Journal of the Society of Materials Science, Japan
Online ISSN : 1880-7488
Print ISSN : 0514-5163
ISSN-L : 0514-5163
Volume 29 , Issue 327
Showing 1-15 articles out of 15 articles from the selected issue
  • Toshiaki KUROHA, Kazuaki YOSHIDA, Masao NISHIMURA
    1980 Volume 29 Issue 327 Pages 1155-1163
    Published: December 15, 1980
    Released: June 03, 2009
    JOURNALS FREE ACCESS
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  • Masao KAWANAKA, Shiomi KIKUCHI, Masao ADACHI
    1980 Volume 29 Issue 327 Pages 1164-1168
    Published: December 15, 1980
    Released: June 03, 2009
    JOURNALS FREE ACCESS
    High temperature deformation mechanisms of solid solution alloys is usually classified into 2 groups. One is the recovery rate control mechanism, such as the dislocation climb for example (class II), and the other is the dislocation glide mechanism (class I). This classification corresponds well with the difference in stress exponent between 5 and 3.
    Al-Mg alloy is well known as a typical alloy of class I and many investigations have been done on this alloy system.
    In the present study, single crystals of Al-Mg alloy were used in order to exclude the grain boundary effect. The results obtained are summarized as follows:
    (1) The stress exponent was about 3 independent of the initial orientation of tensile axis.
    (2) From the initial stage, the deformation proceeded by multiple glides.
    (3) The steady state stress level was determined by the number of the glide systems and the magnitude of the Schmid factors.
    (4) The apparent activation energy for the steady state deformation was about 105kJ/mol. This agrees well with the activation energy for the self-diffusion of Mg in Al.
    (5) The direct observation of deformed samples showed a very homogeneous distribution of dislocations.
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  • Tatsuo TOKUOKA
    1980 Volume 29 Issue 327 Pages 1169-1172
    Published: December 15, 1980
    Released: June 03, 2009
    JOURNALS FREE ACCESS
    The distortion of wave-form is investigated theoretically for the case, where the wave propagates in one-dimensional non-linear elastic materials. The constitutive equation is given by a non-linear stress-strain relation. The geometrical acoustics is applied and the wave displacement is assumed to be a product of amplitude and wave-form. The amplitude is assumed to vary gradually while wave-form is a function of eikonal which may vary rapidly. The pre-state is assumed to be homogeneous and static. From order-estimation it is possible to obtain the propagation velocity and the evolutional equation of the amplitude. The distortion of wave-form is found to depend on the first- and second-order derivatives of stress-strain relation. The wave-form may be flatten or sharpen.
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  • Masahiro MONKAWA, Shigeru NAGAKI, Tatsuo INOUE
    1980 Volume 29 Issue 327 Pages 1173-1179
    Published: December 15, 1980
    Released: June 03, 2009
    JOURNALS FREE ACCESS
    Constitutive relations of thermoelastic-plastic material undergoing phase trantsformation during heat treatment were developed on the basis of continuum thermodynamics. The interaction between temperature and metallic structures was carefully discussed to obtain the heat conduction equation including latent heat due to phase transformation.
    The structure and temperature distributions were numerically calculated by the finite element technique after determining the rate equation for each structure from the data of dilatation-temperature-time diagrams. Variations of stresses were also analyzed for solid cylinders of S45C and SCM-3 steels during quenching and tempering processes. The calculated results of transformation kinetics and residual stresses were compared with the experimental data measured by a microscope and X-ray diffraction method, respectively.
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  • Chiaki TANAKA, Toshio OHBA
    1980 Volume 29 Issue 327 Pages 1180-1186
    Published: December 15, 1980
    Released: June 03, 2009
    JOURNALS FREE ACCESS
    In order to clarify the effect of retightening on stress relaxation behavior for high temperature bolts used in a steam turbine, reloading stress relaxation tests have been carried out at 500°C and 550°C for 1Cr-0.5Mo-0.25V and 12Cr-1Mo-1W-0.25V bolting steels, respectively. The tests were made by repeating loadings up to thirty times at a specific value of initial stress for specific reloading time intervals. The initial stress at each loading was 30.3kgf/mm2 for 1Cr-0.5Mo-0.25V steel and 27.9kgf/mm2 for 12Cr-1Mo-1W-0.25V steel. The specific reloading time intervals were 24, 72, 240, and 720 hours.
    The reloading stress relaxation data obtained for both steels showed an increase in relaxation strength with the number of loadings, although they showed no increase in relaxation strength over a certain number of loadings. From the discussions on the dependence of residual stress, creep strain and testing time on relaxation plastic strain rate and the dependence of total strain on the relation between relaxation plastic strain rate and residual stress, it was shown that the strain hardening law, the time hardening law, and the constitutive equations for steady state creep could not be applied for the present data.
    This paper focused particularly on examination of relaxed stress versus accumulated plastic strain relations obtained from the data after specific reloading time at each number of loadings. Numerical analysis was made for these relations using an inductive procedure. An empirical equation to describe the reloading stress relaxation data at specific reloading time intervals for both steels was proposed as follows:
    σr0-atibNc
    where σr is the residual stress, σ0 is the initial stress, ti is the specific reloading time interval, N is the number of loading, and a, b, c are constants.
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  • Takashi KANNO, Masato KOBAYASHI, Kaoru UMEYA
    1980 Volume 29 Issue 327 Pages 1187-1193
    Published: December 15, 1980
    Released: June 03, 2009
    JOURNALS FREE ACCESS
    Extrusion tests have been carried out for non-aqueous dispersions of clay with adsorbed water under a variety of solid concentrations as well as the amounts of water adsorbed. The extrusion pressure can be divided into two components; one is the pressure drop in nozzle cone, which is independent on the extrusion speed, and the other is that in nozzle. From the rheological analysis of the dependence of the pressure drop in nozzle on the extrusion speed, flow properties of these dispersions were found to be represented approximately by the Bingham plastic model.
    With increasing a solid concentration, the yield stress increased exponentially, whereas the plastic viscosity remained unchanged above a critical solid concentration. This can be interpreted by the saturation of the effective volume fraction of particles including a part of dispersion medium immobilized within flocs, which may be resulted from a decrease in a void fraction between the particles. A further increase in the yield stress above the critical solid concentration can be attributed to an increase in a packing fraction of primary particles in flocs.
    The yield stress and the plastic viscosity were also dependent on the amount of water adsorbed, and showed maximum values at different amounts of water, respectively. These can be interpreted by considering the changes not only in a volume fraction of flocs but also in a packing fraction of primary particles in flocs, which may be resulted from the changes in the particle interactions associated with the cohesive force of water bridge as well as the repulsive force of the diffuse double layers between adjacent particles with water film. In addition, it is necessary to take into account the London-van der Waals' attractive force in order to interpret the rheological properties for the dispersions of dry powders.
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  • Shozo OKAZAKI, Yoshihiro YAMAZAKI, Mitsuru OKADA, Hiroshi NAKAMURA, Me ...
    1980 Volume 29 Issue 327 Pages 1194-1200
    Published: December 15, 1980
    Released: June 03, 2009
    JOURNALS FREE ACCESS
    A method for estimating the fatigue strength of smoothed and tufftrided specimens from the measurements of temperature rise in the specimens during rotating bending fatigue test was applied on three kinds of S15CK specimens with different tufftriding treatment time as well as on S45C and SCM3 specimens.
    The fatigue strengths of the tufftrided S15CK specimens with three different treated times were found to be estimatable by means of heat generation rate. It seems that the fatigue strength of the tufftrided S45C specimen can be estimated, because the temperature rise of the specimen had a similar tendency to that of the tufftrided S15CK specimens.
    However, this method for estimating the fatigue strength from heat generation rate was not applicable to the tufftrided SCM3 specimen, because the temperature rise of the specimen had a different tendency from those of both tufftrided low and middle carbon steels. Therefore, the fatigue strength of the specimen was estimated from the rate of mean temperature rise. However, the applicability of this method should be examined in future.
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  • Atsushi MURAKAMI, Tadatsugu YOSHIKI
    1980 Volume 29 Issue 327 Pages 1201-1207
    Published: December 15, 1980
    Released: June 03, 2009
    JOURNALS FREE ACCESS
    A study has been made on the tensile and fatigue properties of discontinuous carbon fiber reinforced ionomer composites oriented unidirectionally by hand-alignment technique.
    The fiber-matrix interfacial shearing strength calculated from the rule of mixture showed considerably lower value than that expected from the good adhesive ionomer matrix. The interfacial shearing strength decreased remarkably with increasing fiber length. It is considered that the fiber-matrix interfacial debonding can arise from the stress concentration at the fiber end, since the fiber overlaps are not perfectly in discontinuous fiber composites, and consequently, the interfacial shearing strength takes a very low value. It seems that the fiber-matrix contacts and the fiber overlaps decrease with increasing fiber length in discontinuous fiber composites oriented unidirectionally by hand-alignment technique.
    The low frequency fatigue tests on the unidirectionally oriented composites showed an excellent fatigue strength without braking for N=4×103 at 65% of ultimate tensile strength.
    The dynamic modulus of the fatigued Zn-type ionomer composite showed a 50% decrease against the virgin dynamic modulus at room temperature. The reduction of dynamic modulus may be related to the fiber-matrix debonding. On the other hand, the residual strength retained 90% of the virgin ultimate tensile strength. Even if the interfacial debonding occurs, the fiber could still carry load by the interfacial friction.
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  • Yasushi MIYANO, Manabu KANEMITSU, Takeshi KUNIO
    1980 Volume 29 Issue 327 Pages 1208-1214
    Published: December 15, 1980
    Released: June 03, 2009
    JOURNALS FREE ACCESS
    To investigate the time and temperature dependence of the interlaminar shear strength of CFRP (carbon fiber unidirectionally-reinforced plastics), interlaminar shear tests by a short beam method for CFRP and tensile tests for epoxy resin which was used as the matrix of CFRP were conducted at various constant temperatures and various constant strain rates.
    The results obtained are summarizd as follows:
    (1) Both the tensile strength of the matrix and the interlaminar shear strength of the CFRP showed remarkable dependence upon time and temperature.
    (2) The master curves of these strengths for both the matrix and CFRP could be constructed, using their thermo-rheologically simple properties. As for the time and temperature shift factor aT0 (T), they were not only identical, but also these aT0 (T) were similar to aT0 (T) of creep compliances of the CFRP and the matrix in the previous paper.
    (3) The appearance on fracture of the CFRP in the low temperature and high strain rate region was different from that in the high temperature and low strain rate region. In the former region, the interlaminar shear was observed after the buckling of fibers, but in the latter region, only the buckling of fibers was observed.
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  • Hidemitsu HOJO, Ken TSUDA, Cao MINH THAI
    1980 Volume 29 Issue 327 Pages 1215-1220
    Published: December 15, 1980
    Released: June 03, 2009
    JOURNALS FREE ACCESS
    The erosion mechanism of polymethyl methacrylate (PMMA) which is predominant at high angle of attack (>60deg.) has been studied by use of falling glass beads with an impact velocity of 12 to 36m/sec.
    In this mechanism, a characteristic ring-like damage pattern and transverse cracks were observed at or under the surface. Corresponding to each ring pattern, the cross section of damaged surface showed a step-like structure. Therefore, the damaged partis supposed to consist of many removed layers which have an equal step height of each ring. Based on these observations, new damage model was proposed. That is, the longitudinal cracks initiate from the surface, and then the transverse cracks initiate and propagate from the tip of longitudinal cracks. As the result of the intersection of these cracks, the material surrounded with cracks is removed. This makes the first ring. The damage process goes on similarly to deep direction.
    From the analysis of ring patterns and damage curves, the erosion rate was found to be proportional to the height of each layer and inversely proportional to the amount of impact particle during the incubation period. Accordingly, the design equation to estimate the erosion rate was proposed. The estimated results based on this new model agreed well with the experimental results.
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  • Yoshinori INADA, Norio YAGI
    1980 Volume 29 Issue 327 Pages 1221-1227
    Published: December 15, 1980
    Released: June 03, 2009
    JOURNALS FREE ACCESS
    In the case of underground storage of L. N. G., it is important to know the mechanical characteristics of rocks at low temperatures.
    In this study, the physical and the mechanical properties of dry and wet rocks were investigated at low temperatures. An easy method of estimating the strength of rock at low temperature based on the Protod'yakonov's method were examined.
    From the results of microscopic observation of mineral texture in rocks after low temperature treatment, the strength characteristics of rocks at low temperatures were explained.
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  • Yoshinori INADA, Norio YAGI
    1980 Volume 29 Issue 327 Pages 1228-1233
    Published: December 15, 1980
    Released: June 03, 2009
    JOURNALS FREE ACCESS
    Thermal diffusivity, the coefficient of thermal expansion and the velocity of ultrasonic waves which are necessary for calculation of thermal distribution and thermal stresses in a rock, were measured at low temperatures. Granite and Andesite were used as the rock samples. The measuring method of thermal diffusivity was developed in accordance with the application of Schmidt's theory.
    The main results obtained are as follows:
    (1) The thermal diffusivity of the wet rock specimens which have been submerged in water increased with lowering temperature, while that of the air dry specimens was nearly constant.
    (2) The tangential coefficient of thermal expansion of the rocks decreased with lowering temperature.
    (3) The dynamic Young's modulus calculated from the velocities of longitudinal and shear waves increased with lowering temperature.
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  • Kohei SAITO, Tetsuo FUKUZUMI, Isao ABE
    1980 Volume 29 Issue 327 Pages 1234-1239
    Published: December 15, 1980
    Released: June 03, 2009
    JOURNALS FREE ACCESS
    A method of estimating the filling capacity of tobacco shreds obtained by blending two kinds of tobacco leaves, which have different filling capacity, was investigated. Tobacco leaves used in this experiment were sampled from five stalk positions of a Flue-cured variety (BY4) and from a domestic Air-cured one (Matsukawa). After shredding, each sample from the Flue-cured variety was blended in various proportions with each sample from the Air-cured one, and the filling capacity of the blended shreds was measured.
    The essential results obtained were as follows:
    (1) The experimental value ((FC)bE) of filling capacity of blended shreds was represented by the following formula,
    (FC)bE=k1+k2M+k3M2,
    where M indicates the weight per cent of the Flue-cured in blended shreds. The variation of (FC)bE with M was found to be shown as a convex curve.
    (2) Being based on our previous finding that there was a high correlation between filling capacity of shreds and tensile elastic modulus of leaf, the variation of composite compressive elastic modulus (Eb) of blended shreds was calculated with the change of M, on the assumptions that tobacco shreds have perfect elasticity and that they are arranged in parallel with compressive force. It was found that the change of Eb with M was very similar to that of (FC)bE.
    (3) For practical use, the next linear formula ((FC)bA) could be applied to an estimation of filling capacity of blended shreds,
    (FC)bA={(FC)1×(M/100)}+{(FC)2×(100-M)/100},
    where (FC)1 and ((FC)2 indicate the filling capacity of the Flue-cured and that of the Air-cured, respectively. The maximum difference between (FC)bE and (FC)bA was less than 8% of the (FC)bA.
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  • Makoto KIKUKAWA, Masahiro JONO, Ken-ichi TANAKA, Yoshiyuki KONDO, Fumi ...
    1980 Volume 29 Issue 327 Pages 1240-1246
    Published: December 15, 1980
    Released: June 03, 2009
    JOURNALS FREE ACCESS
    Recently mini- or micro-computers are widely used even in the field of fatigue or fracture tests. The main purpose of their use, however, are automization of testing or measurements. In this study an automatic measurement system for fatigue tests has been developed by using mini-computers in consideration of detecting the parameters which control the fatigue process. The stressplastic strain hysteresis loop and the crack opening point were measured as the controlling factors during the fatigue process up to the crack initiation and during the crack propagation stage, respectively. The latter was detected by using the unloading elastic compliance method.
    Some attempts to improve the accuracy of measurements with the aid of soft-ware of computer programs are described.
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  • M. Fujiwara
    1980 Volume 29 Issue 327 Pages 1247-1253
    Published: December 15, 1980
    Released: June 03, 2009
    JOURNALS FREE ACCESS
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