Journal of the Society of Materials Science, Japan
Online ISSN : 1880-7488
Print ISSN : 0514-5163
ISSN-L : 0514-5163
Search
Advanced search
OR
Browse
Search
Volume 52, Issue 7
Displaying 1-24 of 24 articles from this issue
Show all abstracts
    • |<
    • <
    • 1
    • >
    • >|
  • X-Ray Study on Residual Stress and Strength of TiC Thin Films Goated by CVD Method
    Keisuke TANAKA, Toshimasa ITO, Yoshiaki AKINIWA, Takahiro ISHII
    2003 Volume 52 Issue 7 Pages 738-743
    Published: July 15, 2003
    Released on J-STAGE: June 03, 2009
    DOIhttps://doi.org/10.2472/jsms.52.738
    JOURNAL FREE ACCESS
    Show abstractHide abstract
    Thin films of titanium carbide (TiC) were coated on various substrates such as cemented carbide (WC-Co) with different cobalt contents, ferritic and austenitic steels by the chemical vapor deposition (CVD) method. Thin films did not have strong texture. The residual stress in thin films was measured by the sin2Ψ method of X-ray stress measurement. The residual stress was tensile for WC-Co substrates, while compressive for steel substrates. The residual stress was nearly uniform within the film thickness for the cases of WC-Co substrates, while it had rather steep distribution for the cases of steel substrates. The magnitude of the residual stress increased in proportion to the mismatch of the coefficient of thermal expansion (CTE). The measured stress was more compressive than the prediction by CTE mismatch. Under the uniaxial applied stress, the stress in the thin film was biaxial because of the mismatch of Poisson's ratio, and increased in proportion to the applied strain as predicted from the elasticity relation of coated layers. At high applied strains, the stress in the thin film measured by X-rays did not increase because of cracking. The tensile fracture strength of TiC films on WC-Co substrates was found to be around 750 to 800MPa. This value is about twice the fracture strength of bulk materials.
    View full abstract
    Download PDF (1964K)
  • An Effect of Residual Stress on Mechanical Strength of TiN and TiCN Thin Films Having Fiber Texture due to Heat Treatment
    Masahide GOTOH, Toshihiko SASAKI, Yukio HIROSE
    2003 Volume 52 Issue 7 Pages 744-749
    Published: July 15, 2003
    Released on J-STAGE: June 03, 2009
    DOIhttps://doi.org/10.2472/jsms.52.744
    JOURNAL FREE ACCESS
    Show abstractHide abstract
    TiN and TiCN thin films are used as antiwear layer on parts such as metal cutting tools. It is reported that the thin films that are deposited ceramics and metals have preferred orientation, and that the residual stresses generate by the difference in the coefficients of thermal expansion between the thin films and the substrate. Tools coated with TiN and TiCN films are heated to high temperature during service due to the frictional heat. Under this condition, the texture and the residual stress should change due to the heat. In the material engineering, it is well known that the residual stress in the material affects the mechanical strength of the industrial products. The purpose of this study is to examine the effect of the residual stress on the mechanical strength of TiN and TiCN thin films having preferred orientation.
    In this study, specimens that are deposited TiN and TiCN respectively by Physical Vapor Deposition (PVD) were annealed in a furnace at temperature of 573K, 798K, 843K and 893K. Using X-ray diffraction technique, the crystallite orientation was evaluated by the pole figure and the crystallite orientation distribution function (ODF). The films exhibited {111} fiber texture. After that, the residual stress of thin films was measured using CoKα radiation with the two-exposure method at Ψ=39° and 75°. Since the relationship between the mechanical strength and the residual stress has not been revealed about the thin film materials, the effect of the residual stress on the mechanical strength of the TiN and TiCN thin films having preferred orientation was investigated by the dynamic hardness (DH) and the scratch test.
    As a result, although the ODF little changed due to the heat treatment, the residual compressive stress relaxed at higher temperatures than 573K. As for the hardness of thin films, the residual stress did not affect the hardness. However, the residual stress influenced the behavior of the scratch test. The abrasive wear and the micro cracks were decreased by highly residual compressive stress.
    View full abstract
    Download PDF (1899K)
  • Study on Elastic Constants and Residual Stress of Ceramic Hard Films
    Kenji KANEKO, Shigeru YONETANI, Manabu YASUOKA, Hiroyasu TOMODA
    2003 Volume 52 Issue 7 Pages 750-755
    Published: July 15, 2003
    Released on J-STAGE: June 03, 2009
    DOIhttps://doi.org/10.2472/jsms.52.750
    JOURNAL FREE ACCESS
    Show abstractHide abstract
    Recently, for the purpose of increasing the wear resistance of tools, the hard ceramics, TiC or TiN, are coated by the PVD technology on the surface. The physical properties of such deposited thin films differ from those of the bulk materials.
    In this study, the TiC or TiN films deposited to various thickness on the stainless steel substrate are prepared. The elastic constants of each film in the single and double layers are measured by the mechanical and the X-ray diffraction method. It is found that the elastic constants measured by the X-ray diffraction method are higher than that by the mechanical method. And then, the elastic modulus and compressive residual stress of each layer in the double-layer coatings are somewhat lower than that of single-layer coatings because of decrease in the texture and the internal strain.
    View full abstract
    Download PDF (1032K)
  • In-Situ Stress Measurement of Bond Coatings at High Temperature by High-Energy Synchrotron X-Rays
    Kenji SUZUKI, Keisuke TANAKA, Yoshiaki AKINIWA, Masashi KAWAMURA, Kozi ...
    2003 Volume 52 Issue 7 Pages 756-763
    Published: July 15, 2003
    Released on J-STAGE: June 03, 2009
    DOIhttps://doi.org/10.2472/jsms.52.756
    JOURNAL FREE ACCESS
    Show abstractHide abstract
    High-energy X-rays from a synchrotron radiation source, SPring-8, are available to obtain the microstructural information at deep positions inside the materials, because of its large penetration depth. Using the high-energy X-rays with an energy level of about 73keV, the internal stress in the bond coating was measured through the top coating in the thermal barrier coatings (TBCs) which consisted of a zirconia top coat with thickness of 0.24mm and a NiCoCrAlY bond coat with thickness of 0.2mm. A furnace, which could heat up the specimen up to 1473K was developed for the purpose of the in-situ stress measurement of the TBC in the goniometer at Beam Line BL02B1 of SPring-8. The diffraction of Ni3Al-311 from the bond coat obtained through the top coat with about 0.24mm thickness was strong enough for stress determination. The internal stress in the bond coating was measured at the room temperature, 773K, 1073K and 1373K. The internal stress in the bond coat at a room temperature was tensile, and it was decreased with increase in temperature. At 1073K or higher, the internal stress in the bond coat was released due to softening of the bond coat. The change of internal stresses in the bond coat with temperatures was explained by thermal mismatch of expansion between top and bond coats.
    View full abstract
    Download PDF (3789K)
  • Evaluation of Residual Stress Distribution in Shot-Peened Steel by Synchrotron Radiation
    Yoshiaki AKINIWA, Keisuke TANAKA, Kenji SUZUKI, Etsuya YANASE, Koji NI ...
    2003 Volume 52 Issue 7 Pages 764-769
    Published: July 15, 2003
    Released on J-STAGE: June 03, 2009
    DOIhttps://doi.org/10.2472/jsms.52.764
    JOURNAL FREE ACCESS
    Show abstractHide abstract
    The in-depth distribution of residual stresses in shot-peened steels was measured by using high energy X-rays from a synchrotron radiation source. The relation between the 2θ and sin2ψ was obtained with the side-inclination method (ψ diffractometer). The distribution of residual stresses was first evaluated by the nonlinearity of the sin2ψ diagram by a simplex method. The estimated stress agreed with the distribution determined through the sin2ψ method by using Cr-Kα radiation combined with the conventional surface removal method. A new method was proposed to estimate the stress value of the distributed residual stress. The new method was a combination of the sideinclination method and the iso-inclination method (ω diffractometer) to maintain the penetration depth constant. The sin2ψ diagram could be approximated by the linear relationship. The evaluated stress distribution agreed well with the distribution obtained by the surface removal method.
    View full abstract
    Download PDF (1654K)
  • Evaluation of Phase Stresses of Al2O3/YAG Binary MGC by Synchrotron Radiation
    Residual Stress States and Stress Behavior of YAG Phase
    Hiroshi SUZUKI, Koichi AKITA, Yasuo YOSHIOKA, Yoshiharu WAKU, Hiroshi ...
    2003 Volume 52 Issue 7 Pages 770-775
    Published: July 15, 2003
    Released on J-STAGE: June 03, 2009
    DOIhttps://doi.org/10.2472/jsms.52.770
    JOURNAL FREE ACCESS
    Show abstractHide abstract
    Melt Growth Composite material (MGC) consists of multiple single crystal with fine entangled in three dimensional network structures. The MGCs are thermally stable and have higher creep resistance. Furthermore, the flexural strength at room temperature can be maintained almost up to the melting point. In this study, in order to discuss the generation mechanism of residual stress in an Al2O3/Y3Al5O12 (YAG) binary MGC, the residual stresses of YAG phase were measured by X-rays from synchrotron radiation source. We used a method for stress determination of single crystal by using a position sensitive proportional counter (PSPC) system and a specimen-oscillating device. Lattice strains of {4 6 10} in the YAG phase were measured. The residual stresses were from 40 to 120MPa in tension in the longitudinal direction which corresponds to the solidification direction, 80MPa in compression in the thickness direction, and 70MPa in tension in the width direction. Since the thermal expansion behavior of Al2O3 is anisotropy in the crystallographic direction, the residual stress states of MGC indicated the anisotropy. However, only the mismatch of the thermal expansion coefficient between each phase cannot lead the reason of the generation mechanism of the residual stresses. The Young's modulus, which was mechanically measured using a four-point bending method, was about 349±3GPa, which is equal to the Young's modulus calculated by the Voigt model. The X-ray stresses on YAG phase under applied stressing were equivalent with the calculated stresses based on the Voigt model. Therefore, the Voigt model may be applied in the stress behavior on the Al2O3/YAG binary MGC.
    View full abstract
    Download PDF (3440K)
  • Estimate Technique for Circumferential Distributions of Residual Stresses on Cylindrical Component Surfaces by X-Ray Stress Measurement
    Taizo OGURI, Kazuo MURATA, Yoshihiro SATO
    2003 Volume 52 Issue 7 Pages 776-782
    Published: July 15, 2003
    Released on J-STAGE: June 03, 2009
    DOIhttps://doi.org/10.2472/jsms.52.776
    JOURNAL FREE ACCESS
    Show abstractHide abstract
    A new technique utilizing the X-ray diffraction is proposed to estimate the circumferential distributions of residual stresses on convex/concave cylindrical surfaces. This technique requires neither tilting X-ray beams in the circumferential direction in which the X-ray incident angle tends to be limited nor adjusting the normal of the irradiation area to the reference axis of the ψ angle. The circumferential distribution of the circumferential stress and that of the axial stress are estimated from the geometrically modulated diffraction angles at ψ=0 (deg) and the geometrically modulated axial stresses measured at the inclined points by performing the stress measurement on multiple inclined points of the cylindrical surfaces under the configuration of the axial stress measurement using the iso-inclination scanning method. This estimate technique was applied to two specimens of round bars; one has circumferential distributions of the residual stresses, and the other has almost uniform stresses. The distribution functions of the residual stresses were expanded to a couple of Fourier series, and the coefficients of them were determined so as to satisfy the geometrically modulated quantities mentioned above. The estimated distributions of the residual stresses were in practically good agreement with the actual ones.
    View full abstract
    Download PDF (1249K)
  • Application of MA-SPS Method for Fabrication of Microstructures Using LIGA Process
    Naoki MIYANO, Kazunori TAGAYA, Kazunori KAWASE, Kei AMEYAMA, Susumu SU ...
    2003 Volume 52 Issue 7 Pages 783-788
    Published: July 15, 2003
    Released on J-STAGE: June 03, 2009
    DOIhttps://doi.org/10.2472/jsms.52.783
    JOURNAL FREE ACCESS
    Show abstractHide abstract
    Reproduction techniques, like an injection molding or micro-powder injection metallurgy or embossing, are one of the methods which provide microstructures of wide variety of materials and of the production method as a application of LIGA process. Metals and ceramics become of increasing importance to microsystem technology in terms of mechanical properties and physical functions. In this study, we develop a new process using LIGA mold which is able to cast a microstructure of alloys or ceramics using Spark Plasma Sintering (SPS) machine. In addition, the powder of alloys is made by mechanical alloying (MA) method. In this report, a spring structure of Ti-Ni-Cu shape memory alloy was produced by way of trial. As the results, it was found this LIGA-MA-SPS process became effective technique.
    View full abstract
    Download PDF (5189K)
  • Effect of Crystal Grain Size on Strain Localization
    Observation of Surface Temperature Distribution under Deformation
    Hidetoshi SAKAMOTO, Jian SHI, Eiji NAKAMACHI
    2003 Volume 52 Issue 7 Pages 789-794
    Published: July 15, 2003
    Released on J-STAGE: June 03, 2009
    DOIhttps://doi.org/10.2472/jsms.52.789
    JOURNAL FREE ACCESS
    Show abstractHide abstract
    The stress-strain characteristics and plastic behaviors of Aluminum alloy were examined by tensile test and infrared thermo-viewer. Al-Mg FCC polycrystalline sheet plates (crystal grain size d=12, 42, 3000μm) were used. The effect of grain size and initial orientation distribution on the harding evolution, strain localization and crystal rotation by using X-ray diffraction and ODF analyses. Furthermore, the behaviors of the plastic deformation and the fracture were continuously observed by using the thermo-viewer in order to make clear the effect of the different crystal grain sizes on macroscopic local plastic behavior. The results obtained in this study are summarized as follows; (1) The strength level increase with decreasing crystal grain size, (2) The lager crystal grain, the quicker the strain localization occurs, (3) By making differential thermal images, a macroscopic local plastic deformation can be estimated.
    View full abstract
    Download PDF (4178K)
  • Stress Concentration Formula Useful for Any Dimensions of Notches
    Effect of Notch Opening Angle on the Stress Concentration Factor
    Yasushi TAKASE, Nao-Aki NODA, Yan GAO, Tomokazu TAKEMOTO
    2003 Volume 52 Issue 7 Pages 795-800
    Published: July 15, 2003
    Released on J-STAGE: June 03, 2009
    DOIhttps://doi.org/10.2472/jsms.52.795
    JOURNAL FREE ACCESS
    Show abstractHide abstract
    In our previous studies, a set of convienient formulas useful for any dimensions of notches in a round specimen were proposed for a notch opening angle of 60 degree. In this study the effect of notch opening angle on the stress concentration factor is considered. First, for the limiting cases of shallow notches, the body force method is used to calculate the SCFs with varying the opening angle from 0 to 90 degree; then, the formulas are obtained as Kts for any root radius. Second, for the limiting cases of deep notches, the body force method is used to calculate the SCFs with varying the opening angle from 0 to 90; then, the formulas are obtained as Ktd for any root radius. Third, for general notches the effect of opening angle is considered. Finally, a set of convenient formulas useful for any shape of notch in a round test specimen are proposed for the opening angle from 0 to 90 degree. The formulas yield SCFs with less than 1% error for any shape of notch in most cases under tension.
    View full abstract
    Download PDF (1167K)
  • Temperature and Stress during Induction Hardening Process of Gears by Dual Frequency Method
    Kouitsu MIYACHIKA, Satoshi ODA, Hajime TSUBOI, Hiroshige FUJIO
    2003 Volume 52 Issue 7 Pages 801-806
    Published: July 15, 2003
    Released on J-STAGE: June 03, 2009
    DOIhttps://doi.org/10.2472/jsms.52.801
    JOURNAL FREE ACCESS
    Show abstractHide abstract
    This paper presents a study on temperature and stress during the induction hardening process of gears by the dual frequency method. An electromagnetic field analysis, a heat conduction analysis and an elastic-plastic stress analysis during the single and dual frequency induction heating and water cooling processes of gears were carried out by the two-dimensional finite-element method (FEM), considering changes of the magnetic permeability, the resistivity, the thermal expansion coefficient and the yield stress with the temperature. The temperature and stress changes during the induction hardening process by the dual frequency method and the residual stress due to the induction hardening were examined, and compared with those by the single frequency method. The validity of the dual frequency method for the residual stress due to the induction hardening of gears was confirmed.
    View full abstract
    Download PDF (1050K)
  • Influence of Thermal Aging on Interface Delamination of Thermal Barrier Coatings
    Takamasa ONOKI, Tetsuro TONOMORI, Kazuhiro OGAWA, Toshiyuki HASHIDA, T ...
    2003 Volume 52 Issue 7 Pages 807-814
    Published: July 15, 2003
    Released on J-STAGE: June 03, 2009
    DOIhttps://doi.org/10.2472/jsms.52.807
    JOURNAL FREE ACCESS
    Show abstractHide abstract
    Knowledge of the degradation mode in thermal barrier coatings (TBCs) is a prerequisite for the prediction of their remaining life of gas turbine blades. This paper describes the effects of thermal aging on the microstructure in a YSZ-based thermal barrier coating system deposited on Ni based superalloy substrates. The heat treatment of the TBC specimens were conducted at 1373K for 100h, 500h and 1000h in air for thermal aging. The thermally aged coating system had thermally grown oxide (TGO) layer between the substrate and the TBC. TGO consisted of not only alumina but also other oxides. This oxide layer that named mixed oxides (MO) is composed of Ni, Co, Cr and O. Double cantilever beam (DCB) tests and 4 point bending tests were carried out in order to evaluate the TBC/substrate interface strength. The interface strength depended on the period of thermal aging in both type of tests. The interface strength increased initially up to the aging time of 100h, and then decreased drastically for the longer aging time. In DCB tests, crack propagated in the middle of YSZ layer for the thermally aged specimens, whereas delamination took place close to the YSZ-bondcoat interface in the unheated specimens. In 4 point bending tests, crack propagated along the interface between TBC and substrate. These results suggested that the interface strength depended on not only the formation of oxides but also the fracture properties of the top coatings.
    View full abstract
    Download PDF (4865K)
  • Fracture Criterion of Single Fiber-Composite under Thermal and Tensile Loadings Based on Energy Release Rate
    Tadanobu INOUE, Shojiro OCHIAI, Masaki HOJO, Kotobu NAGAI
    2003 Volume 52 Issue 7 Pages 815-820
    Published: July 15, 2003
    Released on J-STAGE: June 03, 2009
    DOIhttps://doi.org/10.2472/jsms.52.815
    JOURNAL FREE ACCESS
    Show abstractHide abstract
    A crack terminating at an interface in fiber reinforced composites may advance by either penetrating through the interface or deflecting into the interface. To describe such a phenomenon, the energy release rate based on the interfacial mechanics is used in this work as the fracture criterion. The energy release rates for the crack deflecting into the interface and the crack penetrating the interface depend on the branch crack length Δa, which is arbitrarily small compared to the length of the main crack. When loading condition is a tensile load, the ratio of those energy release rates is independent of Δa. However, the ratio depends on Δa in case of thermal loading condition. A relation between the ratio and the stiffness ratio of the components (fiber and matrix) is investigated in cases of two loading conditions, and the debonding conditions are shown. The results can be used for determination of the range of interface toughness relative to fiber one, to ensure the cracks to be deflected into the interface for prevention of catastrophic fracture.
    View full abstract
    Download PDF (1154K)
  • Fatigue Crack Propagation in Magnesium Alloy AZ31 Rolled Plate
    Keiro TOKAJI, Mitsutoshi KAMAKURA, Norihiko HASEGAWA, Yasuki TSUBOI
    2003 Volume 52 Issue 7 Pages 821-826
    Published: July 15, 2003
    Released on J-STAGE: June 03, 2009
    DOIhttps://doi.org/10.2472/jsms.52.821
    JOURNAL FREE ACCESS
    Show abstractHide abstract
    This paper describes the fatigue crack propagation (FCP) characteristics in magnesium alloy AZ31 rolled plate. FCP experiments have been performed at stress ratios, R, of 0.05 and 0.7 in laboratory air at ambient temperature using CT specimens with two different orientations of L-T and T-L. The effects of orientation and stress ratio and fracture mechanism were discussed on the basis of crack closure measurement and fracture surface analysis. Regardless of orientation, the relationship between FCP rate and stress intensity factor at R=0.05 consisted of two parts with different slops, which became much more remarkable when FCP rates were characterized in terms of the effective stress intensity factor. This was attributed to fracture mechanism transition because the fracture mechanisms operated were different above and below a stress intensity factor where the slops changed. After allowing for crack closure, a slight difference in FCP behaviour between both orientations and a clear stress ratio dependence of FCP rate were still seen, but these could be due to some problems in measuring crack closure, because fracture mechanism was not affected by orientation and stress ratio. The intrinsic FCP resistance of the present Mg alloy was found to be inferior to that of other materials such as aluminium alloys and pure titanium.
    View full abstract
    Download PDF (2717K)
  • Fatigue Behavior of Wood-Based Panels for Structural Use under Shear-Loading through Thickness
    Yasutoshi SASAKI, Katsuyuki ANDO, Mariko YAMASAKI, Takayuki ITO, Shige ...
    2003 Volume 52 Issue 7 Pages 827-832
    Published: July 15, 2003
    Released on J-STAGE: June 03, 2009
    DOIhttps://doi.org/10.2472/jsms.52.827
    JOURNAL FREE ACCESS
    Show abstractHide abstract
    Wood-based panels are widely used in the bearing walls and complex beams as the resistant element against shear force. As shear forces such as frequent earthquakes and typhoons work on them during their service life, the strength properties are predicted to reduce. Fatigue behavior of these panels generated by these natural disasters must be considered in determining safe design loads and for predicting service life of the panels. Fatigue tests of wood-based panels (Plywood; PW and Oriented strand board; OSB) were performed under cyclic shear-loading through thickness. A linear relationship between stress level and logarithm of the number of cycles to failure up to 106cycles existed. Shear rigidity kept its initial value at the beginning of cyclic loading and reduced gradually its value toward the fatigue life. A marked increase in the maximum shear strain was observed just before the fatigue life. These fatigue behavior showed differences between PW and OSB just before the fatigue life owing to their elemental constitutions. Prediction of the fatigue life was made based on the cyclic creep of the maximum shear strain.
    View full abstract
    Download PDF (2556K)
  • Effect of Strain Waveform on Low-Cycle Fatigue Life of Ti-6Al-4V Alloy at Elevated Temperature
    Seiichi NISHINO, Kazuaki SHIOZAWA, Tomonori OHKUMA
    2003 Volume 52 Issue 7 Pages 833-837
    Published: July 15, 2003
    Released on J-STAGE: June 03, 2009
    DOIhttps://doi.org/10.2472/jsms.52.833
    JOURNAL FREE ACCESS
    Show abstractHide abstract
    The effect of strain waveform on low-cycle fatigue strength of Ti-6Al-4V alloy at elevated temperature was studied. Total strain controlled low-cycle fatigue tests were carried out using a smooth specimen with triangular and tension-hold or compression hold trapezoidal waveforms at 773K in air. From the experimental results, low-cycle fatigue life decreased by introducing a hold period as compared with that using a triangular waveform. The fatigue life of the compression-hold tests decreased as compared with tension-hold tests. The low-cycle fatigue life of Ti-6Al-4V alloy with each strain waveform can be evaluated by considering the effect of mean-stress, oxidation of specimen surface and creep damage.
    View full abstract
    Download PDF (2485K)
  • High Temperature Strength of Structure-Controlled Ni-Al-Mo In-Situ Composites
    Hitoshi TAKAGI, Koji TAKAHASHI, Sumio FUJIMURA
    2003 Volume 52 Issue 7 Pages 838-842
    Published: July 15, 2003
    Released on J-STAGE: June 03, 2009
    DOIhttps://doi.org/10.2472/jsms.52.838
    JOURNAL FREE ACCESS
    Show abstractHide abstract
    The microstructural-controlling of uni-directionally solidified Ni-Al-Mo in-situ composites has been conducted by changing growth rates and by the addition of rhenium (Re) or iridium (Ir). Oxidation resistance at 1000°C in air and high temperature strength at 800°C of these in-situ composites have also been examined and have been compared with those of conventional Ni-base superalloys, such as MAR-M247 and IN-100. The morphology of strengthening phase, that is Mo phase, changed from fiber-like shape to plate-like shape with increasing the growth rate. A superior oxidation resistance evaluated for 30h was observed for Ni-Al-Mo-Ir in-situ composites. On the other hand, high strength and large fracture strain were obtained for Ni-Al-Mo-Re in-situ composites. Experimental results showed that these composites possessed excellent high temperature properties, which was better than or comparable with those of Ni-base superalloys.
    View full abstract
    Download PDF (3448K)
  • Grain Boundary Strengthening Mechanism of Tungsten Containing 9 to 12% Chromium Ferritic Heat Resistant Steels at 650°C
    Yasushi HASEGAWA, Masahiro OHGAMI, Taro MURAKI
    2003 Volume 52 Issue 7 Pages 843-850
    Published: July 15, 2003
    Released on J-STAGE: June 03, 2009
    DOIhttps://doi.org/10.2472/jsms.52.843
    JOURNAL FREE ACCESS
    Show abstractHide abstract
    Creep strengthening mechanism of tungsten containing 9 to 12% chromium steels for high temperature application was experimentally extracted and discussed from the view point of grain boundary shielding by Fe2W type Laves phase and M23C6 type carbide during the creep exposure at 650°C. Increase of tungsten content from 1.8mass% for ASME Gr. 92 to 2.5mass% for model alloys resulted in the abrupt creep rupture strength deterioration for about 1000 hours creep time. Increase of chromium from 9mass% to 11mass% or more also affected the creep rupture curve. Excess tungsten and chromium almost precipitated grain boundary, and a grain boundary shielding ratio by the precipitates explained the creep rupture behavior, bending of the curves, in tungsten or chromium increased model alloys according to the analyze by thin foil observation through the Transmission Electron Microscope (TEM) with Energy Dispersive X-ray Spectroscopy. Grain boundary shielding possibly delayed the recovery of dislocation substructure by rigid grain structure. Grain boundary shieldng ratio f0/f expressed the creep curves of model alloys based on the dislocation density degradation at 650°C. Species of precipitates did not seem to affect the dynamic recrystalization of a grain boundary.
    View full abstract
    Download PDF (3051K)
  • High-Pressure Phase Diagram of Mg-Al Alloys and Variation of Mechanical Properties in Solid Solutioning and Aging Process
    Akihito MATSUMURO, Futoshi MAEKAWA, Masaya MITSUDA, Iwao KONDO, Yutaka ...
    2003 Volume 52 Issue 7 Pages 851-856
    Published: July 15, 2003
    Released on J-STAGE: June 03, 2009
    DOIhttps://doi.org/10.2472/jsms.52.851
    JOURNAL FREE ACCESS
    Show abstractHide abstract
    The high-pressure phase diagram of a magnesium-rich Mg-Al alloy at a 5.4GPa pressure was investigated. To determine the equilibrium state under high-pressure and high-temperature conditions, the quenching method was applied and a phase analysis of the sample was performed using X-ray diffraction and microscopic observations. The resultant solid solubility of aluminum in magnesium was subsequently increased up to 20at% and the eutectic temperature up to 500°C. The variations of elastic moduli and micro-Vickers hardness for supersaturated Mg-Al solid-solutions against the aluminum concentration and during isochronal ageing were measured. Especially, the attractive increase in hardness for Mg-20at%Al solid solution was observed. Hardness per unit density after ageing at 120°C for 3h increased more than those of extra super duralumin A7075 and Ti-6Al-4V.
    View full abstract
    Download PDF (2333K)
  • Development of High-Strength Cross-Ply “Green” Composites
    Shinji OCHI, Hitoshi TAKAGI, Hideyuki TANAKA
    2003 Volume 52 Issue 7 Pages 857-862
    Published: July 15, 2003
    Released on J-STAGE: June 03, 2009
    DOIhttps://doi.org/10.2472/jsms.52.857
    JOURNAL FREE ACCESS
    Show abstractHide abstract
    This paper discusses the development of high-strength biodegradable, “green”, cross-ply fabric-reinforced composites. The composites were made using woven Manila hemp fibers as the reinforcement and starch-based emulsion-type biodegradable polymer as the matrix. The mechanical properties of the composites have been evaluated as a function of fiber content (20 to 75mass%). The experimental results indicate that the composites show the flexural and tensile strength of 104MPa and 153MPa, respectively. Both of tensile and flexural modulus and flexural strength increased with increasing the fiber content. However, the tensile strength increased with the fiber content till 50mass% and remained constant thereafter. This dependence on the fiber content is due to the decrease in fiber strength caused by fiber damages introduced during hot-pressing.
    View full abstract
    Download PDF (4801K)
  • Sintering for Grinding Swarf of Bearing Steel by Pulsed Electric Current Sintering
    Hitoshi TAKAGI, Sumio FUJIMURA, Akihiro ITO, Tetsuya YAMANO, Hisakazu ...
    2003 Volume 52 Issue 7 Pages 863-866
    Published: July 15, 2003
    Released on J-STAGE: June 03, 2009
    DOIhttps://doi.org/10.2472/jsms.52.863
    JOURNAL FREE ACCESS
    Show abstractHide abstract
    This paper deals with sintering behavior of grinding swarf of bearing steel, which abundantly discharged while ball or roller bearings are manufacturing. The grinding swarf is investigated whether it is possible to use as P/M raw materials applied to machinery parts. Two kinds of sintering processes were used as a powder forming method, that is pulsed electric current sintering (PECS) and vacuum sintering (VS). The effects of sintering temperature and pressing pressure in the sintering on their mechanical properties and microstructure were evaluated. The density for PECS materials was higher than that for VS materials. In addition, the bending strength for PECS materials with high density was extremely higher than that for VS materials. It is concluded that the PECS is a suitable sintering method for the grinding swarf to get high density and high strength materials.
    View full abstract
    Download PDF (3178K)
  • Changes of Color and Psychological Images of Wood Used for Exterior
    Yoshihiro SUGIE, Minoru MASUDA
    2003 Volume 52 Issue 7 Pages 867-872
    Published: July 15, 2003
    Released on J-STAGE: June 03, 2009
    DOIhttps://doi.org/10.2472/jsms.52.867
    JOURNAL FREE ACCESS
    Show abstractHide abstract
    Relations between psychological visual images of exterior wooden walls and their visual physical characteristics were investigated. Forty-two photos of different weathered wooden walls ware distributed to 18 male subjects and 19 female subjects and were arranged in orders according to “Furusouna (aged)”, “Yogoreta (dirty)” and “Kanjino yoi (good impression)”. These three words have high correlation between each other. Especially “Yogoreta (dirty)” and “Kanjino yoi (good impression)” have extremely high correlation between them (r=-0.983). Wooden walls with low lightness L* and low chroma C* give us “Furusouna (aged)” image. Average difference of hue between adjacent mosaics i. e. ΔH°12×12 has high correlation between these three phychological images. Prediction formula for “Furusouna (aged)” Ia obtained by multi-regression analysis is
    Ia=2.492×log(ΔH°16×16)-0.027×L*av-0.555
    View full abstract
    Download PDF (2822K)
  • Fundamentals and Recent Topics on Fatigue
    VI: Computer Aided Fatigue Design System
    Akio INOUE, Sumio YOSHIOKA, Toshio YOSHIDA, Toshio SHUTO
    2003 Volume 52 Issue 7 Pages 873-878
    Published: July 15, 2003
    Released on J-STAGE: June 03, 2009
    DOIhttps://doi.org/10.2472/jsms.52.873
    JOURNAL FREE ACCESS
    Download PDF (5018K)
  • [title in Japanese]
    [in Japanese], [in Japanese], [in Japanese], [in Japanese]
    2003 Volume 52 Issue 7 Pages 882
    Published: July 15, 2003
    Released on J-STAGE: June 03, 2009
    DOIhttps://doi.org/10.2472/jsms.52.882
    JOURNAL FREE ACCESS
    Download PDF (883K)
    • |<
    • <
    • 1
    • >
    • >|
feedback
 Top