材料
Online ISSN : 1880-7488
Print ISSN : 0514-5163
ISSN-L : 0514-5163
46 巻 , 12 号
選択された号の論文の15件中1~15を表示しています
  • 光分解性および生分解性プラスチックの分解挙動
    筏 英之
    1997 年 46 巻 12 号 p. 1347-1354
    発行日: 1997/12/15
    公開日: 2009/06/03
    ジャーナル フリー
  • 安井 義博, 安井 健真, 志澤 一之, 高橋 邦弘
    1997 年 46 巻 12 号 p. 1355-1361
    発行日: 1997/12/15
    公開日: 2009/06/03
    ジャーナル フリー
    The essence of macroscopic quantities in solid mechanics can be grasped by expressing these quantities with kinematic and mechanical quantities of atoms. In this paper, a method is proposed to obtain the microscopic expressions of macroscopic quantities. The concept of mesodomain is introduced in macroscopic materials so that the kinematic and mechanical quantities of atoms are averaged in this domain. The domains are associated with these averaged values and are regarded as infinitesimal elements of continua. Macroscopic balance equations and boundary conditions not only for stress but also for higher-order stresses are derived by using the principle of virtual power described with the above averaged values. The stress and higher-order stresses are expressed with the microscopic quantities which can be obtained from the molecular dynamics.
  • 倪 慶清
    1997 年 46 巻 12 号 p. 1362-1368
    発行日: 1997/12/15
    公開日: 2009/06/03
    ジャーナル フリー
    The buckling analysis of laminated composite plates compressed in two perpendicular directions is presented by using the pb-2 Ritz functions, which consist of the product of a basic function and a two dimensional polynomial function. The out-plane shear deformation is also taken into consideration in this analysis. It is shown that the convergence of solutions for the buckling load is good when the number of polynomials is more than 20. Numerical results are obtained for cross-ply and angle-ply laminated composite plates compressed in two perpendicular directions. The effects of material properties, plate aspect ratio, number of layers and lamination angle on buckling load are also investigated under simple supported, clamped edges and combined edge conditions. It is shown that the presented method considering the out-of-plane shear deformation can be widely used to analyze the buckling behavior of composite plates with general boundary conditions.
  • 瀧川 順庸, 幾原 雄一, 佐久間 健人
    1997 年 46 巻 12 号 p. 1369-1373
    発行日: 1997/12/15
    公開日: 2009/06/03
    ジャーナル フリー
    High-temperature tensile ductility of Al2O3 is much enhanced by spinel (MgO·1.5Al2O3) dispersion. However, the enhanced tensile ductility in Al2O3-20vol% spinel cannot be explained solely from grain size stability or reduction of flow stress. Detailed microstructural analysis reveals that the crack-like cavity growth rate during high-temperature deformation is more sluggish in Al2O3-20vol% spinel than in 0.1wt% MgO-doped single-phase Al2O3. The enhanced tensile ductility in Al2O3-20vol% spinel must be explained from the reduction of crack-like cavity growth rate during deformation. Since the grain boundaries in Al2O3-20vol% spinel mainly consist of Al2O3 grain boundaries and Al2O3/spinel interphase boundaries, the origin of the sluggish crack-like cavity growth in Al2O3-20vol% spinel is due to high resistivity against crack growth in Al2O3/spinel boundaries. Detailed TEM analysis clarifies that there is an epitaxial relationship between Al2O3 and spinel grains in many Al2O3/spinel interphase boundaries. These interphase boundaries are expected to have smaller interfacial energy, which must act to retard the crack-like cavity growth in spinel dispersed Al2O3.
  • 向井 将一, 小松 康宏, 上田 大輔, 坂根 政男, 大南 正瑛, 鶴井 孝文
    1997 年 46 巻 12 号 p. 1374-1380
    発行日: 1997/12/15
    公開日: 2009/06/03
    ジャーナル フリー
    This paper describes the development of triaxial tension creep machine. The developed machine can make equitriaxial tension creep experiments, and has a loading capacity of 49KN and the maximum temperature of 923K. Three dimensional finite element (FE) elastic-creep analyses were made to determine the shape and dimension of the specimen having uniform equi-triaxial stress distribution at the specimen center. The specimen shape determined by the FE analyses has 2.0mm groove radius at the notch. Equi-triaxial tension creep test was performed using Type 304 specimen at 923K. The uniaxial, equi-biaxial and equi-triaxial tension creep lives of Type 304 stainless steel at 923K were compared. Creep rupture time increased with increasing J1(=σxyz), so that the positive mean stress has an effect of increasing the rupture time. In the equi-triaxial tension stress condition, three principal strains of εx, εy and εz were smaller than in the uniaxial tension and equi-biaxial tension stressing conditions.
  • 山本 隆栄, 坂根 政男, 大南 正瑛, 山下 満男, 塩川 国夫
    1997 年 46 巻 12 号 p. 1381-1388
    発行日: 1997/12/15
    公開日: 2009/06/03
    ジャーナル フリー
    This paper describes the multiaxial low cycle fatigue (LCF) of 63Sn37Pb, 40Sn60Pb, 93.5Pb5Sn1.5Ag, 91.5Sn8.5Sb and 90Sn7.5Bi2Ag0.5Cu solders. Push-pull and reversed torsion LCF tests were carried out using the hollow tube specimens of the five kinds of solders at 313K. 63Sn37Pb and 40Sn60Pb solders had the largest LCF life compared at the same Mises' strain among the five solders. 90Sn7.5Bi2Ag0.5Cu had the smallest LCF life far smaller than the other solders. 93.5Pb5Sn1.5Ag and 91.5Sn8.5Sb solders had the intermediate LCF life. The Mises' strain was a suitable strain parameter for correlating the push-pull and reversed torsion lives but an energy parameter defined by the multiplication of stress and strain ranges gave a better correlation with the LCF life than Mises' strain. Many small cracks whose length was less than 100μm were initiated and propagated in the maximum shear direction in the push-pull and reversed torsion tests for all the solders excepting 90Sn7.5Bi2Ag0.5Cu. Main cracks whose length was around 10mm were found in the push-pull and reversed torsion tests for 93.5Pb5Sn1.5Ag, 91.5Sn8.5Sb and 90Sn7.5Bi2Ag0.5Cu. For 63Sn37Pb and 40Sn60Pb, main cracks were observed in the push-pull test, though no main crack was clearly found in the reversed torsion test. Variation of stress range with respect to number of cycles corresponded to the cracking behavior. A rapid drop in variation of stress range with respect to number of cycles was observed for the materials in which macroscopic crack propagation was found, but a gradual drop for the materials in which no macroscopic crack propagation was detected.
  • 後藤 真宏, D.M. KNOWLES, 皮籠石 紀雄, 西谷 弘信, 薬師寺 輝敏, 山本 隆栄
    1997 年 46 巻 12 号 p. 1389-1395
    発行日: 1997/12/15
    公開日: 2009/06/03
    ジャーナル フリー
    In order to clarify the fatigue behavior of Ni-base superalloy Udimet 720 Li, four point bending fatigue tests of plain specimens were carried out at room temperature. Initiation and propagation behavior of major cracks was observed by plastic replica technique. At the extremely early stage of cycling, cracking of TiN particles was generated. The cracked TiN particle always became the starting site of a micro crack. Though some particles embedded in the surface were cracked due to the stress cycling, the generation of cracking TiN particles was stopped before 30% of fatigue life. On the other hand, the growth rate of a small crack can be determined by a term σanl, not by ΔK. The n is a material constant and was 3.6. The relation between the fluctuation of dl/dN due to the microstructure and the small crack growth law was investigated. It was concluded that the dl/dN of microcracks can be evaluated based on the small crack growth law and dl/dN calculated from a smoothed crack growth curve.
  • 金澤 健二, 西島 敏
    1997 年 46 巻 12 号 p. 1396-1401
    発行日: 1997/12/15
    公開日: 2009/06/03
    ジャーナル フリー
    Elevated temperature, high-cycle fatigue behavior of low alloy steel SCMV 2 was discussed from viewpoints of the effect of oxidation on fracture mechanism by using the data published previously and some additional data. The results obtained are as follows:
    (1) Stepwise S-N curves were obtained for the fatigue data tested at 300 and 400°C. Surface fracture was dominant at the low cycle region. On the other hand, fish-eye fracture was observed at the high cycle region.
    (2) Fatigue limit was not observed at 400°C by the tests up to 109 cycles.
    (3) At the high cycle region tested at 300 and 400°C, surface fracture did not occur because of oxidation effect; nevertheless, fish-eye fracture occurred by the initiation and propagation processes of internal crack.
    (4) The temperature dependence of fatigue strength due to dynamic strain aging was not estimated by tensile strength but cyclic proof stress.
    (5) σayc-Nf curves, where σa, σyc and Nf are the stress amplitude, cyclic proof stress and number of cycles to failure, respectively, were classified into two cases independent of test temperature; surface fracture and internal fracture such as fish-eye pattern.
    (6) Fatigue behavior under internal fracture should be called ultra-high-cycle fatigue and be discussed in distinction from fatigue behavior under surface fracture which is called high-cycle fatigue.
  • 広瀬 幸雄, 夫 明煥, 松岡 秀明, 朴 栄哲
    1997 年 46 巻 12 号 p. 1402-1408
    発行日: 1997/12/15
    公開日: 2009/06/03
    ジャーナル フリー
    In order to study the influence of stress ratio and WC grain size, the characteristics of fatigue crack growth were investigated in WC-22wt.% Co cemented carbides with two different grain sizes of 3 and 6μm. Fatigue crack growth tests were carried out over a wide range of fatigue crack growth rate covering the threshold stress intensity factor range ΔKth. The fatigue tests were conducted at 10Hz and two stress ratios R=0.1 and 0.5 in laboratory air at room temperature using the 3-point bending specimens. It was found that the crack growth rate da/dN against the stress intensity factor range ΔK depended on stress ratio R. The crack growth rate plotted in terms of the effective stress intensity factor range ΔKeff (after allowing for crack closure) still exhibited the effect of microstructure. Fractographic examination revealed brittle fracture at R=0.1 and ductile fracture at R=0.5 in Co binder phase. The amount of Co phase transformation was closely related to the fatigue crack growth characteristics.
  • 小山 敦弘, 菅田 淳, 植松 美彦, 城野 政弘
    1997 年 46 巻 12 号 p. 1409-1414
    発行日: 1997/12/15
    公開日: 2009/06/03
    ジャーナル フリー
    In order to investigate the cyclic fatigue crack growth behavior of a gas-pressure-sintered silicon nitride under repeated two-step loadings, fatigue crack growth tests were carried out using compact type (CT) specimens. Crack length and macroscopic crack closure were measured using the unloading elastic compliance method. Regardless of repeated two-step loading patterns, the acceleration of fatigue crack growth rate was observed. High-level load execution was found to crash grain interlocking more severely and result in decrease of crack opening stress intensity factor, Kop, under low-level loadings. The fatigue crack growth acceleration behavior under repeated two-step loadings, where maximum load was kept constant, could be explained by crack closure behavior measured by the macroscopic method. However, under repeated two-step loadings where minimum load was kept constant, macroscopic crack closure behavior could account for the acceleration behavior qualitatively but not quantitatively.
  • 斉藤 満, 石森 広, 川村 満紀
    1997 年 46 巻 12 号 p. 1415-1421
    発行日: 1997/12/15
    公開日: 2009/06/03
    ジャーナル フリー
    The relationship between the alkali-silica reaction and the initial current intensity of mortars under the combined influence of NaCl and NaOH was investigated by using φ10×20cm cylindrical mortar specimens. The mortars were prepared with three types of aggregates, i.e., reactive andesite sand, siliceous sand, and Toyoura standard sand and an ordinary Portland cement. The water-cement ratio of all mortars was 0.50 and NaOH was added to the mortars at the stage of mixing. The initial current intensity of mortars was evaluated by applying a rapid chloride permeability test method (AASHTO T277). The results showed that reactive andesite sand mortars and Toyoura standard sand mortars had the lowest and the highest initial current intensity, respectively, among the mortars using three types of sands, when they were stored in a moist environment at>95% R.H. and immersed in 1N NaCl solution at 40°C for 4 weeks. These results indicate that the initial current intensity of mortars decreases with increasing alkali reactivity of sands used. It was also found that the initial current intensity of mortars at the age of 16 weeks decreased as the expansion increased except for siliceous sand mortars. The siliceous sand mortars having a relatively high equivalent percentage of Na2O exhibited large expansion and extremely high initial current intensity at the age of 16 weeks. The mechanism of expansion behavior of the mortars was also discussed.
  • 西村 六郎, 山川 宏二, G. K. HUBLER, R. M. LATANISION
    1997 年 46 巻 12 号 p. 1422-1428
    発行日: 1997/12/15
    公開日: 2009/06/03
    ジャーナル フリー
    The entry and transport of hydrogen in platinum-, arsenic-, lead- and antimony-implanted pure nickel specimens with a Fuence range of 1×1015 to 1×1017ions/cm2 have been investigated using an electrochemical permeation technique and a removal method of implanted layers to elucidate the chemical effect of implanted elements themselves and the physical effect causing through the process of ion implantation on hydrogen permeation behavior. It is found that As and Pt elements have the chemical effect on hydrogen permeation, whereas the other implanted elements show no chemical effect. The hydrogen permeation behavior of all the implanted specimens is influenced by the physical effect. Furthermore, the results obtained are discussed in more details in terms of the physical and chemical effects including catalytic effect, phase structure and so on.
  • 日下 一也, 英 崇夫, 富永 喜久雄, 阿尾 高広
    1997 年 46 巻 12 号 p. 1429-1435
    発行日: 1997/12/15
    公開日: 2009/06/03
    ジャーナル フリー
    Crystal orientation and residual stress development in AlN films deposited on BLC glass (Borosilicate glass; the termal stress expansion coefficient of which is nearly equal to that of AlN) substrate were investigated by the X-ray diffraction method. The AlN films were prepsred by an alternating planar magnetron sputtering system under the condition of constant substrate temperature, various nitrogen gas pressure between 0.17Pa and 1.1Pa and various switching time to alternate the anodic and catholic polarity of two target electrodes between 30sec and 600sec.
    The measurement of intensity from 00·2-diffraction showed that the c-axis orientation of AlN film was improved when the film was deposited at low nitrogen gas pressure below 0.5Pa and large switching time over 300sec. The tensile residual stresses wrer found in the films deposited at low nitrogen gas pressure below 0.3Pa or high nitrogen gas pressure over 0.8Pa and short switching time below 120sec.
  • 滝澤 秀一, 米浜 敬祐, 杉本 公一, 小林 光征
    1997 年 46 巻 12 号 p. 1436-1441
    発行日: 1997/12/15
    公開日: 2009/06/03
    ジャーナル フリー
    NiCrAlY/NiAl multi-layered coating was produced on SUS310S steel by means of mutual low pressure plasma spraying of NiCrAlY and Al powders which was accompanied with self propagating high-temperature synthesis (SHS) reaction of metal deposits. The NiAl layer contained Ni3Al particles and Cr2Al phase along the fine grain boundary. Also, Ni3Al was detected in the NiCrAlY layer with a small amount of NiAl particles. As the result, high hardness was obtained in both the layers, i.e., 650HV in NiAl layer and 450HV in NiCrAlY one at 673K. The structure of the multilayered coating changed hardly during annealing lower than 973K because enriched Cr at NiCrAlY/NiAl interface suppressed NiAl+Ni3Al→Ni5Al3 peritectoid reaction. The SHS reaction time of an compressed Al droplet in diameter of 50μm was calculated as 4.17×10-3 second.
  • 1. マイクロマテリアルの現代的ニーズと今後の展開
    駒井 謙治郎
    1997 年 46 巻 12 号 p. 1442-1447
    発行日: 1997/12/15
    公開日: 2009/06/03
    ジャーナル フリー
feedback
Top