Journal of the Society of Materials Science, Japan
Online ISSN : 1880-7488
Print ISSN : 0514-5163
ISSN-L : 0514-5163
Volume 25 , Issue 273
Showing 1-13 articles out of 13 articles from the selected issue
  • Moriya OYANE, Teisuke SATO
    1976 Volume 25 Issue 273 Pages 501-508
    Published: June 15, 1976
    Released: June 03, 2009
    JOURNALS FREE ACCESS
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  • Hideo MINATA, Hiroshi NAKAMURA
    1976 Volume 25 Issue 273 Pages 509-515
    Published: June 15, 1976
    Released: June 03, 2009
    JOURNALS FREE ACCESS
    For prediction of the rupture life of metals subjected to reversed stressing of stress amplitude σa under a constant mean stress σm at elevated temperatures, the linear damage rule was adapted and its rupture life was analized by partitioning of parameter A, or the stress ratio σam. In the range of 0≤A≤1, an equivalent static stress σme for rupture life was determined by use of A and slope αt of rupture life curves based on σm. If rupture life curves of static creep are given, it is possible to predict approximately the rupture life curve of dynamic creep by calculation. In the range of 1≤A≤∞, an equivalent alternating stress σae for fatigue life was determined by using A and slope αt of completely reversed life curves based on σa. Therefore, a fatigue life curve for any mean stress will be predicted analytically from the completely reversed fatigue life curves.
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  • Osamu HAGA, Noriyuki HAYASHI, Kazuo KASUYA
    1976 Volume 25 Issue 273 Pages 516-520
    Published: June 15, 1976
    Released: June 03, 2009
    JOURNALS FREE ACCESS
    Tension, compression and combined tension-compression biaxial tests were performed on three types of glass fabric reinforced plastic laminates, and the applicability of an interaction formula was investigated. Based on these results a new combined tension-compression biaxial failure criterion have been derived. The results obtained are as follows;
    (1) The interaction formula can be used practically as the uniaxial failure criterion of glass fabric laminates when it is transformed into the equation containing tensile or compressive strength in the direction having an angle of 45 degree to one of the anisotropic axes.
    (2) In the case of closely woven plain fabrics, the interaction formula can be applied as the combined tension-compression biaxial failure criterion, but in the case of coarsely-woven plain fabrics, the calculated values do not agree well with the experimental results.
    (3) The values calculated according to the new combined tension-compression biaxial failure criterion agree fairly with the experimental results. When this criterion is applied to the case of uniaxial loading, the formula becomes the same as that of the uniaxial failure criterion given in (1).
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  • Tatsuo INOUE, Kenichi HARAGUCHI, Shigeto KIMURA
    1976 Volume 25 Issue 273 Pages 521-526
    Published: June 15, 1976
    Released: June 03, 2009
    JOURNALS FREE ACCESS
    Analyses of stresses in the process of heat treatment of steel, especially quenching and tempering, are made from the viewpoint of the theories of plasticity and creep.
    The effect of martensitic transformation during quenching is taken into consideration by introducing an unsteady thermal expansion coefficient which depends on both temperature and cooling rate. A method to predict the initiation of quenching crack is also presented.
    In order to analyze the process of tempering, the flow rule of creep is given by regarding the creep function as a potential, which is the function of stress, creep strain, temperature and time, and then an equilibrium equation is formulated by the finite element technique. It is concluded that this creep analysis is useful to predict the stress relief mechanism during the tempering process.
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  • Shuji TAIRA, Keisuke TANAKA, Keitaro TSUKUI, Masaaki SATO
    1976 Volume 25 Issue 273 Pages 527-534
    Published: June 15, 1976
    Released: June 03, 2009
    JOURNALS FREE ACCESS
    Silicone rubber with the silica content ranging from 15 to 48wt% was stretched under simple tensile loading. The experimental formula relating true stress to extension ratio was obtained and the constants in the stress-strain equation were correlated to the spring hardness of material. The internal structure of stretched silicone rubber was examined with the wide-angle X-ray method and the result was discussed in relation to its stress-strain behavior. The results obtained are summarized as follows:
    (1) For the range of extension ratio λ up to about two, the true stress was expressed as a function of λ as
    σ=3G(λ-1) or σ=2G[λ+1/(2√λ)]lnλ
    and the shear modulus G was related to spring hardness HS:
    G=0.121exp(0.51 HS).
    When λ is between 1.4 to 3.6, the true stress is given by
    σ=bλa,
    where a and b are constants related to HS as
    a=0.361lnHS+1.29 and b=0.31exp(0.048HS).
    (2) The increase in preferred orientation of the principal halo with extension ratio λ was found to be a sole function of λ, independent of the silica content. As stretching proceeded, the Bragg angle of the principal halo became larger in the direction perpendicular to the extension axis, while it showed no detectable change in the parallel direction. The half-value width of the halo decreased at a large value of λ. The degree of orientation in restretched rubber was smaller than that in the initial stretching when compared at the same λ-value.
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  • Ryoichi KOTERAZAWA, Daijiro SHIMO
    1976 Volume 25 Issue 273 Pages 535-541
    Published: June 15, 1976
    Released: June 03, 2009
    JOURNALS FREE ACCESS
    The effect of crystallographic orientation on fatigue crack propagation was studied with an aluminum alloy 2017-T4 by means of the etch pit technique. In the range of high crack propagation rate around 0.5 micron per cycle, the fracture surfaces were of typical striation type with moderate orientation dependence, {100} fracture surface -<110> propagation direction being somewhat preferred. As the propagation rate decreased into the range less than 0.05 micron per cycle, fracture surfaces changed to the brittle type with river-like or trough-like markings and with strong orientation dependence, {100}-<110> type fracture being predominant. High resolution fractographs revealed indications of ductile fracture such as striations and slip lines on the apparently brittle fracture. These observations indicate that a similar mechanism of fatigue crack propagation is operating in the whole range of propagation rate studied in spite of the different fracture appearances. A fracture mechanics calculation suggests that the transition of fracture morphology with propagation rate appears when the size of the crack tip plastic zone is comparable to the width of the trough-like markings which is one order smaller than the grain size of the test material.
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  • Hideo MINATA, Hiroshi NAKAMURA, Tomonobu OKADA
    1976 Volume 25 Issue 273 Pages 542-549
    Published: June 15, 1976
    Released: June 03, 2009
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    Fatigue tests of 7075 T6 aluminum alloy under constant mean stress σm in the range of 0.20≤A ≤∞(A=σam) were carried out by use of a testing machine of Schenck type. Also, fatigue tests under cyclic varying mean stress σm' were performed by using a new type of cyclic creep testing machine. The results obtained are as follows:
    (1) The strength diagram σam of stress cycle number N2 by use of fatigue test results under a constant mean stress σm, is shown nearly by a straight line. In the same way, the strength diagram of cycle number N2, by using fatigue test results under a cyclic varying mean stress σm', is shown nearly by a straight line. On the other hand, the strength diagram σm'-σm of cycle number N2, which was counted from summation tr of upper hold time in the test results of fatigue under only cyclic varying mean stress σm', is shown nearly by an ellipse.
    (2) Using the above three strength diagrams of same cycle number N2, the strength diagram of σmm'-σa is represented by an elliptic-cone.
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  • Hideo MINATA, Hiroshi NAKAMURA, Tomonobu OKADA
    1976 Volume 25 Issue 273 Pages 550-556
    Published: June 15, 1976
    Released: June 03, 2009
    JOURNALS FREE ACCESS
    The fatigue test of 7075 T6 aluminum alloy under constant mean stress σm in the range of 0.20 ≤A≤∞(Aam) was carried out by use of a testing machine of Schenck type. Also, the fatigue test under cyclic varying mean stress σm' was performed by a newly constructed cyclic creep testing machine. From these tests, the following results were obtained:
    (1) From the results of fatigue test under constant mean stress, the equivalent alternating stress σae was determined. The curve for the relation between σaea and A was found to be represented nearly by two linear lines with a junction point at A=0.5∼0.7. It was also found that the fatigue life curve in the range of A>0.5∼0.7 was nearly parallel to that under fully reversed stressing (A =∞) but in the range of A<0.5∼0.7 it was not parallel.
    (2) From the results of fatigue test under cyclic varying mean stress with secondary stress superimposed, the equivalent alternating stress σae was also determined and the curve for the relation between σaea and the stress ratio of σa to σm, A', was represented by two curved lines with a junction point at A'=0.5∼0.6. In the range of A'<0.5∼0.6 the curve was nearly a straight line, in the range of 0.5∼0.6<A'<0.8 it showed a convex toward the upper direction and in the range of A'>0.8 it was again nearly a straight line.
    (3) From the results of fatigue test under cyclic varying mean stress without secondary stress, the equivalent alternating mean stress Ye and the varying mean stress, Y=1/√2(σm'-σm), were determined. It was found that the relation between Ye/Y and the stress ratio A'(=Y/X) was represented by a similar curve given in (1) and (2).
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  • Jiro SAGA, Setuo MIYATA
    1976 Volume 25 Issue 273 Pages 557-563
    Published: June 15, 1976
    Released: June 03, 2009
    JOURNALS FREE ACCESS
    To study the effect of nickel content in iron-nickel alloys on the hydrogen-induced phenomena and susceptibility to hydrogen embrittlement, X-ray diffraction analysis and low strain rate tensile tests were performed for hydrogen charged iron-nickel alloys containing nickel 29∼50%.
    The results obtained are summarized as follows.
    (1) Hydrogen generated by elecrolytic charging reacts with iron-nickel alloys to form a solid solution and f. c. c. hydride.
    (2) The tendency for hydride formation increases with increasing nickel content.
    (3) Electrolytic charging of hydrogen into lower nickel alloys causes the same martensitic transformation as in the cases of cold working and subzero treatment.
    (4) Hydrogen existing in the form of solid solution suppresses the martensitic transformation in subzero treatment.
    (5) In 33% nickel alloy, no or little hydrogen embrittlement occurs. Alloys containing nickel either below or above 33% embrittled. This embrittlement in lower nickel alloys is due to martensite formation during hydrogen charging, tensile tests and subzero treatment, while in higher nickel alloys it is due to hydride formation.
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  • Eiji INO, Hidetsugu MORI, Tamotsu YAMATE
    1976 Volume 25 Issue 273 Pages 564-570
    Published: June 15, 1976
    Released: June 03, 2009
    JOURNALS FREE ACCESS
    As a part of the study on sintering, the effects of oxide additives on sintering of LaFeO3 compacts were investigated in air. The density, isothermal shrinkage and grain growth of sintered bodies were measured in relation to the sintering time, temperature and oxide additives. The lattice constants of the specimens were obtained by using the X-ray diffraction method.
    The results are summarized as follows.
    (1) The sintering of LaFeO3 was markedly promoted by the addition of TiO2 or MnO2 at the sintering temperature of 1450°C. The Cu2O addition caused a liquid phase sintering and promoted sintering.
    (2) The grain boundary diffusion mechanism was recognized during the initial sintering in the temperature range of the present experiment.
    (3) The grain size of LaFeO3 sintered bodies without any additives was shown to be smaller than those with 5mol% TiO2, ZnO, and MnO2 addition. The activation energy for grain growth obtained from the Arrhenius plot was found to be 150, 100, 93 and 103kcal/mol, respectively.
    (4) The lattice constants of 20mol% CaO additive specimen showed 0.036% increase along a axis and 0.127% decrease along c axis compared with those of LaFeO3 specimen.
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  • Sakichi OHGISHI, Hironobu ONO, Isamu TANAHASHI, Kunio ARAKI, Kenzo YOS ...
    1976 Volume 25 Issue 273 Pages 571-578
    Published: June 15, 1976
    Released: June 03, 2009
    JOURNALS FREE ACCESS
    This program was carried out to investigate the effect of various steel fibers on mechanical strength and deformation characteristics of fiber reinforced polymer-impregnated concrete (FPIC) polymerized by gamma-rays under water (dose rate: 1×106R/hr, 5MR). Tested steel fibers consist of four kinds of fibers each with 0.35mm diameter, piano wire, stainless steel, annealed stainless steel and low carbon steel (Table I). Fiber quantity and fiber length were varied within the range of F/C=5∼20% and length of 35mm or 150mm. Crimping effects of steel fiber which was trially formed to tridimensional waves (Fig. 1) were examined, and compared with normal straight fiber.
    Among the seven kinds of fiber examined, the straight piano wire was the most effective on increasing strength and plastic deformation of FPIC, and straight low carbon steel fiber was the most useful for fiber reinforced concrete with no polymer (FRC). However, the tempering process of stainless steel fiber had no beneficial effect (Fig. 5), and crimping of the fiber had the worse effects compared with normal straight one (Fig. 6).
    Steel fiber has a remarkable contribution to increase the impact strength of PIC, and straight piano wire gives the wide plastic range to the deformation of PIC and also gives large toughness Eu especially (Figs. 11 and 12). Ultimate flexural, compressive, tensile and Charpy's impact strengths and toughness of FPIC with F/C=15%, were as follows; σb=586, σc=2283, σt=180, σimp=277kg /cm2 and Eu=40.3kg·cm/cm2. These values are 7.2, 4.2, 3.0, 24.3 and 192 times as large as those of control samples, respectively.
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  • Kazumi MURAKAMI, Sadanori ITO, Yasunori MURAKAMI
    1976 Volume 25 Issue 273 Pages 579-583
    Published: June 15, 1976
    Released: June 03, 2009
    JOURNALS FREE ACCESS
    The moiré rosette method using two concentric, circular grids can be used as a mean of determining the principal strains and their directions in the case of complex strain fields. But the fundamental theory of this method has not been established yet.
    In this paper, it is shown that the discrimination of principal axes and the determination of principal directions can be done by forming fringes with several mismatch values.
    Further, a simple method for measuring the Poisson's ratio is presented, and its accuracy is discussed.
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  • T. Fujii
    1976 Volume 25 Issue 273 Pages 584-595
    Published: June 15, 1976
    Released: June 03, 2009
    JOURNALS FREE ACCESS
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