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Volume 74, Issue 4
Displaying 1-11 of 11 articles from this issue
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Regular Articles
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Xinbao Liu, Kota Sawada, Hisashi Yamawaki, Makoto Watanabe, Fuxing Yin ...2010 Volume 74 Issue 4 Pages 227-230
Published: 2010
Released on J-STAGE: April 01, 2010
JOURNAL FREE ACCESSCharacterization of the internal friction properties of 2.25Cr-1Mo steel was performed with the forced flexural oscillation by a dynamic mechanical analyzer (DMA). Over the range of variables (temperature, frequency, and vibration strain amplitude) normally encountered in service applications, the results show that the internal friction and modulus of 2.25Cr-1Mo steel at elevated temperatures were dependent not only on the temperature, but also on the frequency. Meanwhile, the internal friction was independent of strain amplitude in the present range below 2×10−4. According to analysis of the above results, it indicated that the internal friction consists of two components. Both components are due to relaxation mechanisms: the first is a thermoelastic relaxation and the second is a broad diffusion-controlled relaxation.
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Takayoshi Matsunaga, Kota Kadoi, Hideo Nakae2010 Volume 74 Issue 4 Pages 231-236
Published: 2010
Released on J-STAGE: April 01, 2010
JOURNAL FREE ACCESSThe influence of the growth direction on the structure of the Al-Ni eutectic alloy was studied. In order to investigate the solidification phenomena in a gravitational environment, downward unidirectional solidification (in the direction of gravity) and upward unidirectional solidification (in the opposite direction of gravity) were carried out. A zone-melting technique was used for the evaluation of the unidirectional solidification under constant experimental conditions. The upward unidirectional solidification leads to the solid/liquid interface with the morphology of the typical faceted/non-faceted eutectic. On the other hand, in the case of the downward unidirectional solidification, the leading phase of the eutectic solidification transforms from Al3Ni into α-Al with the increasing solidification rate. This must be caused by the concentration distribution of nickel due to the density difference between aluminum and nickel. At the front of the solid/liquid interface upward solidified, the nickel concentration decreases with the increasing distance from the interface even though the liquid phase during the downward solidification has a constant concentration value. Therefore, the result indicates that the interface morphology must be influenced by the amount of nickel supplied to the Al3Ni phase. The supply depends on the nickel concentration corresponding to the solidification direction.
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Chikage Abe, Fuyuki Sakamoto, Naofumi Ohtsu, Tetsuya Ashino, Kazuaki W ...2010 Volume 74 Issue 4 Pages 237-241
Published: 2010
Released on J-STAGE: April 01, 2010
JOURNAL FREE ACCESSA quantitative analysis of calcium phosphate (CP) layers deposited on metallic titanium substrates was carried out by X-ray fluorescence spectrometry (XRF) in order to evaluate the osteogenic capability of metallic biomaterials. The titanium substrates were prepared by NaOH and heat treatments, and then, they were soaked in Hanks' balanced saline solution (HBSS) at 310 K, leading to the deposition of a CP layer on the sample surface. The resulting samples were analyzed by XRF, and the amount of Ca and P in the CP layers was determined by inductively coupled plasma optical emission spectrometry (ICP-OES). As a result, calibration curves were obtained for determining the amounts of Ca, P and the CP deposition; the XRF quantification of the CP layers was carried out with good accuracy.
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Nahoko Sugioka, Masahiro Kitada2010 Volume 74 Issue 4 Pages 242-249
Published: 2010
Released on J-STAGE: April 01, 2010
JOURNAL FREE ACCESSThe distribution and nanostructure of the orange dyestuff compound, Pb2CrO5, in cotton fiber used for touzan fabric made in the late Edo period have been investigated. Dyed fiber specimens are taken from old touzan fabric. To observe the distribution of nanometer-sized compound grains in the fiber, the cross section of the fiber is flattened by ion milling after mechanical polishing. The macrostructure is observed by X-ray CT. The nanostructure is observed by SEM and TEM. The composition and crystal structure are analyzed by EDS, XRD and ED. The dye compound, Pb2CrO5, is mainly detected by EDS and XRD. Fine acicular precipitates of Pb2CrO5 are aligned along the fiber, forming concentric circles. The Pb2CrO5 needlelike crystals have lengths and widths of 100~300 nm and 20~50 nm, respectively. However, the needlelike precipitate consists of an aggregation of many nanometer-size Pb2CrO5 crystals. Preferential precipitation is observed at cracks in the fiber, and precipitation-free zones near the fiber surface, in the area of the fiber lumen and in the area near the crack are also observed. It is thought that the Pb2CrO5 nano-crystals nucleate and grow in the amorphous area in the fiber. A possible nucleation and growth model of the Pb2CrO5 crystal is proposed.
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Manako Tanaka, Masahiro Kitada2010 Volume 74 Issue 4 Pages 250-257
Published: 2010
Released on J-STAGE: April 01, 2010
JOURNAL FREE ACCESSThe composition and microstructure of nonmetallic inclusions of a Japanese matchlock gun, called Hinawa-ju in Japanese, fabricated in the Edo period have been investigated. The purpose of this work is to study the composition and microstructure of nonmetallic inclusions of the barrel and to obtain modern materials-science data of the raw materials of the Japanese matchlock gun. Test pieces are cut from the center and the male screw of the barrel. Nonmetallic inclusions of the barrel are observed using an optical microscope and scanning electron microscope (SEM). The small-area concentration of a nonmetallic inclusion is obtained by electron dispersive X-ray analysis (EDS). The electron backscattering pattern (EBSP) is analyzed using an ultrahigh-resolution scanning electron microscope. Fe, Si, Al, Ca, K, Mg, P, Na and Ti are detected from nonmetallic inclusions of the center of the barrel. As Ti is detected from many parts of the nonmetallic inclusions, iron sand is inferred to have been used as the raw iron material of the barrel. Nonmetallic inclusions of the center of the barrel are classified into two groups. One is a plural phase and is consisted of FeO (wustite), Fe-Si-O grains, multi-element grains and glass-rich matrix oxide. The other type is a single phase of aluminum silicate glass. Fe, Si, Al, Ti, Ca, Mg, K, Na, P, Mn and S are detected from nonmetallic inclusions of the male screw of the barrel. As Ti is detected from many parts of the nonmetallic inclusions, iron sand is again thought to have been used as the raw iron material of the male screw. Nonmetallic inclusions of the male screw are of the plural phase and consist of Fe-Ti-O grains, aluminum silicate oxide and aluminum silicate glass matrix.
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Yohei Sakakibara, Keiji Kubushiro, Guen Nakayama2010 Volume 74 Issue 4 Pages 258-263
Published: 2010
Released on J-STAGE: April 01, 2010
JOURNAL FREE ACCESSEBSD is a powerful tool to analyze strains in metallic materials, and various ways are established, such as KAM (Kernel Average Misorientation), GOS (Grain Orientation Spread), GROD (Grain Reference Orientation Spread), to estimate the strains. However, they are not focused on the grain boundary that plays an important role in polycrystalline when the materials are deformed. In this study, we focus on the distribution of misorientation near the grain boundary (DMGB) to estimate the influence of deformation to the grain boundary. The type 316NG deformed by various kinds of loading modes are prepared and the DMGBs in them are higher than one in the material as received. Besides, the DMGB in material deformed by constant strain mode which is simulated a welding process are the highest. It means DMGB has the possibility to estimate the effect of temperatures on deformations.
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Shun Saso, Yoshihito Matsumura, Yoshitake Nishi2010 Volume 74 Issue 4 Pages 264-268
Published: 2010
Released on J-STAGE: April 01, 2010
JOURNAL FREE ACCESSEffects of thickness ratio of Fe-Sm and Fe-Tb films on magnetostriction, bending strain and its force driven by magnetic field were investigated for the mover device of three layered Fe-Sm/Si/Fe-Tb composite prepared by direct current magnetron sputtering process under the residual gas pressure of less than 4.0×10−4 Pa before argon sputtering and the sputtering pressure of argon gas (5N) of 2.0×10−1 Pa. Magnetostriction, bending strain and its force of the mover composites were strongly contributed by film thickness ratio of [Fe-Sm]/[(Fe-Sm)+(Fe-Tb)]. The high susceptibility with low bending strain was obtained for the device with the high film thickness ratio, whereas the high bending strain with low susceptibility was gotten for the device with the low thickness ratio.
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Keisuke Takata, Keisuke Iwata, Akira Tonegawa, Yoshitake Nishi2010 Volume 74 Issue 4 Pages 269-273
Published: 2010
Released on J-STAGE: April 01, 2010
JOURNAL FREE ACCESSEffects of silane coupling treatment and electron beam (EB) irradiation on bending test of glass fiber reinforced epoxy polymer (GFRP) thick sheet were studied. EB irradiation increased the bending strength and its strain of GFRP thick sheet with silane coupling treatment. EB irradiation also enhanced the apparent hardening modulus (dσ/dε) of bending deformation and increased the deformation energy of GFRP thick sheet with silane coupling treatment. The deformation energy depends on the strain improvement at the maximum bending stress of epoxy resin and glass fiber and the interfacial friction force.
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Tatsuya Yamamoto, Yoshihide Ebihara, Yoshitake Nishi2010 Volume 74 Issue 4 Pages 274-278
Published: 2010
Released on J-STAGE: April 01, 2010
JOURNAL FREE ACCESSEffect of water absorption on Charpy impact value has been studied for a carbon fiber reinforced polyimide (CFRP). The water absorption for 200,000 s lasting more than two days enhanced the impact value and softened the CFRP. The impact value was 13.4% higher than that of CFRP before treatment, although it. The water absorption also enhanced Weibull coefficient (n), indicator of reproducibly, and the lowest impact value (as) estimated by modified Weibull equation for safety design. Consequently, the high reliability of CFRP was confirmed even in the water absorbed envelopment.
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Toshio Osada, Yuefeng Gu, Tadaharu Yokokawa, Hiroshi Harada2010 Volume 74 Issue 4 Pages 279-284
Published: 2010
Released on J-STAGE: April 01, 2010
JOURNAL FREE ACCESSThe grain growth behaviors of a new Ni-Co-base superalloy (TMW-4M3) at various temperatures from 1100°C to 1200°C were investigated. The grain grew slowly below solvus temperature, Ts (Ts≈1162°C) and grew very quickly above the temperature because the primary γ' dissolved completely. Therefore, we suggest that Ts≈1162°C is the γ' solvus temperature for TMW-4M3 alloy. Meanwhile, below the γ' solvus temperature, we found that the grain radius, R (µm) was a function of γ' precipitate radius, rγ' (µm) and volume fraction, fV, of the primary γ' phase, which could be expressed as,
R =0.711 · (rγ'/fV )
Thus, the grain growth behavior of the alloy within the γ' sub-solvus temperature range, showed a good agreement with the Zener model.
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Letters to the Editor
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Yoshihiko Hangai, Shinji Koyama, Takao Utsunomiya, Makoto Hasegawa2010 Volume 74 Issue 4 Pages 285-287
Published: 2010
Released on J-STAGE: April 01, 2010
JOURNAL FREE ACCESSPorous aluminum is a multifunctional material with lightweight and high energy absorption properties. In this study, using A1050 and A6061 (Al-Si-Mg aluminum alloy), functionally graded porous aluminum was fabricated by friction stir processing (FSP) route precursor method. First, A1050 and A6061 precursors were fabricated separately by FSP route. Next, these precursors were bonded by friction stir welding (FSW) and “composite graded precursor” was fabricated. Finally, precursor was heat-treated for foaming and A1050-A6061 functionally graded porous aluminum was fabricated. By EPMA observation, existence of Mg atoms was gradually changing at the bonding region. It was shown that seamless functionally graded porous aluminum can be fabricated by FSP route.
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