976-10-15 (Released:2009-06-03)

参考文献数

15

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Craze and crack growth in polycarbonate, polyvinyl chloride and polymethyl methacrylate have been investigated under the presence of kerosene. The experiment for craze growth was carried out under the conditions of both constant rate loading and cyclic loading since the results under dead weight and step-wise loadings had previously been obtained. The delayed crack growth rate was investigated as a function of stress intensity factor.The experimental results were compared with the theoretical predictions derived from a model taking creep into account, which was proposed by the author.The results are summarized as follows.(1) The theory seems to hold also for the craze growth under constant rate and cyclic loadings.(2) The delayed crack growth may be classified in two types. One is the fibrous fracture type and the other is the quasi-brittle fracture type. The former type crack growth can be explained by the modified Knauss theory with the same time function as that of craze growth.

著者

浜島 拓美 飴山 惠 冨士 明良

出版者

社団法人日本材料学会

雑誌

材料 (ISSN:05145163)

巻号頁・発行日

vol.44, no.505, pp.1224-1230, 1995-10-15

被引用文献数

1 8

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This paper describes the microstructural change of a Ti/Al friction weld interface during heat treatment at 673K, 773K, and 873K. TEM/EDS observations of a commercially pure Al/Ti weld confirmed that only the Al_3Ti phase formed at the weld interface during heat treatment at 773K or 873K, while no intermetallic compound formed during heat treatment at 673K. The Al_3Ti phase was composed of fine equiaxed grains nucleated at the interface boundary and grown up to a few microns in diameter during the heat treatment. Although the Si content was less than 0.12 at% in the commercial Al/Ti weld, approximately 5 at% Si was solved into the Al_3Ti phase and a large amount of Si segregation, almost 20 at%, was detected at the Ti/Al_3Ti interface. No silicide formed during the heat treatment and the sugregation of Si was always observed. The observation of the specimen heat treated at 673K confirmed that Si segregation took place before the formation of the Al_3Ti phase. The faster growth rate of the Al_3Ti phase in the highly pure Al/Ti weld at 873K strongly suggested that the Si segregation retarded growth of the Al_3Ti phase. The growth rate of the Al_3Ti phase heat treated at 873K was in proportion to the square root of the holding time in the early stage of the heat treatment up to 3.6 ksec, while it was linearly proportional to the holding time in the latter stage of the heat treatment.

著者

西川 幸宏 太田 直秀 小升 雄一朗 高橋 雅興

出版者

The Society of Materials Science, Japan

雑誌

材料 (ISSN:05145163)

巻号頁・発行日

vol.60, no.1, pp.29-34, 2011

被引用文献数

7

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Three-dimensional real-space images of the carbon fiber (CF)/polymer composites were obtained by a high-contrast X-ray computerized tomography (CT). Since both CF and polymers do not include heavy atoms, CF has not been supposed to be suitable to X-ray CT observation. In this study, we used the X-ray CT apparatus which is designed to enhance the contrast of the materials consisting only of light-weight atoms. Besides the usage of the appropriate apparatus, the experimental conditions were found to be important : cutting the sample into a thin rod, and obtaining sufficient number of projections. In our case, we used 1mm × 1mm × 4mm sample, and 720 projections with 0.25 degree intervals in order to obtain the 3μm voxel resolution in the reconstructed three-dimensional images. Eventually, each CF in polystyrene was clearly visualized in three dimensions.

著者

岸本 喜久雄

出版者

社団法人日本材料学会

雑誌

材料 (ISSN:05145163)

巻号頁・発行日

vol.49, no.2, pp.238-244, 2000-02-15

参考文献数

19

被引用文献数

1 2

著者

坂西 明郎 田中 秀次郎

出版者

社団法人日本材料学会

雑誌

材料 (ISSN:05145163)

巻号頁・発行日

vol.17, no.175, pp.326-328, 1968-04-15

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Studies have been made of the dynamic viscoelastic properties of copolymers of styrene (S) and butadiene (B) in toluene (good solvent for both components) at 30.0℃. the polymers were prepared by the "living polymer" method with the same monomer feed ratio of S 61 mol % and B 39 mol %. The two were block copolymers with three sequences of B-S-B (BSB 1101) and S-B-S (SBS 1102), and the one was a random copolymer (SB 1103). The complex rigidities and the steady shear viscosities were measured by means of torsional crystals at the frequencies of 19.6kc, 39.2kc or 40.15kc, and 117.7kc, and a Ubbelohde dilution type viscometer respectively. The intrinsic rigidities and the generalized limiting relaxation times were obtained by extrapolation to zero concentration. The dimensionless functions of intrinsic rigidities were plotted logarithmically against the generalized angular frequencies together with the theoretical curves of Rouse (free-draining case) and Zimm (non-draining case). In these plots, the experimental points lie between the Rouse and the Zimm theory for the two block copolymers and closely on the Zimm theory for the random copolymer. It means that the random copolymer is nearly non-draining, and the block ones are partial-draining; BSB 1101 seems to exhibit the stronger draining effect than SBS 1102 toluene at 30.0℃. Since the draining effects correlate with the volume expansion, it may be suggested that the random copolymer has more compact conformation than the block sorts in such good solvent as toluene.

著者

川村 正晃

出版者

社団法人日本材料学会

雑誌

材料 (ISSN:05145163)

巻号頁・発行日

vol.28, no.313, pp.993-996, 1979-10-15

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The objective of this study is to clarify the effect of the chemical displacement reaction between Sn-Pb solder and ZnCl_2 binary system fluxes containing fluorides or iodides as a second component on the spreadability of Sn-Pb solder. The results obtained are summarized as follows. (1) when ZnCl_2 binary system fluxes containing fluorides such as AgF, BiF_3 and NiF_2 4H_2O or iodides such as AgI, BiI_3 and NiI_2・6H_2O were used, a remarkable chemical displacement reaction between Sn-Pb solder and the fluxes took place and the spread area of the solder with these fluxes was larger than that with pure ZnCl_2 flux. (2) When ZnCl_2 binary system fluxes containing fluorides such as ZnF_2, MnF_2, KF, NaF, LiF and BaF_2 or iodides such as ZnF_2 and CdF_2 Were used, the chemical displacement reaction hardly took place and the spread area was almost the same as that with pure ZnCl_2.

著者

布村 成具 山崎 泰広 大滝 秀治

出版者

社団法人日本材料学会

雑誌

材料 (ISSN:05145163)

巻号頁・発行日

vol.50, no.10, pp.1102-1107, 2001-10-15

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Fatigue characteristics are of fundamental importance when choosing a structural materials, especially when deciding upon the materials for reactor structure where long-term safety is primary importance. In this field, recently, the propagation behavior of mode II and mode III fatigue cracks has attracted special interest. The mode II and mode III fatigue testings involve greater difficulties compared with the mode I testing and the testing procedure has not been established. SS400 carbon steel was fatigue tested by a torsion fatigue testing machine. In the torsion test, fatigue cracks can propagate in all modes. To identify their behavior, surfaces of the specimen were observed by CCD camera and the behavior of surface cracks were recorded in a time-lapse video recorder which can record up to for 40 days. To reveal the morphology of the mode II and mode III Crack propagation, some of test interrupted specimens were sliced and observed by a two dimension measuring microscope. To investigate the crack morphology three dimension crack demonstrate computer program was developed. In the torsion test of plain surface specimen the mode II crack initiates first, but it transits to mode I in the early stage. However, according to the 3D view a large mode III crack propagates into inside in this stage. Persistent slip band like patterns were observed on the surface and the cross section of the fatigue cracked specimen and all mode III cracks propagate in the band. Some of them grew across the center of the specimen. The da/dN – ΔK diagram of the surface mode II fatigue crack propagation was compared with that of mode I by CT type specimen of the same material. Mode II Propagation rate agreed with mode I propagation rate where the stress intensity factor range was converted as ΔK_I= 2ΔK_II. It means that to design the structure by mode I crack propagation data alone may be acceptable under above conversion. To establish this relationship and to elucidate the behavior of mode III fatigue cracking, more investigations are required.