Journal of the Society of Materials Science, Japan
Online ISSN : 1880-7488
Print ISSN : 0514-5163
ISSN-L : 0514-5163
Volume 40 , Issue 454
Showing 1-25 articles out of 25 articles from the selected issue
  • Takao HANABUSA, Michihiro TANI, Haruo FUJIWARA
    1991 Volume 40 Issue 454 Pages 790-796
    Published: July 15, 1991
    Released: June 03, 2009
    JOURNALS FREE ACCESS
    In the case of X-ray stress measurement of textured materials, the lattice strain distribution usually shows a nonlinear relation against sin2ψ because of the elastic anisotropy of crystals. In the present study, CrKα and MoKα characteristics X-rays were used for the investigation of cold-rolled low carbon steels. The non-linearity of sin2ψ diagram which is observed on the 211 diffraction was examined after plastic elongation as well as under elastic loading.
    The non-linearity of d-sin2ψ diagram for 211 diffraction by CrKα radiation was intensified with increasing elastic loading. Furthermore, the non-linearity was found to be more remarkably than that expected from the elastic anisotropy when the specimen was once suffered plastic elongation. On the other hand, it was found that the lattice strain distribution obtaind from the 732+651 diffraction by MoKα radiation showed good linearity in the sin2ψ diagram because of deep penetration depth of MoKα radiation and a high multiplicity factor of highly indexed diffraction plane. It was also found that the X-ray elastic constants for 732+651 diffraction clearly depended on the rolled ratio and sample orientation to the rolled direction of the specimen.
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  • Yasuo INOUE, Yukio SATOH, Kenji KASHIWAYA
    1991 Volume 40 Issue 454 Pages 797-803
    Published: July 15, 1991
    Released: June 03, 2009
    JOURNALS FREE ACCESS
    The behavior of plastic deformation under the running surface of various conventional line rails which differ in the accumulated service tonnage was analyzed mainly by the X-ray diffraction, considering the distribution and development of texture under the running surface of rail, the pattern of pole figure and the development of texture with an increase in the accumulated service tonnage, etc.From the analysis, the following results became clear by comparing it with the rolling contact fatigue test specimen and the Shinkansen rail.
    (1) The rolling contact fatigue in the conventional line is influenced by slip. The running surface of conventional line rail is subjected to larger maximum Hertz pressure than that of Shinkansen rail.
    (2) The development of texture well matches the increase in the accumulated service tonnage which corresponds to the number of cycles.
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  • Koichi AKITA, Shotaro KODAMA, Hiroshi MISAWA, Shogo TOBE
    1991 Volume 40 Issue 454 Pages 804-810
    Published: July 15, 1991
    Released: June 03, 2009
    JOURNALS FREE ACCESS
    Fatigue tests have been carried out under a constant load, decreasing load, constant stress intensity factor range and constant effective stress intensity factor range, using a Ni-Cr-Mo steel, JIS SNCM439. The residual stress and the half value breadth were measured on the fractured surface, and their correlations with stress intensity factors were investigated. Based on the experimental results, a model for residual stress development was proposed, which can predict the residual stress distribution on the fatigue fractured surface in X-ray fractography.
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  • Kazuyuki MATSUI, Yukio HIROSE, Akiyoshi CHADANI, Keisuke TANAKA
    1991 Volume 40 Issue 454 Pages 811-817
    Published: July 15, 1991
    Released: June 03, 2009
    JOURNALS FREE ACCESS
    Austempered Ductile Iron (ADI) is being used in highly stressed components, particularly in the automotive industry. It therefore becomes essential to understand the factors influencing the ductile and fatigue properties of this material.
    In the present paper, to obtain basic data of ADI, dynamic fracture toughness test and static fracture toughness test were conducted. And then X-ray fractographic technique was applied on the fracture surface made by these fracture toughness tests. The plastic zone size was determined from the distribution of the half value and residual stress near the fracture surface. These data obtained in the laboratory tests were used to estimate the dynamic fracture toughness parameter KId at actual fracture of machine parts.
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  • Kenji SUZUKI, Keisuke TANAKA
    1991 Volume 40 Issue 454 Pages 818-824
    Published: July 15, 1991
    Released: June 03, 2009
    JOURNALS FREE ACCESS
    Most of engineering ceramics are finished by grinding. Residual stresses and defects introduced into ceramics during grinding are two main factors which influence the strength of ground ceramics.
    In the present study, the specimens of pressureless sintered silicon nitride were ground by a diamond wheel of #170/200 grain size number in the longitudinal direction, and the bending strength perpendicular to the grinding direction was determined by four point bending. The residual stress measured by the X-ray method was compression on the ground surface and the compression zone extended about 20μm. The bending strength of ground specimen was lower than that of buffed standard specimens. The size of grinding flaws was estimated from the bending strength and the residual stress distribution by using the effective crack length model. The estimated flaw depth of 45μm agreed with the crack measured on the edge surface of the specimen.
    The bending strength of ground specimens was recovered by removing the surface layer by about 40μm. This recovery agreed with the model prediction based on the flaw depth estimated above.
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  • Shin-ichi OHYA, Shozaburo OHTA, Ken-ichi HASEGAWA, Shigekazu MISONO
    1991 Volume 40 Issue 454 Pages 825-831
    Published: July 15, 1991
    Released: June 03, 2009
    JOURNALS FREE ACCESS
    If a stress at any applied stress range during cyclic loading can be dynamically measured by means of X-rays, it will contribute to investigate the fatigue behaviors because the stress measured by X-rays is an actual stress under loading. In this study, we propose a new method to measure continuously an X-ray stress during cyclic loading based on the time-resolved tecnique and on the single-exposure technique (SET) by use of two position-sensitive proportional counters (PSPC).
    Single-exposure technique is available to measure a stress rapidly on a specimen which has a good linear sin2ψ relation. Therefore, we firstly developed a SET stress analyzer with dual PSPCs and a method to collect simultaneously two diffraction profiles at +η and -η sides in order to evaluate the stress determined by these diffraction angles as a mean value for the collection time of these profiles.Two PSPCs were connected in series each other, and X-ray signals from dual PSPCs were processed by only one multi-channel analyzer.
    We examined a practical method to measure continuously an X-ray stress during cyclic loading. A cycle of applied stress was divided by 16 stress ranges. In each cycle of applied stress, a couple of diffraction profiles at each stress range was collected for a short detection time, and was accumulated in the separate memory of the multi-channel analyzer. Such time-resolved collection was continuously carried out over all the preset stress ranges. This process in each stress cycle was repeated for definite cycles.
    In the application of this method, we verified that the actual stress at any applied stress range was measured as the algebraic sum of an applied stress and a residual stress when cyclic stresses were applied to a thin steel specimen at frequencies of 0.5, 2 and 8Hz.
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  • Tomoaki UTSUNOMIYA, Hidekazu NISHIZAWA, Kiyoshi KANETA, Tomohiro OZAWA
    1991 Volume 40 Issue 454 Pages 832-836
    Published: July 15, 1991
    Released: June 03, 2009
    JOURNALS FREE ACCESS
    This paper is concerned with the application of the law of approach to saturation magnetization for nondestructive evaluation (NDE) of stress in carbon steels. In our previous paper, we have deduced the formula m=A+Bσ for stress measurement based on the law, where m is a magnetic parameter in a high field region, σ is the applied stress, and A and B are constants. In this paper, we have examined the effect of carbon content ranging from 0% to 0.45% in the specimen on the constants A and B, and also the effect of the plastic strain up to 10%. The experiments show that the stress sensitivity B decreases almost linearly with increasing carbon content and it decreases with increasing plastic deformation, saturating in the region above 2% of the plastic strain.
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  • Takeji ABE, Toshimitsu NANBA, Makoto YAMADA
    1991 Volume 40 Issue 454 Pages 837-843
    Published: July 15, 1991
    Released: June 03, 2009
    JOURNALS FREE ACCESS
    Crystal grains in polycrystalline metals rotate during the plastic deformation by crystal slips, which results in the deformation textures of polycrystalline metals. In the present paper, the rotation of crystal due to slips was calculated adopting the constant stress model of polycrystals. The rate dependent type constitutive laws for crystalline materials that deform plastically by slips was used.Namely, a power law used by Hutchinson and an exponential type law proposed by Bodner were adopted as a relation between shear stress and shear strain-rate on the slip plane. It was pointed out that the parameters in the rate-type constitutive equations are related to the number of active slip systems. The relation between the rotation of crystals and these parameters, that is, the number of the active slip systems was clarified. A method was proposed to change the constant stress polycrystalline model toward the constant strain model by changing the parameter in the constitutive equation.
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  • Kinya OGAWA, Ayumu YAMADA
    1991 Volume 40 Issue 454 Pages 844-848
    Published: July 15, 1991
    Released: June 03, 2009
    JOURNALS FREE ACCESS
    With a prospect of wide technical applications, shape memory alloy steel developed recently is attracting large attention because of its excellent machinability and economical merit. In the present study, the strength and the shape memory effect of Fe-9Cr-5Ni-14Mn-6Si were clarified at temperatures from 208K to 423K and at strain rates from 10-4/sec to 4×102/sec. The results obtained are summarized as follows.
    (1) Independent of strain rate, a shape recovery ratio of 85 to 98% was obtained at temperatures from 273 to 293K.
    (2) The stress increased linearly with the logarithm of strain rate up to about 3% strain level.
    (3) The stress rose with temperature in the range of 273K to 370K, while it decreased with temperature outside of this range.
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  • Komei KASAHARA, Shigeru KOMUKAI
    1991 Volume 40 Issue 454 Pages 849-855
    Published: July 15, 1991
    Released: June 03, 2009
    JOURNALS FREE ACCESS
    Sliding wear properties of neat polychlorotrifluoroethylene against SUS 304 stainless steel surface, which are indispensable for predicting service life of gaskets used in the swivel-type joints on LNG loading arms, were investigated at the temperatures of the ambient (20°C) and LNG (-162°C). The effects of contact pressure, sliding speed and sliding distance on the amount of wear loss were analyzed by applying the Rhee-type wear equation. Through regression analysis, the Rhee-type wear equation for the stable sliding wear condition range was approximated as follows:
    (1) At the ambient temperature, 20°C:
    W1=2.09×10-7P2.35V3.38t1.44
    PV<20MPa·mm/sec
    (2) At LNG temperature, -162°C:
    W2=1.60×10-12P1.05V3.50t2.29
    PV<240MPa·mm/sec
    where W is the wear loss (mg/cm2), P is the nominal contact pressure (MPa), V is the sliding speed (mm/sec), t is the sliding time (min), and PV is the PV factor (MPa·mm/sec).
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  • Yoshikazu KURODA, Hisashi IZUMI, Hisakichi SUNADA, Kenzo FUKAURA
    1991 Volume 40 Issue 454 Pages 856-862
    Published: July 15, 1991
    Released: June 03, 2009
    JOURNALS FREE ACCESS
    Recently, sintered components are required to have higher strength. For instance, 17-4PH stainless steel, which is a martensitic age-hardened stainless steel or a hard working material, has found wide usage in aerospace application where high strength is required, and this material is known as one of the useful materials under severe service conditions of exposure.
    In this study, 17-4PH stainless steel bulk was produced by using the injection moulding method, and its mechanical properties and microstructures were compared with those of wrought 17-4PH stainless steel and sintered 18-8 stainless steel.
    The main results obtained are summarized as follows;
    (1) A martensitic high strength 17-4PH stainless steel was able to be produced by the injection moulding and sintering method.
    (2) The pore size and shape of the sintered 17-4PH stainless steel were smaller and closer to the sphericity than those of the sintered 18-8 stainless steel.
    (3) The optimum solution treatment temperature of the sintered 17-4PH stainless steel was 1183K, and it was lower about 150K than that of wrought 17-4PH stainless steel.
    (4) The age-hardening behavior of sintered 17-4PH stainless steel was the same as that of wrought 17-4PH stainless steel.
    (5) In the tensile strength, sintered and aged 17-4PH stainless steel was slightly inferior to wrought 17-4PH stainless steel, but it was twice as strong as sintered 18-8 stainless steel.
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  • Hideyuki HIRATA, Nagatoshi OKABE
    1991 Volume 40 Issue 454 Pages 863-868
    Published: July 15, 1991
    Released: June 03, 2009
    JOURNALS FREE ACCESS
    In order to study the applicability of a unified estimation method on evaluation of strength for porous Al2O3 ceramics used as refractories, various kinds of bending fracture tests, such as fast fracture, dynamic fatigue, cyclic fatigue and static fatigue tests, were carried out on 3 kinds of porous Al2O3 specimens. The main testing temperature conditions were room temp. and 1200°C in atmosphere.Other temperature conditions of 600, 800, 1000, 1100°C were added only in fast fracture tests. The stength data obtained were analyzed by use of a unified estimation method. The temperature dependence data were studied through Arrhenius plots. The results obtained were as follows:
    (1) The unified estimation method can be applied to the strength evaluation of porous Al2O3 at 1200°C as well as room temperature.
    (2) The temperature dependence of fracture strength was distinctly different below and above 1000°C. Above 1000°C, the fracture strength decreased rapidly with elevating temperature. But below 1000°C, the fracture strength was about constant up to 500°C and then increased slightly.
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  • Yoshihisa TANAKA, Chitoshi MASUDA, Toshihiko KURIYAMA
    1991 Volume 40 Issue 454 Pages 869-874
    Published: July 15, 1991
    Released: June 03, 2009
    JOURNALS FREE ACCESS
    In order to discuss the relationship between the fracture strength and defect size, tensile tests were performed on two kinds of boron fibers fabricated by CVD method, and their fracture surfaces were examined by a scanning electron microscope. The Weibull plots of tensile strength for boron fibers were divided into three regions; the lowest strength one, medium strength one and highest stength one. Fractography revealed that in the lowest strength region the defect size was large, while in the highest strength region no defect could be observed. The defect size was linearly related to the fracture strength, showing the applicability of fracture mechanics. The critical stress intensity factor for the surface defects was about twice larger than that for the inner defects observed near core tungsten fiber. This means that the difference of residual stress would be about 1.5GPa from near fiber surface to near core tungsten fiber.
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  • Hiroyuki KAWADA, Yutaka OCHI, Hiroshi SHIMANUKI, Ikuhiko HAYASHI
    1991 Volume 40 Issue 454 Pages 875-881
    Published: July 15, 1991
    Released: June 03, 2009
    JOURNALS FREE ACCESS
    Mode II fracture toughness tests of unidirectional GFRP were conducted using a four-point shear loading test method. This test method was a modified Iosipescu test method which was identified to be the most reliable one for obtaining a shear stress-strain relation in composite materials. In this study, a leverage ratio of the loading and a pre-crack length ratio of the specimen were examined to perform the fracture toughness tests. Fracture behavior of the unidirectional GFRP under shear loading was investigated through a fractographic observation. The results obtained are summarized as follows:
    (1) The four-point shear loading test method can be assessed at a simplified in-plane mode II fracture toughness test. To prevent premature failures without reinforcement attached to the specimen, it is necessary for the pre-crack length ratio, a/W to be larger than 0.3 under the definite leverage ratio.
    (2) The mode II fracture toughness evaluated in terms of stress intensity factors at the maximum load points was found to be dependent on the pre-crack length ratio.
    (3) The Hackle patterns were confirmed at a stable crack propagation region which are typical fracture traces on the matrix under the shear loading. The formation mechanism of the Hackle at different parts was investigated in detail, and then the physical meaning of the fracture toughness obtained in this experiment was discussed.
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  • Yoshiharu MUTOH, Kunihiro ICHIKAWA, Kohsoku NAGATA
    1991 Volume 40 Issue 454 Pages 882-888
    Published: July 15, 1991
    Released: June 03, 2009
    JOURNALS FREE ACCESS
    Fracture toughness tests of tungsten and tungsten-rhenium alloy were carried out at elevated temperatures. The effect of rhenium content on fracture toughness and the temperature dependence of fracture toughness were investigated. Fracture surface were observed in detail. Although the fracture toughnesses of three kinds of materials with rhenium of 0, 5 and 10wt% were almost identical at room temperature, the materials with higher rhenium content had the higher fracture toughness at elevated temperatures. The brittle-ductile transition similar to that of steels and the ductile-brittle transition at which recrystallization occurred, were observed for all three kinds of materials. With an increase of rhenium content, the brittle-ductile transition temperature decreased and the ductile-brittle transition temperature increased. A significant grain growth in the temperature range higher than the recrystallizing temperature, which was observed in the tungsten material without rhenium, was not found in the tungsten-rhenium alloy materials.
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  • Hitoshi UCHIDA, Shozo INOUE, Toshihiro OHIDO, Keiji KOTERAZAWA
    1991 Volume 40 Issue 454 Pages 889-894
    Published: July 15, 1991
    Released: June 03, 2009
    JOURNALS FREE ACCESS
    The stress corrosion cracking (SCC) of SUS 316 steel single crystals in a boiling 42% MgCl2 solution at 416K was investigated under the constant-loading conditions.
    Most of the threshold stress to SCC initiation which depended on the tensile axis orientation decreased with increasing Schmid factor in the primary slip system, and the cracking susceptibility increased accordingly. The threshold stress corresponded to 60-80% of the 0.2% yield stength (or critical resolved shear stress) in oil at 416K. In the [001]-oriented specimen, however, the cracking susceptibility was influenced by the primary slip directions: The more parallel they were to the top or side surface, the more the cracking susceptibility increased. Many cracks preferentially nucleated from the micro-pits (and/or corrosion grooves) formed along slip-steps, and grew along the ‹100›direction on the {210} plane in every type of specimens.
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  • Hitoshi UCHIDA, Shozo INOUE, Takashi KAMADA, Keiji KOTERAZAWA
    1991 Volume 40 Issue 454 Pages 895-900
    Published: July 15, 1991
    Released: June 03, 2009
    JOURNALS FREE ACCESS
    The susceptibility to stress corrosion cracking (SCC) and its potential dependence of pure titanium were investigated under the constant-loading condition. The SCC tests were conducted in CH3OH solutions containing HCl under given potentials at room temperature.
    The critical potential for SCC in CH3OH/0.4%HCl solution moved to the negative direction, and the susceptibility to SCC increased. The potential range for SCC corresponded with the active region in the potentiostatic anodic polarization diagram, and the test specimens were attacked by uneven general corrosion when the potential was moved to the positive direction. The fracture mode was also dependent on the above-mentioned potential range: The transition of intergranular to transgranular fracture was observed in the potential range of SCC whereas only intergranular fracture was found in that of general corrosion. The addition of Pt which impeded hydrogen absorption by promoting hydrogen evolution decreased the susceptibility to SCC.
    From the evidences introduced here, it is concluded that the intergranular and subsequent transgranular fracture are caused by the mechanical stress associated with the absorption of hydrogen generated by the dissolution reaction.
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  • Masaaki MATSUBARA, Akito NITTA, Kazuo KUWABARA
    1991 Volume 40 Issue 454 Pages 901-907
    Published: July 15, 1991
    Released: June 03, 2009
    JOURNALS FREE ACCESS
    The present paper describes an experimental study on the effect of environment on creep-fatigue strength of a single crystal Ni-base superalloy, CMSX-2. The creep-fatigue tests were carried out in vacuum, air and melted-salt. The creep-fatigue life of CMSX-2 decreased as corrosion environment became severer. This resulted from the difference in surface damage condition among the specimens tested in each environment. The creep-fatigue lives under PP and CC strain waveform conditions seemed to be more sensitive to environment than those under PC and CP conditions, similar to those of polycrystalline austenitic stainless steel.
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  • Hiroaki MORINAKA, Toru FUJII, Sadao AMIJIMA
    1991 Volume 40 Issue 454 Pages 908-913
    Published: July 15, 1991
    Released: June 03, 2009
    JOURNALS FREE ACCESS
    This paper presents the effect of loading and unloading duration on the fatigue damage process of plain woven GFRP. Specimens were subjected to three kinds of rectangle wave loading having different combinations of loading and unloading duration. All loading waves had the same maximum cyclic stress. Fatigue life, modulus decay, AE events and residual strength were measured. In-situ observation of internal damage of GFRP was conducted using an optical microscope with a video recording system.
    From the study, the following conclusions were obtained. The fatigue life is influenced by not only loading duration but also unloading duration. The fatigue life is short in the case that loading or unloading duration is long. Modulus decay in the fatigue process is affected by unloading duration, while it is not affected by loading duration. The residual strength is independent on both loading and unloading duration. In the case of short loading duration, debonding in the weft bundle becomes wide with an increase of number of cycles, but the rate is low. Few of debonding in the weft bundle propagate transversely and few AE events are detected in the case of short unloading duration regardless of loading duration. Both loading and unloading duration affect the growth mode of debonding in the weft bundle. These effects of loading and unloading duration on fatigue damage process may be explained by the difference in growth mode of debonding in the weft budle.
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  • Hiroto SUGAWARA, Akio OTSUKA, Yasuyuki ISHIHARA, Takehiko AMANO
    1991 Volume 40 Issue 454 Pages 914-920
    Published: July 15, 1991
    Released: June 03, 2009
    JOURNALS FREE ACCESS
    Static and cyclic fatigue tests were made under static tensile loading and tension-compression cyclic loading at the stress ratios of R=0 and -1 on silicon nitride-A, -B, glass ceramics and borosilicate glass. In these tests a specially designed apparatus was used. This apparatus was equipped with the device to minimize the load eccentricity, and it worked satisfactorily in performing cyclic tension-compression tests at any arbitrary stress ratio as well as static tensile tests. Crack growth tests were also made in order to obtain the crack growth rate, da/dt, as a function of stress intensity factor, K, in slow crack growth.
    The effects of cyclic stress on fatigue strength were investigated. Almost no effect of cyclic loading was observed on silicon nitride-A and borosilicate glass, while appreciable degradation in strength due to cyclic loading was observed on silicon nitride-B and glass ceramics. In static fatigue tests on smooth round bar tensile specimens, borosilicate glass showed the same fracture stress in air and in water, while, according to the results by crack growth tests, the da/dt in water showed appreciably higher values than that in air. K-V characteristics obtained from static fatigue tests (σ=const.) and constant stress rate tests (σ=const.) on round bar tensile specimens showed much larger values of da/dt than the values obtained from the tests n large cracks mentioned above. These results indicate that the crack growth characteristics of small cracks originated in smooth specimens are different from those obtained from crack growth tests on large cracks.
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  • Kazutaka FUJITA, Ryoichi KOTERAZAWA, Noboru TANIMOTO
    1991 Volume 40 Issue 454 Pages 921-926
    Published: July 15, 1991
    Released: June 03, 2009
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    The effect of mean stress on growing surface fatigue cracks in bending plates of annealed 0.20% C steel was studied under constant amplitude stressing and periodic overstressing. In constant amplitude stressing tests, the crack was semi-elliptic and had a smaller aspect ratio under compressive mean stress than under tensile mean stress. The crack propagation rate in depth direction was almost equal to that in surface direction for the same ΔK value when mean stress was tensile (R=0). When mean stress was compressive (R=-2), the former was lower than the latter. In periodic overstressing tests, the crack propagation rate became remarkably accelerated (several hundred times) as mean stress changing from tension to compression. Large acceleration (more than one hundred times) also occurred even in the case of tensile mean stress of overstress provided that it was large enough (R=0). The fracture surface morphology in most cases except small acceleration showed that the crack propagated in zigzag manner in the same way as the cases with large acceleration in through-thickness cracks reported previously.
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  • Ryoichi SHIKATA, Taiji YAMAMOTO, Takeshi SHIONO, Tomozo NISHIKAWA
    1991 Volume 40 Issue 454 Pages 927-933
    Published: July 15, 1991
    Released: June 03, 2009
    JOURNALS FREE ACCESS
    Y-TZP has both high sinterability and superior mechanical properties, but the fracture strength is degraded by annealing at such low temperatures as 100-300°C. In order to improve the heat degradation of TZP containing 3mol%-Y2O3, a fabrication technique for surface modification of TZP was developed. The method consists of infiltrating a porous powder compact with open porosity of about 53% by the application of Y(NO3)3 solution using a suitable brush and subsequently firing at 1400°C in air to decompose the infiltrant and to densify the powder compact.
    Y-TZP surface-modified by infiltration of Y(NO3)3 solution did not show the tetragonal to monoclinic zirconia transformation after aging in hot water of 200°C for 100 hours at all even through the examination by thin film X-ray diffraction. Therefore, this infiltration technique may prove to be very valuable when designing TZP for structural applications.
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  • Yasunari YOSHITOMI, Kuniteru OHTA, Jirou HARASE, Yozo SUGA
    1991 Volume 40 Issue 454 Pages 934-940
    Published: July 15, 1991
    Released: June 03, 2009
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    A method for measuring strain by analyzing the sharpness of first-order pseudo-Kikuchi line in Electron Channelling Pattern (ECP) was newly developed. The relative value of sharpness of first-order pseudo-Kikuchi line, which is the ratio of sharp ones in the first-order pseudo-Kikuchi lines, was used as a parameter of strain. Fe-3.25% Si alloy single crystal and polycrystal were used as the test specimens. Strain changes during their deformation and recrystallization were analyzed by this method. The main results obtained are as follows.
    (1) This method is useful for measuring strain in material with any crystal orientation.
    (2) The relative value of sharpness of first-order pseudo-Kikuchi line decreased as strain was increased. This method is useful for measuring strain less than 15% cold reduction.
    (3) The relative value of sharpness of first-order pseudo-Kikuchi lines was influenced by the initial crystal orientation before deformation. This phenomenon, recognized specially in the case of smaller strain, shows that accumulated strain is mainly influenced by the initial crystal orientation before deformation.
    (4) It is thought that this method is useful for analyzing crystal orientation dependence of accumulated strain and release of strain during recovery and recrystallization, as well as inhomogeneity of strain in the grain interior and near the grain boundary.
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  • Kazunori SAKAMOTO, Sayuri MURAMATSU, Keijiro TERASHITA
    1991 Volume 40 Issue 454 Pages 941-946
    Published: July 15, 1991
    Released: June 03, 2009
    JOURNALS FREE ACCESS
    Magnetic paint was produced by using magnetic powder subjected to inorganic or organic surface treatments, in order to make clear the influence of surface treatment exerted on the state of kneading and dispersion. The change of surface characteristic of magnetic powder was estimated from the heat of wetting for organic solvents and the amount of binder absoption. Also, the influences of the degree of surface treatment, water ratio of magnetic powder and the solubility parameter of organic solvent were studied.
    The state of kneading and dispersion of magnetic powder was evaluated by measuring the mixing torque, glossiness and magnetic recording properties of coated videotape.
    From the results, the effect of surface treatment for obtaining the well-dispersed state of magnetic powder was clarified.
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  • K. Takahashi
    1991 Volume 40 Issue 454 Pages 947-952
    Published: July 15, 1991
    Released: June 03, 2009
    JOURNALS FREE ACCESS
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